Mainstay Medical Announces Publication of the First Neuromodulation Study for Low Back Pain with 5-Year Follow-Up

Groundbreaking ReActiv8-B study supports the long-term efficacy, safety and durability of ReActiv8® Restorative NeurostimulationTM for the treatment of intractable Chronic Low Back Pain

Mainstay Medical Holdings plc today announced the publication of the 5-year follow up from the ReActiv8-B randomized, sham-controlled, double-blinded trial. There were 126 patients who completed the 5-year follow up, and the published data clearly indicated that ReActiv8® Restorative Neurostimulation is a long-term, effective, durable, and safe therapy. ReActiv8 is the only restorative therapy for patients suffering from non-surgical, mechanical CLBP evidenced by multifidus dysfunction.

The publication is available here: https://www.sciencedirect.com/science/article/pii/S1094715924000552

The ReActiv8-B study saw multiple patients have their implants removed for resolution of back pain. These removals for success suggest a restorative mechanism, and the therapy shows no evidence of the loss of efficacy commonly observed with palliative treatments.

Dr. Chris Gilligan, Chief Medical Officer and Chief Quality Officer at Robert Wood Johnson University Hospital, stated: “The long-term, durable patient outcomes from this study are unprecedented in the field of neuromodulation. This is truly a unique therapy that is restorative in nature and does not show any of the loss of efficacy seen with other treatments in our field. With 5 year published outcomes, we are no longer limited to providing temporary or palliative treatments to our patients. ReActiv8 is changing the way we treat properly selected patients.”

Jason Hannon, CEO of Mainstay Medical, stated: "We are proud to have the only commercially available device with a strong safety profile and long-term, peer-reviewed evidence supporting the rehabilitation of this severely affected patient population. We look forward to sharing this data with our physician customers and their patients, as well as using it to further engage managed care organizations in the United States to expand commercial insurance access to this incredible therapy.”

About ReActiv8®

ReActiv8 is an implantable medical device designed to treat adults with intractable chronic low back pain (CLBP) associated with multifidus muscle dysfunction. Multifidus muscle dysfunction may be evidenced by imaging or physiological testing in adults who have failed therapy including pain medications and physical therapy, and who are not candidates for spine surgery. ReActiv8 has received regulatory approval in several geographic areas, and is commercially available in the European Economic Area, Australia, the UK, and the US.

About Mainstay Medical

Mainstay Medical is a medical device company focused on commercializing its innovative implantable Restorative Neurostimulation system, ReActiv8, for people with disabling mechanical CLBP. Mainstay Medical is headquartered in Dublin, Ireland and has subsidiaries operating in Ireland, the United States, Australia, Germany, and the Netherlands.

Further information can be found at www.mainstaymedical.com.

Mainstay Medical Announces Publication of Clinical Results Comparing Older Patients and Younger Patients

Efficacy of ReActiv8® Restorative Neurostimulation™ shows no statistically or clinically meaningful differences between older and younger patient populations.

Mainstay Medical Holdings plc today announced the publication of a pooled analysis of three different clinical studies that evaluated the safety and efficacy of ReActiv8 therapy after two years in patients of various ages. The analysis, published in Regional Anesthesia & Pain Medicine, included 261 patients across the ReActiv8-B, ReActiv8-C, and PMCF studies, with the results demonstrating that age is not a factor when utilizing ReActiv8 to treat intractable mechanical chronic low back pain patients with multifidus dysfunction.

The publication can be found here: https://rapm.bmj.com/content/early/2024/03/08/rapm-2023-105032

There were no statistically significant or clinically meaningful differences between the groups in the magnitude or durability of response across pain, disability, or health-related quality of life measures. A summary of some of the data from the analysis for patients at two years of ReActiv8 therapy is as follows:

Dr Simon Thomson MBBS FFPMRCA, Consultant Lead at the Pain and Neuromodulation Centre, Mid and South Essex University Hospitals NHS, Essex, UK and the London Clinic, former President of International Neuromodulation Society (INS), stated: “Restorative Neurostimulation has proven to be a unique therapy that delivers consistent results in randomized, controlled and real-world studies. Until now it was unknown if age was a factor in predicting long-term outcomes. This pooled analysis demonstrates that properly selected patients can benefit from this therapy, irrespective of age.”

Jason Hannon, CEO of Mainstay Medical, stated: “High quality clinical evidence sets us apart in this industry. We study, learn, and demonstrate outcomes in patient populations before we suggest ReActiv8 is beneficial to a particular group of patients. This is how we partner with clinicians to deliver the best possible, and most durable, treatments for their patients. With these exciting results demonstrating the value of ReActiv8 across all studied age groups, we can now confidently support identification of older patients who are likely to benefit from the therapy. We look forward to continuing to partner with physicians to help chronic low back pain patients of all ages, and to growing the global body of peer-reviewed evidence supporting the ability of ReActiv8 to provide positive long-term outcomes.”

About ReActiv8®

ReActiv8 is an implantable medical device designed to treat adults with intractable chronic low back pain (CLBP) associated with multifidus muscle dysfunction. Multifidus muscle dysfunction may be evidenced by imaging or physiological testing in adults who have failed therapy including pain medications and physical therapy, and who are not candidates for spine surgery. ReActiv8 has received regulatory approval in several geographic areas, and is commercially available in the European Economic Area, Australia, the UK, and the US.

About Mainstay Medical

Mainstay Medical is a medical device company focused on commercializing its innovative implantable Restorative Neurostimulation system, ReActiv8, for people with disabling mechanical CLBP. Mainstay Medical is headquartered in Dublin, Ireland and has subsidiaries operating in Ireland, the United States, Australia, Germany, and the Netherlands.

Further information can be found at www.mainstaymedical.com.

Mainstay Medical Announces US$125 Million Equity Financing Transaction

Funding to accelerate commercial growth and expand clinical and health economic evidence for ReActiv8® Restorative NeuromodulationTM System

Mainstay Medical Holdings plc today announced an equity financing in which it will receive gross proceeds of US$125 million. Mainstay intends to use the funds to support the company’s continued commercial growth of ReActiv8® Restorative Neurostimulation in the U.S., Europe and Australia, additional post-market clinical studies and research, and general operations.

The financing was co-led by new investors Gilde Healthcare and Viking Global Investors. Key existing investors who participated in the financing include Ally Bridge Group, Sofinnova Partners (Crossover Fund), Fountain Healthcare Partners, and Perceptive Advisors.

“A financing of this magnitude will allow us to accelerate our efforts to revolutionize the treatment of mechanical low back pain through ReActiv8 Restorative Neurostimulation, including by continuing our rapid commercial growth and building on our insurance coverage for ReActiv8,” said Jason Hannon, CEO of Mainstay Medical. “We are now strongly capitalized to execute on our corporate objectives. In addition to commercial expansion in our target markets, these objectives include the generation of additional clinical and health economic data to further demonstrate that ReActiv8’s purpose-built, restorative approach to the treatment of mechanical chronic low back pain is superior to competitive therapies originally designed for other indications, as well as the continued development and enforcement of our dominant intellectual property portfolio.”

“We are excited to lead this financing and to work with Mainstay to continue to unlock the potential of ReActiv8 therapy,” said Geoff Pardo, Partner at Gilde Healthcare, who also joins the Mainstay Medical Board of Directors. “Patients with mechanical chronic low back pain have had very limited treatment options, and the restorative mechanism of action offered by ReActiv8 is both unique and very promising.”

Two extraordinary general meetings of Mainstay shareholders were held on 23 February 2024 to approve the financing and related matters. At the EGMs, all resolutions were duly passed. The results of the voting on each of the resolutions is available on the Company’s website.

About ReActiv8®

ReActiv8 is an implantable medical device designed to treat adults with intractable chronic low back pain (CLBP) associated with multifidus muscle dysfunction. Multifidus muscle dysfunction may be evidenced by imaging or physiological testing in adults who have failed therapy including pain medications and physical therapy, and who are not candidates for spine surgery. ReActiv8 has received regulatory approval in several geographic areas, and is commercially available in the European Economic Area, Australia, the UK, and the US.

About Mainstay Medical

Mainstay Medical is a medical device company focused on commercializing its innovative implantable Restorative Neurostimulation system, ReActiv8, for people with disabling mechanical CLBP. Mainstay Medical is headquartered in Dublin, Ireland and has subsidiaries operating in Ireland, the United States, Australia, Germany, and the Netherlands.

Further information can be found at www.mainstaymedical.com.

Mainstay Medical Announces Receipt of FDA Approval for MRI Labeling on ReActiv8® Restorative Neurostimulation SystemTM

U.S. patients implanted with ReActiv8 now eligible for full-body MRI scans

Mainstay Medical Holdings plc today announced that the U.S. Food and Drug Administration (FDA) has approved full-body MRI conditional labeling for the ReActiv8® Restorative Neurostimulation system. This approval applies to all current and future ReActiv8 patients in the United States implanted with the current 45 cm commercially-available leads.

The approval provides patients implanted with ReActiv8 the ability to undergo 1.5T full-body MRI scans. Specific scan conditions and safety information are provided in the ReActiv8 FDA MRI Guidelines manual.

“This approval expands the existing safety profile of ReActiv8, broadening access to patients who may need (or develop the need) for MRI imaging after implant,” stated Jason Hannon, Chief Executive Officer of Mainstay Medical. “The ReActiv8 MRI labeling is one of the most comprehensive among neurostimulation devices approved for chronic low back pain, with full-body imaging at 1.5T at normal operating mode (maximum specific absorption rate (SAR) of 3.2 W/kg for the head and 2.0 W/kg for the rest of the body). We look forward to building on this as we seek conditional MRI compatibility in Europe and Australia.”

