Mainstay Medical Full Year 2015 Preliminary Results and Business Update

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 the publication of preliminary results for the year ended 31 December 2015.


Business Highlights

We continue to make progress towards commercialization of ReActiv8. On 2 November 2015 we announced that we had submitted an application for CE Marking to our Notified Body. We have since had several interactions with the Notified Body to progress the application.

Following CE Marking, we plan to commence commercialization in Germany, our first target market. Preparations for commercialization are ongoing, including interaction with initial physician customers, and recruiting direct sales and support staff. In Germany we plan to use a small direct sales force to focus on a select group of multi-disciplinary centers who see a large number of people with CLBP. As we gain experience with this commercialization strategy, we will consider expanding to additional customers and additional countries.

Positive results of the ReActiv8-A Clinical Trial were announced on 31 August 2015, and on 4 December 2015 we announced additional data confirming the positive results from this clinical trial. These results were presented at the scientific meeting of the North American Neuromodulation Society in December by Professor Sam Eldabe (Middlesbrough, UK), an investigator in the ReActiv8- A Clinical Trial. ReActiv8 also featured in a number of other presentations on back pain presented by leading neuromodulation physicians at this meeting.

On 29 May 2015, we announced FDA approval to begin the ReActiv8-B Clinical Trial under an Investigational Device Exemption (IDE). We have since worked with the FDA to refine the protocol, and we are progressing clinical trial site selection and initiation, physician training, and submissions to Ethics Committees (Institutional Review Boards (IRBs) in the US). The ReActiv8-B Clinical Trial is designed to generate data to form part of the Pre-Market Approval Application (PMAA) of ReActiv8 to the FDA. Following Pre-Market Approval (if obtained), we plan to commercialize ReActiv8 in the US.

The ReActiv8-B Clinical Trial is an international, multi-center, prospective randomized sham controlled blinded trial with one-way crossover. In summary, eligible subjects will have baseline data collected and then following verification that the enrolment criteria are met, ReActiv8 will be implanted. At the 14-day post implant follow up visit, half the subjects will be randomized to receive appropriately programmed stimulation (the treatment arm), and half will be randomized to receive minimal stimulation (the control arm). Subjects will not be informed about their allocation to the treatment or control arm, and all subjects will be told that they may or may not feel something with stimulation, and all will be encouraged to continue using ReActiv8 at least until the 120-day primary outcome assessment visit. Subjects will be instructed to not use any other therapies for CLBP from the time of enrolment until after data collection at the primary outcome assessment visit. Subjects will also be instructed to keep constant the use of medications prescribed and used for low back pain until the primary outcome assessment visit. The primary efficacy endpoint of the Trial is a comparison of responder rates between the treatment and control arms. The Trial will be considered a success if there is a statistically significant difference in responder rates between the treatment and control arms. A responder is defined as having at least a 30% improvement in low back pain reported on a 100mm Visual Analog Scale (VAS) between baseline and the 120-day primary outcome assessment visit, with no increase in medications prescribed and taken for pain in the 14 days prior to the visit. Data for multiple secondary outcome measures will also be gathered. After the primary outcome assessment visit, subjects in the control arm will be crossed over to receive appropriately programmed full strength stimulation, and all subjects will continue to be followed.

The statistical design of the Trial requires data from 128 subjects at the 120-day primary outcome assessment visit. Additional subjects will likely be enrolled and implanted as part of the surgical roll-in phase and to achieve data from 128 subjects in the pivotal cohort. The Trial is designed with an “interim look” when primary outcome data are available from half the subjects, and if necessary the number of subjects in the pivotal cohort may be increased to achieve the targeted statistical significance. Up to 40 clinical trial sites may be involved in the Trial, some of which may be referring sites and some may be implanting sites.

A summary of the protocol can be found at

Based on our experience with enrolment in the ReActiv8-A Trial, we estimate that full enrolment of the pivotal cohort in the ReActiv8-B Trial will take 12-18 months from ramp up of enrolment, with results anticipated to be available approximately six months following full enrolment. The work required to complete a PMAA submission to the FDA is estimated to take approximately six months from data availability.

