NMT Medical's MIST Study Indicates That Closing a PFO Has an Effect on Migraine Monday March 13, 9:15 am ET First Prospective, Randomized Study Misses Endpoints But Shows Positive Treatment Effect; NMT to Incorporate Data From MIST Into Other Studies
ATLANTA, March 13 /PRNewswire-FirstCall/-- NMT Medical, Inc. (Nasdaq: NMTI - News), an advanced medical technology company that designs, develops, manufactures and markets proprietary implant technologies that allow interventional cardiologists to treat cardiac sources of migraine headaches, stroke and other potential brain attacks, today announced results of its MIST (Migraine Intervention with STARFlex® Technology) study at the American College of Cardiology's 55th Annual Scientific, Late-Breaking Clinical Trials Sessions. ADVERTISEMENT
Doctors Peter Wilmshurst and Andrew Dowson, co-primary investigators of MIST, jointly presented the results this morning. Dr. Wilmshurst is Consultant Cardiologist at Royal Shrewsbury Hospital, Shrewsbury. Dr. Dowson is Director of the King's Headache Service, Kings College Hospital, London.
MIST, which was conducted in the United Kingdom, is the first prospective, randomized, double-blinded study to evaluate the effect of PFO (patent foramen ovale) closure on migraine headaches. NMT's proprietary PFO closure technology, STARFlex®, was exclusively used in the study. A PFO is a common heart defect that is a risk factor for migraine headaches in some patients. The PFO allows venous blood, unfiltered and unmanaged by the lungs, to enter the arterial blood circulation. The unfiltered venous blood may contain elements that can trigger migraines in some patients.
The study, which screened 432 migraine with aura patients for a PFO, enrolled 147 patients into the study. A significant finding in the MIST study is that over 60% of those screened had a right to left shunt. A shunt is a heart defect, which allows blood to cross from the right to left chambers of the heart, bypassing the lungs. Of those patients, almost 40% had a moderate or large PFO, six times greater than the general population.
Dr. Wilmshurst said, "With no prior randomized, double blind study to draw from, MIST was designed and primary endpoints were selected based upon a review and analysis of several previously reported device observational and migraine drug studies. Consistent with what was reported in the observational studies, we selected a challenging primary endpoint of 40% elimination in migraine headache at six months in the treatment group. Preliminary analysis of MIST data did not satisfy that endpoint, however, we are seeing a significant treatment effect and promising trend to support PFO closure with STARFlex® as a treatment option for certain types of migraine."
As reported today, MIST results indicated an approximate 37% reduction in migraine burden (number of headaches multiplied by the length, in hours of headache) in those patients who received a STARFlex® implant and a 17% reduction in those who received the sham procedure and no implant. This represents a statistically significant treatment effect. It also was reported that this variance appears to increase over time.
Andrew Dowson added, "For the first time we can see trends in a prospective study to suggest that PFO closure may be an effective way to treat certain types of migraine. A reduction in headache burden for a patient with severe migraine may allow that individual to gain more control and lead a more fulfilling and productive life. The key now will be establishing the criteria that will help to determine which patients should be referred to the interventional cardiologist for further treatment."
Dr. Wilmshurst added, "This study significantly increases our understanding of those patients who might benefit from cardiac intervention to treat these debilitating headaches. The results, arising from an unprecedented collaboration between cardiac and headache doctors, are a precursor to what we believe could be an exciting development in migraine treatment."
John E. Ahern, President and Chief Executive Officer of NMT, said, "Although we were disappointed that MIST did not satisfy its endpoints, the study was designed to help demonstrate clinical relevancy and not to obtain a specific regulatory approval. The study has provided us with significant data that we intend to incorporate into our MIST II and MIST III studies."
Conference Call Reminder
John E. Ahern, President and Chief Executive Officer, Richard E. Davis, Vice President and Chief Financial Officer, and Doctors Wilmshurst and Dowson, will conduct a conference call at 11:30 a.m. ET today to review the results of the MIST study. The conference call will be broadcast live over the Internet. Individuals who are interested in listening to the webcast should log on to the "Investor Relations" section of NMT Medical's website at http://www.nmtmedical.com. The conference call also may be accessed by dialing (866) 323-7221 or (706) 643-0228 (Conference ID: 5064691). For interested individuals unable to join the live conference call, a replay will be available via webcast on the Company's website.
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