About ReActiv8®

ReActiv8 is an implantable medical device designed to treat adults with intractable chronic low back pain (CLBP) associated with multifidus muscle dysfunction. Multifidus muscle dysfunction may be evidenced by imaging or physiological testing in adults who have failed therapy including pain medications and physical therapy, and who are not candidates for spine surgery. ReActiv8 has received regulatory approval in several geographic areas, and is commercially available in the European Economic Area, Australia, the UK, and the US.

About Mainstay Medical

Mainstay Medical is a medical device company focused on commercializing its innovative implantable Restorative Neurostimulation system, ReActiv8, for people with disabling mechanical CLBP. Mainstay Medical is headquartered in Dublin, Ireland and has subsidiaries operating in Ireland, the United States, Australia, Germany, and the Netherlands.

Further information can be found at www.mainstaymedical.com.

Mainstay Medical Announces Completion of Enrollment of RESTORE Clinical Trial of ReActiv8® in the United States

Randomized controlled clinical trial expected to validate effectiveness of ReActiv8® Restorative NeurostimulationTM vs. optimal medical management

Mainstay Medical Holdings plc today announced the completion of enrollment in its RESTORE randomized clinical study of ReActiv8 for the treatment of intractable chronic low back pain. The study is designed to provide a direct comparison to optimized medical management for the purpose of testing the hypothesis that the addition of ReActiv8 Restorative Neurostimulation therapy to current care paradigms results in significant improvements in back pain-related disability.

The RESTORE (ReActiv8 Stimulation Therapy vs Optimal Medical Management: A Randomized Evaluation) clinical study is a prospective, randomized controlled trial conducted at 25 leading centers in the U.S. Eligible patients were randomized to either continue with their optimal medical management or ReActiv8 Restorative Neurostimulation therapy plus optimal medical management. Patient-reported outcomes are being collected at regular intervals out to the one-year primary endpoint, at which time the patients in the control arm are offered implantation with the ReActiv8 system. The Co-Principal Investigators of the RESTORE study are Dr. Frank Schwab, Chair of Orthopedic Spine Surgery at Lenox Hill Hospital and Chief of Orthopedic Spine Surgery for Northwell Health System; Dr. Chris Gilligan, Director of the Spine Center at Brigham and Women’s Hospital and assistant professor of Anesthesia at Harvard Medical School; and Dr. Kiran Patel, Director of Pain Medicine, Lenox Hill Hospital and Founder & CEO, NYC Neuromodulation Center of Excellence.

Jason Hannon, CEO of Mainstay Medical, stated: “We are proud to have reached this important milestone in the RESTORE clinical trial as we continue to demonstrate the clinical efficacy and positive economic impact of ReActiv8. We expect the initial data readout from the study in the second half of 2024, and we look forward to sharing the data with our physician customers and their patients, as well as using it to further engage managed care organizations in the United States to expand commercial insurance access to this incredible therapy. I would like to thank Dr. Frank Schwab, Dr. Chris Gilligan, and Dr. Kiran Patel for acting as Co-Principal Investigators of this important study, as well as each of the enrolling sites and all of the participating patients.”

“This type of randomized, controlled clinical trial in this difficult-to-treat and underserved patient population will produce high-quality data comparing ReActiv8 to the current standard of care,” said Drs. Frank Schwab, Chris Gilligan, and Kiran Patel, Co-Principal Investigators of the RESTORE study. “Once the data is published, it will meaningfully add to the growing body of clinical evidence regarding ReActiv8 and firmly establish the role of this therapy in treating mechanical low back pain patients.”

Drs. Schwab, Gilligan, and Patel continued: ”The RESTORE trial represents a substantial addition to the clinical evidence behind treatment options for this patient population who have extremely limited options beyond temporary palliative treatments and drugs. Directly addressing the underlying issue of muscular dysfunction can represent a substantial advancement in treatment options. We would like to express sincere thanks to the patients who agreed to be screened for this study, the trial investigators and their hard-working staff, and the Mainstay team for their passion and commitment to the program. We look forward to the results of this trial to prove the degree to which ReActiv8 can improve the lives of these patients above and beyond what is currently used to treat them.”

About the RESTORE Clinical Study

The RESTORE clinical study is a multi-center, prospective, randomized trial with one-way cross-over. A total of 226 patients were randomized in the study at 25 leading centers in the U.S. Eligible patients were randomized to either continue with their optimal medical management or ReActiv8 Restorative Neurostimulation therapy plus optimal medical management. Patient-reported outcomes are being collected at regular intervals out to the one-year primary endpoint, at which time the patients in the control arm are offered implantation with the ReActiv8 system. Assessment of the patients will continue for an additional year.

About ReActiv8®

ReActiv8 is an implantable medical device designed to treat adults with intractable chronic low back pain (CLBP) associated with multifidus muscle dysfunction, which may be evidenced by imaging or physiological testing. Candidates for ReActiv8 are patients with multifidus muscle dysfunction who have failed other forms of therapy (including pain medication and physical therapy) and are not candidates for spine surgery. ReActiv8 has received regulatory approval in several geographic areas, and is commercially available in the European Economic Area, Australia, the UK, and the US.

About Mainstay Medical

Mainstay Medical is a medical device company focused on commercializing its innovative implantable Restorative Neurostimulation system, ReActiv8®, for people with disabling mechanical CLBP. Mainstay Medical is headquartered in Dublin, Ireland and has subsidiaries operating in Ireland, the United States, Australia, Germany, and the Netherlands.

Further information can be found at www.mainstaymedical.com.

Mainstay Medical Announces Publication of Three-Year Clinical Trial Data from Post-Market Clinical Follow-up Registry of ReActiv8® in the United Kingdom

Further real-world evidence supporting the efficacy and use of ReActiv8® Restorative NeurostimulationTM for the treatment of intractable Chronic Low Back Pain

Mainstay Medical Holdings plc today announced the publication of three-year clinical data from the Post-Market Clinical Follow-up (PMCF) study of 33 ReActiv8 patients from five medical centres across the United Kingdom. The three-year results, published in British Journal of Pain, demonstrated that a substantial portion of patients experienced statistically significant improvements in measures of pain (NRS), disability (ODI) and quality of life (EQ-5D-5L). The publication can be found here: https://journals.sagepub.com/doi/10.1177/20494637231181498.

These results indicate that the response to ReActiv8 for these patients is durable and improves over time, validating ReActiv8’s restorative mechanism of action. In addition, these real-world outcomes are consistent with the three-year data from the pivotal ReActiv8-B clinical trial, announced in September 2022, as shown in the following table:

Dr. Simon Thomson MBBS FFPMRCA, Consultant Lead at the Pain and Neuromodulation Centre, Mid and South Essex University Hospitals NHS, Essex, UK, stated: “These results demonstrate durability and safety of this therapy in chronic back pain sufferers who would have continued to be crippled and dominated by their symptoms but for ReActiv8. These patients, drawn from usual UK Pain clinics, are now as good as those seen in the continuation cohort from the more highly selected randomised ReActiv8-B trial.”

Jason Hannon, CEO of Mainstay Medical, stated: “We are pleased to add these compelling results to the growing global body of positive peer-reviewed evidence supporting the ability of ReActiv8 to provide positive long-term outcomes to this severely affected patient population. Most importantly, the continued improvement in patient outcomes observed in the real-world setting is consistent with the results from our controlled clinical trials.”

About ReActiv8®

ReActiv8 is an implantable medical device designed to treat adults with intractable chronic low back pain (CLBP) associated with multifidus muscle dysfunction, which may be evidenced by imaging or physiological testing. Candidates for ReActiv8 are patients with multifidus muscle dysfunction who have failed other forms of therapy (including pain medication and physical therapy) and are not candidates for spine surgery. ReActiv8 has received regulatory approval in several geographic areas, and is commercially available in the European Economic Area, Australia, the UK, and the US.

About Mainstay Medical

Mainstay Medical is a medical device company focused on commercializing its innovative implantable Restorative Neurostimulation system, ReActiv8®, for people with disabling mechanical CLBP. Mainstay Medical is headquartered in Dublin, Ireland and has subsidiaries operating in Ireland, the United States, Australia, Germany, and the Netherlands.

Mainstay Medical Announces Publication of Three-Year Patient Outcomes Data from ReActiv8-B Clinical Trial Demonstrating Long-Term Efficacy of ReActiv8® Restorative Neurostimulation™

Data continue to show compelling efficacy and safety, including improvement on all key measures of pain and disability, as compared to the one-year and two-year study results

Mainstay Medical Holdings plc today announced the publication of the three-year patient outcomes data from its pivotal ReActiv8-B clinical trial. The data, published in the journal of the International Neuromodulation Society, Neuromodulation, further establish the efficacy and safety of ReActiv8 Restorative Neurostimulation, including compelling long-term durability and improvement over time on key outcome measures in the treatment of intractable chronic low back pain.

The three-year data show improvements over results from the patients’ one-year and two-year visits on virtually all key efficacy measures. Of note:

*Percent of patients that were on opioids at baseline: (1-year=31/65), (2-Year= 34/57), (3-Year= 36/51).

Overall, 83% of patients experienced substantial and clinically meaningful improvements in pain or disability, or both, at three years.

Chris Gilligan, Director of the Brigham and Women’s Spine Center at Brigham and Women’s Hospital, assistant professor of Anesthesia at Harvard Medical School (Boston, USA), and Principal Investigator of the study, said: “The recently published data from the ReActiv8-B clinical trial continued to show clinically meaningful improvements in both pain and function for patients with refractory chronic low back pain who received three years of neurostimulation. The long-term trajectory and durability of clinical benefits are consistent with the restoration of neuromuscular control and muscle rehabilitation, which gives us confidence that we are able to treat the underlying cause of chronic low back pain in these patients.”