The ReActiv8-B Trial, if successful, will provide what is referred to as Level 1 Evidence of safety and efficacy of ReActiv8, and Level 1 evidence may be used to support applications for favourable reimbursement in the US.

We plan to ramp up enrolment in the ReActiv8-B Trial once we determine that we have sufficient financial resources to complete the Trial through data availability. A small number of subjects may be enrolled in the ReActiv8-B Trial prior to securing such financial resources.

We are also pleased to announce the issuance of two new U.S. Patents, bringing the total current number of issued U.S. issued Patents in the Mainstay portfolio to seven:

  • U.S. Patent No. 9,186,501 entitled “Systems and Methods for Implanting Electrode Leads for Use with Implantable Neuromuscular Electrical Stimulator”; and
  • U.S. Patent No. 9,248,278 entitled “Modular Stimulator for Treatment of Back Pain, Implantable RF Ablation System and Methods of Use”.

Corresponding applications have been filed for other countries. Mainstay continues to add to its portfolio of issued patents and pending patent applications.


Financial Update

On 24 August 2015, we announced the closing of debt financing for up to $15 million. The secured debt facility is non-dilutive to existing shareholders, and is being provided by IPF Partners, a leading financing provider focused on the European healthcare sector. As at 31 December 2015, the Group had drawn down $10.5 million. The last tranche of $4.5 million can be drawn down at the Company’s discretion up to 31 July 2016 following CE Marking approval of ReActiv8.

Operating expenses were $12.9 million for the year and have decreased by $2.3 million compared to 2014 due to costs associated with the European IPO included in 2014 not arising in 2015, offset by costs related to the expansion of the Mainstay team.

Cash on hand at 31 December 2015 was $16.6 million and operating cash outflows for 2015 were $11.6 million.


Outlook and future developments

While we await CE Marking approval for ReActiv8, we are preparing for commercialization in Europe. We are also preparing for the ReActiv8-B Clinical Trial and, subject to the availability of sufficient financial resources, we look forward to ramping up enrolment in the Trial.

The principal risks and uncertainties faced by the Group remain substantially unchanged from the disclosures included in the 2014 Annual Report. Those risks and uncertainties should be read in conjunction with this announcement and the Company’s press releases and other public disclosures (copies of which can be found on the Company’s website) and could cause actual events to differ materially from those described in this announcement and our disclosures.

Mainstay is a medical device company focused on bringing to market an innovative implantable 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 and Australia, and is listed on Euronext Paris (MSTY.PA) and the ESM of the Irish Stock Exchange (MSTY.IE).


About the ReActiv8-A Trial

The ReActiv8-A Clinical Trial is a prospective single arm clinical trial with up to 96 subjects at sites in Australia and Europe. Data from the first 47 subjects in ReActiv8-A Trial have been submitted as part of an application for CE Marking. Further details can be obtained at


About the ReActiv8-B Trial

The ReActiv8-B Clinical Trial is an international, multi-center, prospective randomized sham controlled blinded trial with one-way crossover conducted under an Investigational Device Exemption (IDE). The ReActiv8-B Clinical Trial is designed to generate data to form part of the Pre-Market Approval Application (PMAA) of ReActiv8 to the FDA. Further details can be found at


About Chronic Low Back Pain (CLBP)

One of the recognised root causes of CLBP is disruption of control by the nervous system of the muscles that dynamically stabilise the spine in the lower back, and an unstable spine can result in back pain. ReActiv8 is designed to electrically stimulate the nerves responsible for contracting these muscles and thereby help to restore muscle control and 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 CLBP and the resulting days lost from work, disability benefits and health resource utilisation put a significant burden on individuals, families, communities, industry, and governments.

Further information can be found at

ReActiv8 is an investigational device and is not approved for commercialization anywhere in the world. CAUTION – in the United States, ReActiv8 is limited by federal law to investigational use only