Mainstay Medical Expands Clinical Trial of ReActiv8® for People with Chronic Low Back Pain to the United Kingdom

Regulatory News:

Mainstay Medical International plc (Euronext Paris: MSTY.PA and ESM of the Irish Stock Exchange: MSTY.IE) announces that it has received authorization from the Medicines and Healthcare Products Regulatory Agency (MHRA) and the Central Ethics Committee to expand the clinical trial of ReActiv8, its innovative implantable neurostimulation device for the treatment of people with Chronic Low Back Pain, to include clinical trial sites in the United Kingdom. Enrolment of subjects is commencing in these additional sites. Two of these sites also participated in the European Feasibility Study, results of which were presented in mid-2013.

Mr. Peter Crosby, Mainstay’s Chief Executive Officer, noted "We are pleased to expand the clinical trial to the UK sites as planned. This continues our steady progress towards regulatory approval and commercialization of ReActiv8. When available, ReActiv8 has the potential to change the lives of the millions of people who suffer from Chronic Low Back Pain.”

The clinical trial of ReActiv8 started in March 2014, and several sites in Australia and Belgium continue to actively enrol subjects. The purpose of the clinical trial is to investigate ReActiv8 as a treatment for adults with debilitating Chronic Low Back Pain who have few other treatment options. More details of the clinical trial, including identification of active investigation sites, can be found at www.clinicaltrials.gov/show/NCT01985230.

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About Mainstay

Mainstay is a medical device company which is developing an innovative implantable neurostimulation medical device, ReActiv8, for people with debilitating Chronic Low Back Pain (CLBP). Low Back Pain is the leading cause of activity limitation and work absence throughout much of the developed world, imposing a high economic burden on individuals, families, communities, industry, and governments.

The Company is headquartered in Dublin, Ireland. It has subsidiaries operating in Ireland, the United States and Australia, and is listed on Euronext Paris and the ESM of the Irish Stock Exchange.

About Chronic Low Back Pain

One of the recognised root causes of CLBP is impaired control by the nervous system of the muscles that stabilize the spine in the lower back, and an unstable spine can lead to back pain. ReActiv8 is designed to electrically stimulate the nerves responsible for contracting these muscles and thereby help to restore muscle control and improve spine stability, allowing the body to recover from CLBP.

People with debilitating 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 spinal 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 utilisation put a significant burden on economies.

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

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