“Multifidus dysfunction in patients with chronic low back pain has historically been a challenging etiology for the spine surgeon community to properly treat,” said Frank Schwab, Chair of Orthopedic Spine Surgery at Lenox Hill Hospital, and Chief of Orthopedic Spine Surgery for Northwell Health System. “These patients are not indicated for surgery, with existing treatment options being temporary and palliative. ReActiv8 therapy has proven to maintain effectiveness long-term and provides this challenging patient population with a safe and restorative solution.”

Jason Hannon, CEO of Mainstay Medical, said: "These 3-year results further validate ReActiv8’s restorative mechanism of action, which treats a primary underlying cause of mechanical chronic lower back pain, multifidus dysfunction. We are proud to have the only commercially available device with a strong safety profile and long-term, peer-reviewed evidence supporting the rehabilitation of this severely affected patient population, and we look forward to continuing to generate clinical and other research to compel physicians and their patients to further utilize the therapy.”

The full publication can be downloaded free of charge at Three-Year Durability of Restorative Neurostimulation Effectiveness in Patients With Chronic Low Back Pain and Multifidus Muscle Dysfunction - ScienceDirect

About ReActiv8®

ReActiv8 is an implantable medical device designed to treat adults with intractable chronic low back pain (CLBP) associated with multifidus muscle dysfunction. Multifidus muscle dysfunction may be evidenced by imaging or physiological testing in adults who have failed therapy including pain medications and physical therapy, and who are not candidates for spine surgery. ReActiv8 has received regulatory approval in several geographic areas, and is commercially available in the European Economic Area, Australia, the UK, and the US.

About Mainstay Medical

Mainstay Medical is a medical device company focused on commercializing its innovative implantable Restorative Neurostimulation™ system, ReActiv8®, for people with disabling mechanical CLBP. Mainstay Medical is headquartered in Dublin, Ireland, and has subsidiaries operating in Ireland, the United States, Australia, Germany and the Netherlands.

Further information can be found at www.mainstaymedical.com.

United Kingdom National Institute for Health and Care Excellence (NICE) Publishes Interventional Procedure Guidance (IPG) for ReActiv8® Restorative Neurostimulation™

ReActiv8 Neurostimulation therapy recommended to be used in the National Health Service; Special arrangements designation to increase access to ReActiv8 for patients

Mainstay Medical Holdings plc announced today that the National Institute for Health and Care Excellence (NICE), a public body of the Department of Health that carries out evidence-based health technology assessments by independent committees, has issued a recommendation that ReActiv8® Restorative Neurostimulation™ can be used in the National Health Service in the U.K., with special arrangements for clinical governance, consent, and audit or research. ReActiv8 is currently the only technology offering restorative neurostimulation to the NHS for refractory mechanical chronic low back pain (CLBP).

“U.K. physicians have some of the most extensive experience with ReActiv8 globally. We are thankful to NICE for recognizing this experience, as well as the substantial body of global evidence we have developed in support of the efficacy and safety of this ground-breaking therapy, “ said Jason Hannon, CEO of Mainstay Medical. “This new guidance will enable patients to have greater access to the therapy when previous treatment options have not proven successful. We look forward to supporting physicians across the U.K. going forward and to continued improvement in patient outcomes.”

“Historically, mechanical CLBP pain therapies were aimed at only managing the symptoms, which is the pain associated with this pathology,” said Dr. Ganesan Baranidharan, Consultant in Anaesthesia and Pain Medicine, Leeds Teaching Hospitals NHS Trust. “ReActiv8 is the only therapy available I am aware of where patients with many years of CLBP actually reverse and effectively rehabilitate their condition durably over a long period of time. ReActiv8 targets the cause of mechanical CLBP, not just the symptoms. The new NICE guidance is a major victory for patients and clinicians, which further confirms the positive patient outcomes we have seen to date. This new guidance will allow more patients to gain access to ReActiv8 within the U.K. and further afield.”

The NICE publication can be found here: Evidence | Neurostimulation of lumbar muscles for refractory non-specific chronic low back pain | Guidance | NICE

About ReActiv8®

ReActiv8 is an implantable medical device designed to treat adults with intractable chronic low back pain (CLBP) associated with multifidus muscle dysfunction. Multifidus muscle dysfunction may be evidenced by imaging or physiological testing in adults who have failed therapy including pain medications and physical therapy, and who are not candidates for spine surgery. ReActiv8 has received regulatory approval in several geographic areas, and is commercially available in the European Economic Area, Australia, the UK, and the US.

About Mainstay Medical

Mainstay Medical is a medical device company focused on commercializing its innovative implantable Restorative Neurostimulation™ system, ReActiv8®, for people with disabling mechanical CLBP. Mainstay Medical is headquartered in Dublin, Ireland and has subsidiaries operating in Ireland, the United States, Australia, Germany and the Netherlands.

Further information can be found at www.mainstaymedical.com.

Mainstay Medical Announces Publication of Two-Year Patient Outcomes Data from ReActiv8-B Clinical Trial Demonstrating Long-Term Efficacy of ReActiv8® Restorative Neurostimulation™

Data shows compelling efficacy and safety, as well as improvement on all key measures of pain and disability as compared to the one-year study results

Mainstay Medical Holdings plc today announced the publication of the two-year patient outcomes data from its pivotal ReActiv8-B clinical trial. The data, published in the journal of the International Neuromodulation Society, Neuromodulation, confirm the efficacy and safety of ReActiv8 Restorative Neurostimulation, and also demonstrate compelling long-term durability and improvement over time on key outcome measures in the treatment of intractable chronic low back pain.

On virtually all key efficacy measures, the 2-year data showed improvements over the data from the patients’ 1-year visits. Of note:

Outcome measure 2-year result (N = 156) 1-year result (N = 176)

Patients reporting pain intensity (VAS score) reduced by 50% or more from baseline 71% 64%
Patients reporting a greater than 20-point reduction in Oswestry Disability Index 61% 57%
Patients reporting VAS score < 2.5 65% 52%
Patients taking opioids at baseline that voluntarily eliminated or reduced opioid use 60% 48%

Dr. Chris Gilligan, Director of the Brigham and Women’s Spine Center at Brigham and Women’s Hospital, and Assistant Professor of Anaesthesia, Harvard Medical School, said, “The recently published data from the ReActiv8-B clinical trial showed clinically meaningful improvements in both pain and function for patients with refractory chronic low back pain who received two years of neurostimulation. Pain scores in patients have decreased substantially from an average of 7.3 to 2.4 and are sustained for the duration of 2 years and longer with ongoing data collection. These long-term data are extremely important and encouraging given the chronic and refractory nature of this condition.”

“These impressive results represent an important milestone for Mainstay, as the profound improvements in patient outcomes we observed from baseline to 1 year to 2 years validate the restorative nature of the therapy and represent a new paradigm among treatments available to patients with intractable chronic low back pain,” said Jason Hannon, CEO of Mainstay Medical. “We are proud to have the only commercially available device with a strong safety profile and long-term, peer-reviewed evidence supporting the rehabilitation of this severely affected patient population, evidence which continues to expand through multiple clinical trials.”

The full publication can be downloaded free of charge at https://www.sciencedirect.com/science/article/pii/S1094715921063868. The ReActiv8-B trial patient cohort continues to be evaluated to generate additional data on longer-term efficacy.

About ReActiv8®

ReActiv8 is an implantable medical device designed to treat adults with intractable chronic low back pain (CLBP) associated with multifidus muscle dysfunction. Multifidus muscle dysfunction may be evidenced by imaging or physiological testing in adults who have failed therapy including pain medications and physical therapy, and who are not candidates for spine surgery. ReActiv8 has received regulatory approval in several geographic areas, and is commercially available in the European Economic Area, Australia, the United Kingdom, and the United States.

About the ReActiv8-B Clinical Trial

The ReActiv8-B clinical trial is an international, multi-center, prospective, randomized, active sham-controlled, blinded trial with one-way cross-over, conducted under an Investigational Device Exemption (IDE) from the FDA. A total of 204 patients with chronic low back pain refractory to physical therapy and medical management were implanted with ReActiv8 at leading clinical sites in the U.S., Europe and Australia and randomized 1:1 to therapy or control. In the treatment group, the ReActiv8 pulse generator was programmed to deliver electrical stimulation expected to elicit episodic contractions of the multifidus muscle. In the control group, the ReActiv8 device was programmed to provide a low level of electrical stimulation. Following assessment of the primary endpoint at 120 days, patients in the control group crossed over to receive levels of electrical stimulation similar to those in the treatment group.

Clinical trial funded by Mainstay Medical. Dr. Chris Gilligan, Principal Investigator of the trial, is a consultant of Mainstay Medical. Information about the study can be found at https://clinicaltrials.gov/ct2/show/study/NCT02577354.

About Mainstay Medical

Mainstay Medical is a medical device company focused on commercializing its innovative implantable Restorative Neurostimulation™ system, ReActiv8®, for people with disabling mechanical CLBP. Mainstay Medical is headquartered in Dublin, Ireland and has subsidiaries operating in Ireland, the United States, Australia, Germany and the Netherlands.

Further information can be found at www.mainstaymedical.com.

Mainstay Medical Announces Appointment of Jeffrey Dunn and Eric Major to its Board of Directors

Mainstay Medical Holdings plc today announced the appointment of two new independent members to the company’s board of directors, Jeffrey Dunn and Eric Major. These appointments bring Mainstay’s total board membership to seven.

“We are pleased to welcome these two transformational business leaders as new independent directors on the Board,” said David Brabazon, Chairman of the Mainstay Board of Directors. “Their deep experience will be invaluable to Mainstay as we grow our business and pursue our mission to serve patients with intractable chronic low back pain.”

