Positive Results for Mainstay Medical’s Clinical Trial of ReActiv8

Clinically important, statistically significant, and lasting improvement in pain, disability, and quality of life for people with Chronic Low Back Pain and limited treatment options

63% of people with clinically important improvement in back pain; and 72% with clinically important improvement in back pain in the cohort with no financial compensation related to back pain

Dublin, Ireland – Mainstay Medical International plc (Mainstay or the Company, listed on Euronext Paris: MSTY.PA and ESM of the Irish Stock Exchange: MSTY.IE), a medical device company focused on bringing to market ReActiv8®, a new implantable neurostimulation system to treat disabling Chronic Low Back Pain (CLBP), today announced results from the ReActiv8-A Clinical Trial, an international, multi-centre, prospective, single arm trial to gather data for a submission for CE Marking for ReActiv8. The ReActiv8-A Trial shows clinically important, statistically significant and lasting improvement in pain, disability and quality of life in this clinically challenging population.

ReActiv8 is for treatment of people who suffer from CLBP, have attempted most or all available treatment options, and are not candidates for back surgery or spinal cord stimulation. The ReActiv8-A Trial population was relatively young (mean age 43.9 years) and had a long history of low back pain (mean 13.8 years). All of the subjects had attempted physical therapy, and 70% were taking opioids for back pain. The results presented are based on data from the first 47 subjects implanted in the ReActiv8-A Trial of whom 46 have reached the 90 day follow up and to date 33 have reached the 180 day follow up.

Results highlights:

  • Clinical performance of ReActiv8 at 90 days compared to baseline for all subjects is:
    • 63% with clinically important improvement in back pain defined as ≥2 point reduction on the 0-10 Numerical Rating Scale (NRS) for low back pain1 measured on the day.
    • 54% responder rate for pain: A responder is defined as a subject with a clinically important improvement in mean of prior 7 days NRS with no clinically significant increase in medications taken for low back pain.
    • 57% with a clinically important improvement1 in disability on the Oswestry Disability Index (ODI).
    • 67% with a clinically important improvement2 in quality of life on the EQ-5D scale.
  • Clinical performance at 90 days is even better for the group of subjects who do not receive financial compensation for being out of work due to their back pain. For those 32 subjects the results are:
    • 72% with clinically important improvement in low back pain NRS on the day.
    • 66% responder rate for pain.
    • 63% with clinically important improvement in ODI.
    • 69% with a clinically important improvement in EQ-5D (90% at 180 days).
  • Improvements in low back pain, disability and quality of life were generally consistent or improved at 180 days (n=33). Paired data for all subjects at 90 and 180 days respectively are:
    • 63% and 58% with clinically important improvement in low back pain NRS on the day.
    • 57% and 58% with clinically important improvement in ODI.
    • 67% and 79% with clinically important improvement in EQ-5D
    • 61% and 64% reported >50% Percent Pain Relief.

Adverse Events (AEs) incidence and type were comparable to AEs in clinical trials reported for other neurostimulation devices, with no unanticipated AEs and no serious AEs related to the device, therapy or procedure.

  • The observed lead migration incidence (<1%) demonstrates that the ReActiv8 lead mitigates the risk of lead migration identified with commercially available neurostimulation leads in the earlier Feasibility Trial.
  • The incidence of surgical revision (19%) to date is within the range published for other neurostimulation systems. Mainstay has identified a modification to the implant technique which it believes has the potential to reduce revision rates.

A full description of the ReActiv8-A Trial and results is provided below.

The Chairman of the ReActiv8-A Data Monitoring Committee is Professor Chris Gilligan, Chief of the Division of Pain Medicine and Co-Director of the Spine Center at the Beth Israel Deaconess Medical Center of the Harvard Medical School. Commenting on the positive results he said: “As physicians we struggle to provide solutions for people with chronic low back pain. The results from this clinical trial open the prospect of a new treatment option for clinicians and significant benefit for people suffering from chronic low back pain.”

Mainstay estimates that there are over two million people in the US and EU who could be candidates for treatment with ReActiv8. They are people with CLBP, in whom the root cause of the persistence of pain is disruption in control of the key muscles that stabilize the lumbar spine, particularly the lumbar multifidus. ReActiv8 is designed to deliver episodic electrical stimulation to nerves that cause these muscles to contract, helping to restore stability, and thus allowing recovery from CLBP.

ReActiv8 is not spinal cord stimulation. SCS targets different clinical conditions and delivers electrical stimulation to interfere with the perception of pain, without addressing the root cause. The market for SCS is estimated to be approximately $1.4Bn in 2015 or approximately 100,000 patients.

Dr. Marc Russo, Director of the Hunter Pain Clinic in Newcastle, Australia and investigator in the Trial said: “It was pleasing to see ReActiv8 have such an impact on people’s quality of life after so many other conventional treatments have been unsuccessful for such a long time.”

Peter Crosby, CEO of Mainstay, added: “The results from the ReActiv8-A Trial show improvements which are better than any other therapy for this group of people as reported in the literature. We are excited that our unique approach to treating this type of chronic low back pain offers the potential to change the lives of millions of people worldwide who have no effective treatment alternative.”

The Company believes that data from the subjects reported may be sufficient to apply for a CE Mark for ReActiv8, and is engaging with its notified body about the Company’s submission for CE Marking.

Subjects continue to be enrolled in the ReActiv8-A Trial to gather additional data on performance and safety which the Company plans to incorporate into the Post Market Clinical Follow Up.