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.