“As our business evolves and we continue to focus on commercial growth, broadening the industry expertise on our Board will help the company strategically and operationally,” said Jason Hannon, Mainstay’s Chief Executive Officer and Board member. “Both Jeff and Eric have strong track records of success leading medical device companies focused on back pain from the launch phase through maturity. They bring decades of leadership in key areas, such as commercial and reimbursement strategy, new product development and operations, that will be valuable to us as we continue to grow our ReActiv8 business in the U.S. and abroad.”

Mr. Dunn currently serves as the Executive Chairman of the Board of Directors of SI-BONE, Inc. (Nasdaq: SIBN), a medical device company dedicated to solving musculoskeletal disorders of the sacropelvic anatomy. Mr. Dunn co-founded the company and served as its President, Chief Executive Officer and Chairman of the Board of Directors from 2008 until April 2021. Mr. Dunn led the company through the launch and market growth of the iFuse proprietary minimally invasive surgical implant system as well as the company’s 2018 Nasdaq IPO, taking the company from inception to its current market cap of over $700 million. Prior to joining SI BONE, Mr. Dunn held multiple Chief Executive Officer positions in various other companies since 1994. Mr. Dunn received a B.A. from Colgate University and an M.B.A. from Babson College.

Mr. Major has more than 25 years of experience in the spine device industry as an entrepreneur, executive, chairman, and board member. In 2004 Mr. Major co-founded K2M Group Holding, Inc., a global leader in complex spine and minimally invasive medical device solutions, and led the company to $300 million in annual revenue and a Nasdaq IPO in 2014. K2M was acquired by Stryker Corporation for $1.4 billion in 2018, after which Mr. Major served as president of Stryker’s spine division until June 2021. Prior to starting K2M, in 1998 Eric co-founded American OsteoMedix Corporation, a global minimally invasive spine company that was acquired by Interpore Cross (now part of Zimmer Biomet). Mr. Major holds a B.S. from James Madison University.

About ReActiv8®

ReActiv8 is an implantable medical device designed to treat adults with intractable chronic low back pain (CLBP) associated with multifidus muscle dysfunction. Multifidus muscle dysfunction may be evidenced by imaging or physiological testing in adults who have failed therapy including pain medications and physical therapy, and who are not candidates for spine surgery. ReActiv8 has received regulatory approval in several geographic areas, and is commercially available in the European Economic Area, Australia, the UK, and the US.

About Mainstay Medical

Mainstay Medical is a medical device company focused on commercializing its innovative implantable Restorative Neurostimulation™ system, ReActiv8®, for people with disabling mechanical CLBP. Mainstay Medical is headquartered in Dublin, Ireland and has subsidiaries operating in Ireland, the United States, Australia, Germany and the Netherlands.

Further information can be found at www.mainstaymedical.com.

Mainstay Medical Announces Limited Commercial Launch of ReActiv8® in the U.S.

Official launch includes new website and marketing resources to support physician and patient education

Mainstay Medical Holdings plc (the “Company”) today announced the limited commercial launch in the U.S. of ReActiv8, its implantable Restorative Neurostimulation™ system to treat intractable chronic low back pain. The ReActiv8 system will be available in the U.S. through ReActiv8-certified physicians commencing in the summer of 2021.

“We are delighted to commercially launch ReActiv8 in the U.S. and make this innovative Restorative Neurostimulation therapy available to Americans suffering from intractable chronic low back pain. Supported by more than 10 years of clinical research, ReActiv8 is the only proven neurostimulation system to address mechanical intractable low back pain. Physicians will finally have access to a therapy to treat these patients beyond temporary treatments designed to merely mask the pain for a limited time,” said Jason Hannon, CEO of Mainstay Medical. “We are launching in a limited fashion to ensure we provide proper education to physicians and assist them in selecting the appropriate patients. We look forward to expanding the availability of ReActiv8 across the U.S. over the coming months and building on the momentum we have gained in Europe and Australia to continue to improve the quality of patients’ lives.”

To support the U.S. commercial launch, Mainstay Medical has launched a new corporate website centered around patient and physician education. The new company website can be accessed at: https://www.mainstaymedical.com. In addition to the new website, the Company has introduced updated tools, guidance, and training materials to assist in identifying prospective patients for ReActiv8 therapy, educating physicians on the ReActiv8 system and becoming ReActiv8-certified, and helping patients access ReActiv8 in the U.S. Specific resources include physician training protocols and modules on ReActiv8, educational and marketing collateral, and informative videos that support and further physician education, patient identification, and appropriate product use.

“We are equipping ReActiv8-certified physicians with robust tools and information to enable proper patient identification and education. We expect that these resources will facilitate the identification of strong candidates for ReActiv8 and drive compelling patient outcomes,” added Mr. Hannon.

About Mainstay Medical

Mainstay Medical is a medical device company focused on commercializing an innovative implantable Restorative Neurostimulation™ system, ReActiv8®, for people with disabling mechanical Chronic Low Back Pain (CLBP). The Company is headquartered in Dublin, Ireland and has subsidiaries operating in Ireland, the United States, Australia, Germany and the Netherlands.

About ReActiv8®

ReActiv8 is an active implantable medical device designed to treat adults with intractable chronic low back pain associated with dysfunction of the lumbar multifidus muscle, a key stabilizing muscle of the low back, as evidenced by imaging or physiological testing in adults who have failed therapy (including pain medications and physical therapy) and are not candidates for spine surgery. ReActiv8 provides bilateral electrical stimulation of the L2 medial branch of the dorsal ramus nerve as it crosses the transverse process at L3. Stimulation of this nerve that supplies the multifidus muscle elicits contraction of the muscle which can lead to restoration of control over time, allowing the back to recover from CLBP.

ReActiv8 has a CE Mark allowing for commercialization in the European Economic Area. ReActiv8 has also been admitted to the Australian Register of Therapeutic Goods (ARTG), enabling commercialization throughout Australia, and has been approved for inclusion on the Prostheses List of reimbursed products in Australia, effective as of 1 July 2020. The Prostheses List identifies implantable devices eligible for reimbursement from all private health insurance funds in Australia. In the U.S., ReActiv8 is FDA approved and the Company commercially launched the ReActiv8 system in the summer of 2021.

About Chronic Low Back Pain

One of the root causes of CLBP is impaired control by the nervous system of the muscles that dynamically stabilize the spine. ReActiv8® is designed to electrically stimulate the nerves responsible for contracting these muscles to improve dynamic spine stability, allowing for improvement in CLBP and its disabling effects.

People with CLBP usually have a greatly reduced quality of life and score significantly higher on scales for pain, disability, depression, anxiety and sleep disorders. Their pain and disability can persist despite the best available medical treatments, and only a small percentage of cases result from an identified pathological condition or anatomical defect that may be correctable with spine surgery. Their ability to work or be productive is seriously affected by their CLBP and the resulting days lost from work, disability benefits, and health resource utilization, exert a significant burden on individuals, families, communities, industry and governments.

Further information can be found at www.mainstaymedical.com.

Mainstay Medical Announces Commercial Launch of ReActiv8® in Australia

Mainstay Medical Holdings plc (“Mainstay” or the “Company”) today announced the commercial launch in Australia of ReActiv8®, its implantable neurostimulation system to treat chronic low back pain.

“Launching ReActiv8, our Restorative Neurostimulation therapy, commercially in Australia is a significant milestone for our global commercial expansion. Several top Australian physicians have been part of our clinical studies since inception and are among the most experienced globally in selecting and treating patients with ReActiv8. We are excited to make ReActiv8 commercially available to Australian physicians and their patients suffering from mechanical chronic low back pain,” said Jason Hannon, CEO of Mainstay.

The first commercial ReActiv8 implant in Australia was conducted by Associate Professor Bruce Mitchell, Sports and Interventional Pain Physician and Director of Metro Pain Group in Melbourne, Australia.

“Having been involved in both the ReActiv8-A and -B Clinical Trials, I am excited to be able to expand this restorative therapy to other patients in my practice. The launch in Australia is a great milestone for ReActiv8 and, ultimately, the patients that suffer from chronic mechanical low back pain who now have a new treatment option,” said Associate Professor Bruce Mitchell.

About ReActiv8

ReActiv8 is an active implantable medical device designed to treat adults with intractable chronic low back pain associated with dysfunction of the lumbar multifidus muscle, a key stabilizing muscle of the low back, as evidenced by imaging or physiological testing in adults who have failed therapy, including pain medications and physical therapy, and are not candidates for spine surgery. ReActiv8 provides bilateral electrical stimulation of the L2 medial branch of the dorsal ramus nerve as it crosses the transverse process at L3. Stimulation of this nerve that supplies the multifidus muscle elicits contraction of the muscle which can lead to restoration of control over time, allowing the back to recover from CLBP.

The ReActiv8 Restorative Neurostimulation therapy has a CE Mark allowing for commercialization in the European Economic Area and has been focused on building clinical validation in Germany in select centers ahead of wider commercial availability. ReActiv8 has also been admitted to the Australian Register of Therapeutic Goods (ARTG), enabling commercialization throughout Australia, and has been approved for inclusion on the Protheses List of reimbursed products in Australia, effective as of 1 July 2020. The Prostheses List identifies implantable devices eligible for reimbursement from all private health insurance funds in Australia. In the U.S., ReActiv8 is FDA approved and the Company plans to commercially launch in early 2021.

About Chronic Low Back Pain

One of the root causes of CLBP is impaired control by the nervous system of the muscles that dynamically stabilize the spine. ReActiv8 is designed to electrically stimulate the nerves responsible for contracting these muscles to improve dynamic spine stability, allowing for improvement in CLBP and its disabling effects.

People with CLBP usually have a greatly reduced quality of life and score significantly higher on scales for pain, disability, depression, anxiety, and sleep disorders. Their pain and disability can persist despite the best available medical treatments, and only a small percentage of cases result from an identified pathological condition or anatomical defect that may be correctable with spine surgery. Their ability to work or be productive is seriously affected by the condition and the resulting days lost from work, disability benefits and health resource utilization put a significant burden on individuals, families, communities, industry, and governments.

About Mainstay

Mainstay is a medical device company focused on commercializing an innovative implantable Restorative Neurostimulation system, ReActiv8®, for people with disabling mechanical chronic low back pain (“CLBP”). The Company is headquartered in Dublin, Ireland and has subsidiaries operating in the United States, Australia, Germany, and the Netherlands.

Further information can be found at www.mainstay-medical.com

Mainstay Medical Announces US$108 Million Equity Financing Transaction

Funding to support U.S. commercial launch and global expansion

Mainstay Medical Holdings plc (“Mainstay” or the “Company”) today announced the closing of an equity financing in which it raised gross proceeds of US$108 million. Mainstay intends to use the funds to support the company’s commercial launch of ReActiv8® in the U.S., continued expansion in Europe and Australia, additional post-market clinical studies and research, and general operations.

The financing was co-led by new investors Ally Bridge Group and Sofinnova Partners, through its Crossover Fund, and also included a large, global medical device company. Key existing investors who participated in the financing include Sofinnova Partners (Capital Fund), KCK Group and Fountain Healthcare Partners.

Jason Hannon, CEO of Mainstay, commented: “A financing of this magnitude, supported by such a quality global investor group, is testament to the confidence in the commercial opportunity for ReActiv8. We are now strongly capitalized to execute on our corporate objectives in 2021 and beyond, including the launch of ReActiv8 in the U.S. market and acceleration of our commercialization efforts in Europe and Australia.”

“This is an exciting time for Mainstay as they bring to market a restorative therapeutic option for patients suffering from disabling chronic low back pain,” said Charles Chon, Partner and Managing Director at Ally Bridge Group, who also joins the Mainstay Medical Board of Directors. “We commend the Company on all the progress it has achieved to-date and look forward to supporting it going forward.”

Cédric Moreau, Partner at Sofinnova Partners, who also joins the Company’s Board of Directors, commented: “We are thrilled to co-lead such a strong syndicate of investors in fuelling Mainstay’s commercial acceleration to make its first-in-class neurostimulation technology available in the U.S. and more extensively worldwide.”

An extraordinary general meeting of Mainstay shareholders was held on 9 February 2021 to approve the financing and related matters. At the EGM, all resolutions were duly passed. The results of the voting on each of the resolutions is available on the Company’s website.

About Mainstay

Mainstay is a medical device company focused on commercializing an innovative implantable restorative neurostimulation system, ReActiv8®, for people with disabling mechanical Chronic Low Back Pain (“CLBP”). The Company is headquartered in Dublin, Ireland and has subsidiaries operating in the United States, Australia, Germany and the Netherlands.

About ReActiv8

ReActiv8 is an active implantable medical device designed to treat adults with intractable chronic low back pain associated with dysfunction of the lumbar multifidus muscle, a key stabilizing muscle of the low back, as evidenced by imaging or physiological testing in adults who have failed therapy, including pain medications and physical therapy, and are not candidates for spine surgery. ReActiv8 provides bilateral electrical stimulation of the L2 medial branch of the dorsal ramus nerve as it crosses the transverse process at L3. This nerve supplies the multifidus muscle to elicit contraction of the muscle which can lead to restoration of control over time, allowing the back to recover from CLBP.

ReActiv8 has a CE Mark allowing for commercialization in the European Economic Area and has been focused on building clinical validation in Germany in select centers ahead of wider commercial availability. ReActiv8 has also been admitted to the Australian Register of Therapeutic Goods (ARTG), enabling commercialization throughout Australia, and has been approved for inclusion on the Protheses List of reimbursed products in Australia, effective as of 1 July 2020. The Prostheses List identifies implantable devices eligible for reimbursement from all private health insurance funds in Australia. In the U.S., ReActiv8 is FDA approved and the Company plans to commercially launch in early 2021.

About Chronic Low Back Pain

One of the root causes of CLBP is impaired control by the nervous system of the muscles that dynamically stabilize the spine. ReActiv8 is designed to electrically stimulate the nerves responsible for contracting these muscles to improve dynamic spine stability, allowing for improvement in CLBP and its disabling effects.

People with CLBP usually have a greatly reduced quality of life and score significantly higher on scales for pain, disability, depression, anxiety and sleep disorders. Their pain and disability can persist despite the best available medical treatments, and only a small percentage of cases result from an identified pathological condition or anatomical defect that may be correctable with spine surgery. Their ability to work or be productive is seriously affected by the condition and the resulting days lost from work, disability benefits and health resource utilization put a significant burden on individuals, families, communities, industry and governments.

Further information can be found at www.mainstay-medical.com

Forward looking statements

This announcement includes statements that are, or may be deemed to be, forward looking statements. These forward looking statements can be identified by the use of forward looking terminology, including the terms “anticipates”, “believes”, “estimates”, “expects”, “intends”, “may”, “plans”, “projects”, “should”, “will”, or “explore” or, in each case, their negative or other variations or comparable terminology, or by discussions of strategy, plans, objectives, goals, future events or intentions. These forward looking statements include all matters that are not historical facts. They appear throughout this announcement and include, but are not limited to, statements regarding the Company’s intentions, beliefs or current expectations concerning, among other things, the Company’s plans to commercialize ReActiv8 in the United States, the U.K., Australia and elsewhere; the commercial performance of ReActiv8; and the Company’s results of operations, financial position, prospects, financing strategies, expectations for product design and development, regulatory applications and approvals, reimbursement arrangements, costs of sales and market penetration and other commercial performance.

By their nature, forward looking statements involve risk and uncertainty because they relate to future events and circumstances. Forward looking statements are not guarantees of future performance, and actual results may differ materially from those described in, or suggested by, the forward looking statements contained in this announcement. In addition, even if future results and developments are consistent with the forward looking statements contained in this announcement, those results or developments may not be indicative of results or developments in subsequent periods. A number of factors could cause results and developments of the Company to differ materially from those expressed or implied by the forward looking statements, including, without limitation, the successful launch and commercialization of ReActiv8, general economic and business conditions, global medical device market conditions, industry trends, competition, the availability and cost of capital, changes in law or regulation, changes in taxation regimes, the time required to commence and complete clinical trials, the time and process required to obtain regulatory approvals, currency fluctuations, changes in its business strategy, and political and economic uncertainty. The forward-looking statements herein speak only at the date of this announcement.

Mainstay Medical Announces Key Strategic Hires to Drive Global Commercial Expansion

Appointments to support upcoming commercial launch of ReActiv8® in the U.S. and foster further growth in Europe and Australia

Mainstay Medical Holdings plc (“Mainstay” or the “Company”) today announced recent senior leadership additions as part of its global commercial strategy. These include: Elias Tu as Vice President of U.S. Sales; Derek Matteo as Vice President of Marketing; James Knibbs as Vice President of UK, Ireland, and Australia; Boris Deutschmann as Country Manager for Germany; Chip Moebus as Vice President of Reimbursement and Market Access; Richard Herman as Vice President of Operations; and Celia Reyes as Vice President of Human Resources.

“We continue to demonstrate the clinical value ReActiv8 brings to patients and are preparing to expand the availability of this compelling therapy in multiple countries. Each of these individuals brings incredible leadership and experience to help build our commercial capabilities, expand in our existing markets, and launch in the U.S.,” commented Jason Hannon, CEO of Mainstay. “Each of them is experienced in bringing disruptive new technologies to the market and will help us deliver ReActiv8 to patients suffering from mechanical chronic low back pain and the physicians treating this condition. Collectively they complement the existing strong leadership we already have and will leverage the deep history of clinical and scientific leadership we’ve developed.”

Appointee Biographies:

Prior to his new role at Mainstay, Elias Tu served as global commercial leader in the neurology division at Philips Healthcare. He also has over 13 years of sales experience at LivaNova, a medical device company specializing in devices used for cardiac surgery and neuromodulation. From 2016 to 2019, Mr. Tu served as Vice President of Sales for Neuromodulation in North America at LivaNova where he attained $350 million in annual sales.

Since 2008, Derek Matteo has led Global Marketing and Global Commercial Development teams in the Orthopedic and Spine healthcare industry. Most recently while at NuVasive, he served as Vice President of Global Technology Commercialization, scaling new innovations in the United States, Latin America, Europe, Australia, and across Asia.

James Knibbs brings extensive experience in sales leadership in implantable devices. He was a Territory Sales Manager at Stryker Instruments, followed by several roles over approximately nine years at Nevro. At Nevro, he rose from Business Development Manager for North UK to UK Country Manager, and ended his time there as Senior Area Director for Western Europe.

Boris Deutschmann possesses over 10 years of experience in the Neuromodulation sector. Previously, he worked at Nevro for over six years, spending the latter part of his time there as Country Manager for Germany and Austria.

Chip Moebus has been in the health care industry for over 20 years serving in multiple roles ranging from field sales leadership to leading teams focused on managed markets and health economics at both Medtronic and Senseonics. Before joining Mainstay Medical, he was part of the senior leadership team at Senseonics where he led commercial and Medicare coverage and payment strategy and execution for the first implantable continuous glucose monitor in the US market.

With over 20 years of field experience in operations management, Richard Herman contributes broad expertise that will be essential for the expansion of operational activities at Mainstay. Previously, he served as Vice President of Global Operational Excellence at Smith & Nephew, a British multinational medical device company. Mr. Herman previously held the position of Senior Director Lean Enterprise of Global Operations at Alere, Inc., a global manufacturer of rapid point-of-care diagnostic tests.

Celia Reyes possesses extensive global Human Resources experience and knowledge in the Life Sciences industry. She served as Executive Human Resources Director at Acadia Pharmaceuticals, Inc., and previously worked as Executive Vice President of Human Resources at Biotix Holdings Inc., as well as other key human resources positions at Millipore Sigma, Roche, and Solvay Pharmaceuticals.

About Mainstay Medical Holdings

Mainstay Medical Holdings is a medical device company focused on commercializing an innovative implantable restorative neurostimulation system, ReActiv8®, for people with disabling mechanical Chronic Low Back Pain (CLBP). The Company is headquartered in Dublin, Ireland and has subsidiaries operating in Ireland, the United States, Australia, Germany and the Netherlands.

About ReActiv8

ReActiv8 is an active implantable medical device designed to treat adults with intractable chronic low back pain associated with dysfunction of the lumbar multifidus muscle, a key stabilizing muscle of the low back, as evidenced by imaging or physiological testing in adults who have failed therapy, including pain medications and physical therapy, and are not candidates for spine surgery. ReActiv8 provides bilateral electrical stimulation of the L2 medial branch of the dorsal ramus nerve as it crosses the transverse process at L3. This nerve supplies the multifidus muscle to elicit contraction of the muscle which can lead to restoration of control over time, allowing the back to recover from CLBP.

ReActiv8 has a CE Mark allowing for commercialization in the European Economic Area and has been focused on building clinical validation in Germany in select centers ahead of wider commercial availability. ReActiv8 has also been admitted to the Australian Register of Therapeutic Goods (ARTG), enabling commercialization throughout Australia, and has been approved for inclusion on the Protheses List of reimbursed products in Australia, effective as of 1 July 2020. The Prostheses List identifies implantable devices eligible for reimbursement from all private health insurance funds in Australia. In the U.S., ReActiv8 is FDA approved and the Company plans to commercially launch in early 2021.

About Chronic Low Back Pain

One of the root causes of CLBP is impaired control by the nervous system of the muscles that dynamically stabilize the spine. ReActiv8 is designed to electrically stimulate the nerves responsible for contracting these muscles to improve dynamic spine stability, allowing for improvement in CLBP and its disabling effects.

People with CLBP usually have a greatly reduced quality of life and score significantly higher on scales for pain, disability, depression, anxiety and sleep disorders. Their pain and disability can persist despite the best available medical treatments, and only a small percentage of cases result from an identified pathological condition or anatomical defect that may be correctable with spine surgery. Their ability to work or be productive is seriously affected by the condition and the resulting days lost from work, disability benefits and health resource utilization put a significant burden on individuals, families, communities, industry and governments.

Further information can be found at www.mainstay-medical.com.

Contacts

PR and IR Enquiries:
LifeSci Advisors, LLC
Brian Ritchie
Tel: + 1 (212) 915-2578
Email: britchie@lifesciadvisors.com

FTI Consulting (for Ireland)
Jonathan Neilan or Patrick Berkery
Tel. : +353 1 765 0886
Email: mainstay@fticonsulting.com

The Ruth Group
Annika Parrish
Tel: +1 (720) 412-9042
Email: aparrish@theruthgroup.com

Mainstay Medical Announces U.S. FDA Approval of ReActiv8® Neurostimulation System for Chronic Low Back Pain

• U.S. commercialization expected to begin in the first half of 2021

• Continues positive momentum for Mainstay, with increasing commercial footprint in Europe and expected launch in Australia in early 2021

Mainstay Medical Holdings plc (“Mainstay” or the “Company”) today announced that the U.S. Food and Drug Administration (FDA) has approved the Company’s Premarket Approval (PMA) application for ReActiv8®, its implantable neurostimulation system to treat intractable chronic low back pain.

Jason Hannon, CEO of Mainstay, said: “I am so proud of our team and the dedicated physicians who managed our clinical trials and cared for their patients. We are thrilled to receive FDA approval of ReActiv8, which is designed to be a restorative treatment and represents a new option for patients suffering with chronic low back pain. This disease affects millions of people around the world, and our clinical data demonstrates that ReActiv8 therapy provides progressive improvements in pain and disability over time, both in magnitude of effect and the proportion of patients who benefit from the treatment. This therapy has the potential to improve quality of life for the most severely-affected patients, and we look forward to making it available to U.S. patients and physicians beginning in the first half of 2021. This will build upon our growing business in Europe and our upcoming launch in Australia.”

“This milestone is the culmination of a development process over many years,” continued Mr. Hannon. “I would like to thank every member of our team, past and present, and in particular our clinical investigators, their teams and clinical study patients for their support and contributions.”

Dr. Chris Gilligan, Chief, Division of Pain Medicine, Department of Anaesthesiology, Perioperative and Pain Medicine, Brigham & Women’s Hospital, Assistant Professor of Anaesthesia, Harvard Medical and Principal Investigator of the pivotal ReActiv8-B study, said: “ReActiv8 fills an important unmet clinical need of patients suffering from chronic low back pain. Patients indicated for ReActiv8 therapy have generally tried numerous other treatments, including physical therapy and pain medications, and many are on long-term opioids to manage their pain. I have seen ReActiv8 provide durable improvements in back pain, the disabling effects of back pain, and quality of life. I am proud to have served as Principal Investigator of this landmark trial, and I look forward to sharing this experience with my physician colleagues who want to start using ReActiv8 in their patients.”

Dr. Robert Levy, a prominent neurosurgeon and pioneer in the field of neuromodulation, commented: “ReActiv8 represents a new treatment category for this severely-affected patient population. The use of neuromodulation to target underlying functional and motor-control issues in patients with musculoskeletal back pain can address a large unmet clinical need. ReActiv8 is designed as a restorative therapy for those suffering from musculoskeletal pain and does not compete with other forms of neuromodulation such as spinal cord stimulation. These patients are difficult for clinicians to treat with current therapy options, which is why so many of them take opioids to manage their pain. Having been part of the neuromodulation field for so long, I am really impressed by this particular innovation and I look forward to its adoption in clinical practice.”

The FDA approval grants Mainstay the right to market ReActiv8 in the United States as an aid in the management of intractable chronic low back pain associated with multifidus muscle dysfunction, as evidenced by imaging or physiological testing in adults who have failed therapy, including pain medications and physical therapy, and are not candidates for spine surgery.

The FDA approval of ReActiv8 is primarily based on results from the ReActiv8-B clinical study, a pivotal 204-patient, international, multi-center, prospective, randomized, active sham-controlled, blinded trial with one-way cross-over, conducted under an Investigational Device Exemption (IDE) from FDA.

Based on the FDA approval, Mainstay is refining its commercial launch plans for ReActiv8 in the U.S., including the build out of the commercial team, inventory procurement and related matters, as well as evaluating the financial resources necessary to fund its planned activities. Mainstay intends to host an investor event later this year to provide an update on its commercial plans for ReActiv8.

About ReActiv8®

ReActiv8 is an active implantable medical device designed to treat people with chronic low back pain (CLBP). ReActiv8 provides bilateral electrical stimulation of the L2 medial branch of the dorsal ramus nerve as it crosses the transverse process at L3. This nerve supplies the lumbar multifidus muscle, a key stabilizing muscle of the low back. Reactiv8’s stimulation of the nerve elicits contraction of the muscle, which can lead to improvement in CLBP and its disabling effects.

Low back pain is the number one cause of years lived with disability worldwide and a leading cause of activity limitation and work absence throughout much of the world, imposing a high economic burden on individuals, families, communities, industry and governments. While treatment options exist for patients with CLBP of a predominantly neuropathic origin, for the large portion of patients whose pain is predominantly nociceptive (or mechanical) in nature there are few therapies beyond drugs and injections, both of which merely mask the pain. ReActiv8 is intended for those patients without indications for spine surgery or spinal cord stimulation and who have continuing pain despite medical management. The Company currently estimates that there are approximately two million people in the EU and the U.S. who could be candidates for ReActiv8.

ReActiv8 has a CE Mark allowing for commercialization in the European Economic Area and has been focused on building clinical validation in Germany in select centers ahead of wider commercial availability in the future. ReActiv8 has also been admitted to the Australian Register of Therapeutic Goods (ARTG), enabling commercialization throughout Australia, and has been approved for inclusion on the Protheses List of reimbursed products in Australia, effective as of 1 July 2020. The Prostheses List identifies implantable devices eligible for reimbursement from all private health insurance funds in Australia. In the U.S., ReActiv8 is FDA approved, and the Company plans to commercially launch in early 2021.

About Mainstay Medical Holdings

Mainstay Medical Holdings is a medical device company focused on commercializing an innovative implantable restorative neurostimulation system, ReActiv8®, for people with disabling Chronic Low Back Pain (CLBP). The Company is headquartered in Dublin, Ireland and has subsidiaries operating in Ireland, the United States, Australia, Germany and the Netherlands.

About the ReActiv8-B Clinical Trial

Mainstay submitted the PMA application to the FDA based upon the totality of its clinical data for ReActiv8. The pivotal clinical trial upon which the PMA submission was based is the ReActiv8-B study. The ReActiv8-B clinical trial is an international, multi-center, prospective, randomized, active sham-controlled, blinded trial with one-way cross-over, conducted under an Investigational Device Exemption (IDE) from the FDA. A total of 204 patients with chronic low back pain refractory to physical therapy and medical management were implanted with ReActiv8 at leading clinical sites in the U.S., Europe and Australia and randomized 1:1 to therapy or control. In the treatment group, the ReActiv8 pulse generator was programmed to deliver electrical stimulation expected to elicit episodic contractions of the multifidus muscle. In the control group, the ReActiv8 device was programmed to provide a low level of electrical stimulation. Following assessment of the primary endpoint at 120 days, patients in the control group crossed over to receive levels of electrical stimulation similar to those in the treatment group. Information about the study can be found at https://clinicaltrials.gov/ct2/show/study/NCT02577354.

About Chronic Low Back Pain

One of the root causes of CLBP is impaired control by the nervous system of the muscles that dynamically stabilize the spine. ReActiv8 is designed to electrically stimulate the nerves responsible for contracting these muscles to improve dynamic spine stability, allowing for improvement in CLBP and its disabling effects.

People with CLBP usually have a greatly reduced quality of life and score significantly higher on scales for pain, disability, depression, anxiety and sleep disorders. Their pain and disability can persist despite the best available medical treatments, and only a small percentage of cases result from an identified pathological condition or anatomical defect that may be correctable with spine surgery. Their ability to work or be productive is seriously affected by the condition and the resulting days lost from work, disability benefits and health resource utilization put a significant burden on individuals, families, communities, industry and governments.

Further information can be found at www.mainstay-medical.com

Mainstay Medical Announces Reimbursement Approval for ReActiv8 in Australia

Mainstay Medical Holdings plc (“Mainstay” or the “Company”), today announced that ReActiv8, its implantable restorative neurostimulation system to treat disabling Chronic Low Back Pain, has been approved for inclusion in the Prostheses List of reimbursed products in Australia, effective as of 1 July 2020. The Prostheses List identifies implantable devices eligible for reimbursement from all private health insurance funds in Australia. This approval follows the December 2019 regulatory approval from the Australian Therapeutic Goods Administration (TGA) for ReActiv8, which confirmed the inclusion of ReActiv8 in the Australian Register of Therapeutic Goods (ARTG), enabling commercialization throughout Australia.

Jason Hannon, CEO of Mainstay, said: “We continue to demonstrate the clinical value of ReActiv8 to patients suffering from Chronic Low Back Pain. Our growing body of evidence from clinical studies performed to date, as well as our early commercial experience in Germany, shows the substantial restorative benefits patients are receiving. We are delighted to be included in the Prostheses List, enabling us to deliver this valuable therapy to Australian physicians and patients. Several top Australian physicians have been part of our clinical studies since inception and are among the most experienced globally in selecting and treating patients with ReActiv8. We look forward to providing commercial availability of ReActiv8 to these physicians and their peers across Australia, which we intend to begin in early 2021.”

About ReActiv8

ReActiv8 is an active implantable medical device designed to treat people with chronic low back pain (CLBP). ReActiv8 electrically stimulates the nerves that supply the lumbar multifidus muscle, a key stabilizing muscle of the low back, to elicit contraction of the muscle which can lead to restoration of control over time, allowing the back to recover from CLBP.

Low back pain is the number one cause of years lived with disability worldwide and is a leading cause of activity limitation and work absence throughout much of the world, imposing a high economic burden on individuals, families, communities, industry, and governments. While treatment options exist for patients with CLBP of a predominantly neuropathic origin, for the large portion of patients whose pain is predominantly nociceptive (or mechanical) in nature there are few therapies beyond drugs and injections, both of which offer temporary relief at best. ReActiv8 is intended for those patients without indications for spine surgery or spinal cord stimulation and who have continuing pain despite medical management. The Company estimates that there are approximately two million people in the EU and the U.S. alone who could be candidates for ReActiv8 today.

ReActiv8 has a CE Mark allowing for commercialization in the European Economic Area and has been focused on building clinical validation in Germany in select centers ahead of wider commercial availability in the future. The Company submitted the final module of its Pre-Market Approval (PMA) application to the U.S. FDA relating to ReActiv8 in August 2019, and it expects an approval decision around the end of 2020.

Mainstay Medical Announces Completion of Day 100 Meeting with FDA Regarding Pre-Market Approval (PMA) Application for ReActiv8

Mainstay Medical International plc (“Mainstay” or the “Company”, Euronext Paris: MSTY.PA and Euronext Growth operated by Euronext Dublin (MSTY.IE), a medical device company focused on bringing to market ReActiv8, an implantable restorative neurostimulation system to treat disabling Chronic Low Back Pain, today announced that on 10 December 2019 the Company completed a Day 100 meeting with the U.S. Food and Drug Administration (FDA) regarding a Pre-Market Approval (PMA) application submission for ReActiv8.

Jason Hannon, CEO of Mainstay, said: “We appreciate the opportunity to meet with FDA to discuss their review of the data we included in the PMA. The productive dialogue will help us submit an amendment to the PMA to reflect FDA’s feedback. We continue to expect a decision regarding approval around the end of 2020.”

FDA generally meets with the PMA sponsor approximately 100 days after filing of the PMA for the purpose of discussing the status of the review of the application. Prior to the meeting, FDA provided Mainstay with its initial feedback on the PMA, consisting of questions regarding the data included in the PMA and the interpretation of such data. The Company currently has no plans to conduct another premarket pivotal IDE trial for ReActiv8.

Mainstay will include the information requested by FDA in an amendment to the PMA, which the Company expects to file in the first quarter of 2020.

Mainstay Medical Announces Regulatory Approval from Australian Therapeutic Goods Administration (TGA) for ReActiv8

Application for inclusion on Australian Prostheses List for private reimbursement planned for first quarter of 2020, with an approval decision expected in the third quarter of 2020.

Mainstay Medical International plc (“Mainstay” or the “Company”, Euronext Paris: MSTY.PA and Euronext Growth operated by Euronext Dublin (MSTY.IE), today announced that it has received regulatory approval from the Australian Therapeutic Goods Administration (TGA) for ReActiv8, its implantable restorative neurostimulation system to treat disabling Chronic Low Back Pain. This approval confirms admission of ReActiv8 to the Australian Register of Therapeutic Goods (ARTG), enabling commercialization throughout Australia.

Jason Hannon, CEO of Mainstay, said: “We are excited to receive TGA approval and take the next step toward making ReActiv8 available to patients in Australia. Australian physicians who have been part of our clinical studies to date are among the most experienced globally in selecting and treating patients with ReActiv8 therapy. The clinical data in support of ReActiv8 continues to build and was instrumental in demonstrating to TGA that ReActiv8 is a valuable therapy that should be available to Australian patients. This approval was received ahead of our expected timeline, and we will now move to the next step in the process, which is applying for inclusion of Reactiv8 on the Prostheses List. We plan to launch ReActiv8 commercially after securing a place on the Prostheses List.”

The Company plans to submit an application for ReActiv8 to be included in the Prostheses List of reimbursed products, with a reimbursement decision expected in the third quarter of 2020. The Prostheses List identifies implantable devices eligible for reimbursement from all private health insurance funds in Australia.

About ReActiv8

ReActiv8 is an active implantable medical device designed to treat people with chronic low back pain (CLBP). ReActiv8 electrically stimulates the nerves that supply the lumbar multifidus muscle, a key stabilizing muscle of the low back, to elicit contraction of the muscle which can lead to restoration of control over time, allowing the back to recover from CLBP.

Low back pain is the number one cause of years lived with disability worldwide and is a leading cause of activity limitation and work absence throughout much of the world, imposing a high economic burden on individuals, families, communities, industry, and governments. While treatment options exist for patients with CLBP of a predominantly neuropathic origin, for the large portion of patients whose pain is predmoniantly nociceptive (or mechanical) in nature there are few therapies beyond drugs and injections, both of which offer temporary relief at best.

ReActiv8 is intended for those patients without indications for spine surgery or spinal cord stimulation and who have continuing pain despite medical management. The Company estimates that there are approximately two million people in the EU and the U.S. alone who could be candidates for ReActiv8 today.

ReActiv8 has a CE Mark allowing for commercialization in the European Economic Area and has been focused on building clinical validation in Germany in select centers ahead of wider commercial availability in the future. The Company submitted the final module of its Pre-Market Approval (PMA) application to the U.S. FDA relating to ReActiv8 in August 2019, and it expects an approval decision around the end of 2020.

Mainstay Medical Announces Acceptance For Filing by US FDA Of Pre-Market Approval (PMA) Application for ReActiv8

Mainstay Medical International plc (“Mainstay” or the “Company”, Euronext Paris: MSTY.PA and Euronext Growth of Euronext Dublin: MSTY.IE), a medical device company focused on bringing to market ReActiv8®, an implantable neurostimulation system to treat disabling Chronic Low Back Pain, today announces that the U.S. Food and Drug Administration (FDA) has accepted for filing the Company’s Pre-Market Approval (PMA) application for ReActiv8.

Mainstay submitted the PMA to the FDA in August. By regulation, the FDA will notify the applicant whether the PMA has been accepted for filing within 45 days after submission. By accepting the Company’s PMA for filing, the FDA has made a threshold determination that the application is sufficiently complete to begin an in-depth review. Mainstay continues to expect a decision on approval around the end of 2020.

About Mainstay

Mainstay is a medical device company focused on commercializing an innovative implantable restorative neurostimulation system, ReActiv8®, for people with disabling Chronic Low Back Pain (CLBP). The Company is headquartered in Dublin, Ireland. It has subsidiaries operating in Ireland, the United States, Australia, Germany and the Netherlands, and is listed on regulated market of the Euronext Paris (MSTY.PA) and the Euronext Growth market of Euronext Dublin (MSTY.IE).

About Chronic Low Back Pain

One of the root causes of CLBP is impaired control by the nervous system of the muscles that dynamically stabilize the spine. ReActiv8 is designed to electrically stimulate the nerves responsible for contracting these muscles to improve dynamic spine stability, allowing the body to recover from CLBP.

People with CLBP usually have a greatly reduced quality of life and score significantly higher on scales for pain, disability, depression, anxiety and sleep disorders. Their pain and disability can persist despite the best available medical treatments, and only a small percentage of cases result from an identified pathological condition or anatomical defect that may be correctable with spine surgery. Their ability to work or be productive is seriously affected by the condition and the resulting days lost from work, disability benefits and health resource utilization put a significant burden on individuals, families, communities, industry and governments.

Further information can be found at www.mainstay-medical.com

CAUTION – in the United States, ReActiv8 is limited by federal law to investigational use only.

Mainstay Medical Provides Company Update and Reports 2019 Half Year Financial Results

ReActiv8 Pre-Market Approval (PMA) application submitted to U.S. FDA in August 2019; acceptance for FDA review expected October 2019

European commercial validation efforts continue to progress

Successful completion of financing transactions providing approximately $28 million of cash runway extension

Mainstay Medical International plc (“Mainstay” or the “Company”, Euronext Paris: MSTY.PA and Euronext Growth of Euronext Dublin: MSTY.IE), a medical device company focused on bringing to market ReActiv8®, an implantable neurostimulation system to treat disabling Chronic Low Back Pain, today provides a company update and reports its financial results for the half year ended 30 June 2019.

Jason Hannon, CEO of Mainstay, said: “We continue to make significant progress on our key corporate objectives of pursuing regulatory approval in the U.S. and advancing the commercial validation effort in Germany and other select European markets. I am pleased to report that we submitted the pre-market approval (PMA) application for ReActiv8 to the U.S. Food and Drug Administration (FDA) in August. Pending the FDA’s acceptance of the PMA for review, anticipated in October 2019, we expect a decision regarding approval around the end of 2020. We also continue to make progress working with key physician partners in Germany who are incorporating ReActiv8 into their practices in order to validate commercial adoption, refine patient selection strategies and follow ongoing patient progress.”

Business Update

• In August 2019, Mainstay submitted the PMA application to the FDA based upon the totality of its clinical data for ReActiv8. Pending acceptance of the submission by the FDA, anticipated in October 2019, a decision regarding approval is expected around the end of 2020. The pivotal clinical trial upon which the PMA submission was based is the 204-patient ReActiv8-B clinical study. A summary of the clinical trial results is as follows:

  • The primary efficacy endpoint of the study was a comparison of responder rates between the treatment and control groups as measured on the visual analog scale (VAS) of pain, with responders defined as having a 30% or greater improvement on this measure between baseline and 120 days after randomization, without any increase in pain medication and/or muscle relaxants taken in the two weeks prior to the primary endpoint assessment visit. In the treatment group the responder rate at 120 days was 57%, compared to 47% in the control group, resulting in a difference that is not statistically significant.

  • The protocol included a pre-specified analysis of the primary endpoint data examining the cumulative proportion of responders, which is a comparison of ranks and inherently preserves information over a dichotomized endpoint, thereby improving statistical power. In that analysis, a statistically significant difference between the treatment and control groups was demonstrated, with the treatment group showing a higher proportion of responders across all threshold levels.

  • The protocol also included a pre-specified analysis of the primary endpoint where Mainstay adjusted for patients who increased their pain medications for reasons unrelated to their back pain. In that analysis, the responder rate at 120 days in the treatment group was 61%, compared to 47% in the control group, resulting in a difference that is statistically significant.

  • Statistically significant differences on a number of key secondary endpoints and supplemental analyses were observed in the treatment group as compared to the control group at 120 days, including reduction from baseline in pain as measured by both mean reduction in VAS and percent of pain relief (PPR), change from baseline in disability measured by the Oswestry Disability Index (ODI), change from baseline in quality of life measured by the European Quality of Life Score on Five Dimensions (EQ-5D), subject global impression of change (SGIC), clinician global impression of change (CGI) and patient treatment satisfaction as measured by the treatment satisfaction questionnaire (TSQ).

  • Improvements in the percentage of patients reporting pain reduction continued beyond the 120-day assessment through one year for both groups. The percentage of the 160 patients in the treatment and control groups that had completed the one-year assessment having a 30% or greater reduction in low back pain VAS at that assessment without a significant increase in pain medication was 66%. These data are subject to change as the remaining patients reach the one-year assessment.

  • The protocol permitted patients to adjust their back pain medication usage after the 120-day assessment point. At one year, 49% of the 61 patients in both groups combined who were on opioids at baseline had discontinued or decreased their use of opioids. These results are subject to change as the remaining patients reach the one-year assessment.

  • The incidence and type of adverse events (AEs), including serious AEs, compares favorably to that of spinal cord stimulator devices, with no unanticipated AEs related to the device, procedure or stimulation.

• In Germany, Mainstay’s initial European market, the Company’s re-focusing of its commercial validation efforts was undertaken throughout 2018. Mainstay is now solely dedicated to building a small number of reference sites where high volumes of patients are treated with ReActiv8, allowing the Company to gather associated clinical data, refine patient selection processes for commercial markets, and gain the learnings needed to accelerate commercial launch in future markets.

Financial Update

• Since the beginning of 2019, Mainstay has conducted financing activities that have resulted in approximately $28 million of cash runway extension:

• On 29 July 2019, Mainstay completed financing transactions consisting of the issuance of 4,649,775 new ordinary shares at a purchase price of €3.00 per share and the drawdown of €3.0 million in additional debt from the Company’s existing lender, IPF Partners, resulting in aggregate gross proceeds of €16.9 million (US$18.9 million).

• On 18 April 2019, Mainstay and its subsidiary, Mainstay Medical Limited, entered into an amendment to their agreement with IPF Partners relating to the existing debt facility. Pursuant to the amendment:

  • The repayment schedule for the three existing tranches drawn under the debt facility was amended such that no principal or interest will be repaid until 2021, with the principal and accrued interest to be amortized over the period from January 1, 2021 through September 30, 2023.

  • A new tranche of €3.0 million (approximately $3.34 million) was made available to Mainstay, which was drawn down by Mainstay on 29 July 2019. The repayment schedule for the new tranche will be the same as the amended repayment schedule for the three existing tranches.

  • The interest rate for all tranches will be 8% per annum, with interest accruing but capitalized prior to January 1, 2021. The interest rates previously applicable to the initial three tranches ranged from 10.5% to 12.5%.

  • The 5% repayment fee applicable to each existing tranche was eliminated.

  • All principal and accrued interest from all tranches will automatically convert into ordinary shares of the Company at a price per share of €8 upon the earlier of (a) FDA approval of Mainstay’s PMA application for ReActiv8, (b) the date by which at least 900,000 ordinary shares of the Company are publicly sold on-market by non-affiliates of Mainstay since April 2019 at a price per share of at least €8, or (c) IPF Partners’ election to undertake such conversion, in each case unless the Company elects to satisfy such obligation in whole or in part in cash.

  • The minimum cash covenant was amended so that Mainstay is required to hold cash at least equal to its projected cash expenditures for operations and debt repayment for the next three months, and the covenant relating to the achievement of commercial milestones was eliminated.

  • Mainstay issued to IPF Partners warrants to purchase 1.5 million of its ordinary shares at a price per share of €6 at any time prior to the 6th anniversary of the amendment date.

• Revenue during the six-month period ended 30 June 2019 was $0.6 million ($0.36 million in 1H18).

• Operating expenses for the six-month period ended 30 June 2019 were $9.5 million ($15.8 million in 1H18). The decrease was driven primarily by reduced costs relating to activities for the ReActiv-8 B clinical trial following the completion of all implants, as well as a decrease in payroll related costs following a reduction in headcount within 2019.

• Cash on hand as at 30 June 2019 was $5.8 million (31 December 2018: $29.7 million). Cash on hand at 31 July 2019 was $23.5 million.

Details of ReActiv8-B Clinical Trial

The ReActiv8-B clinical trial is an international, multi-center, prospective, randomized, active sham-controlled, blinded trial with one-way cross-over, conducted under an IDE from the FDA. A total of 204 patients with chronic low back pain refractory to physical therapy were implanted with ReActiv8 at leading clinical sites in the U.S., Europe and Australia and randomized 1:1 to therapy or control. In the treatment group, the ReActiv8 pulse generator was programmed to deliver electrical stimulation expected to elicit episodic contractions of the multifidus muscle. In the control group, the ReActiv8 device was programmed to provide a low level of electrical stimulation. Following assessment of the primary endpoint at 120 days, patients in the control group crossed-over to receive levels of electrical stimulation similar to those in the treatment group. The FDA’s review of the PMA may result in the FDA not agreeing with Mainstay’s interpretation of its clinical data, including whether statistical significance was achieved for one or more endpoints.

About Mainstay

Mainstay is a medical device company focused on commercializing an innovative implantable restorative neurostimulation system, ReActiv8®, for people with disabling Chronic Low Back Pain (CLBP). The Company is headquartered in Dublin, Ireland. It has subsidiaries operating in Ireland, the United States, Australia, Germany and the Netherlands, and is listed on regulated market of the Euronext Paris (MSTY.PA) and the Euronext Growth market of Euronext Dublin (MSTY.IE).

About Chronic Low Back Pain

One of the root causes of CLBP is impaired control by the nervous system of the muscles that dynamically stabilize the spine. ReActiv8 is designed to electrically stimulate the nerves responsible for contracting these muscles to improve dynamic spine stability, allowing the body to recover from CLBP.

People with CLBP usually have a greatly reduced quality of life and score significantly higher on scales for pain, disability, depression, anxiety and sleep disorders. Their pain and disability can persist despite the best available medical treatments, and only a small percentage of cases result from an identified pathological condition or anatomical defect that may be correctable with spine surgery. Their ability to work or be productive is seriously affected by the condition and the resulting days lost from work, disability benefits and health resource utilization put a significant burden on individuals, families, communities, industry and governments.

Further information can be found at www.mainstay-medical.com