Medical Device Daily Associate Managing Editor

NMT Medical (Boston), a developer of minimally invasive systems for the treatment of cardiac sources of migraine headaches, stroke and other potential brain attacks, on Friday reported initiating patient enrollment in its Migraine Intervention with Starflex Technology (MIST) clinical study in Europe.

The study is designed to evaluate the effectiveness of the company's Starflex implant technology in the treatment of certain migraine headaches, a potentially lucrative new application for the technology originally designed for the treatment of recurrent stroke and transient ischemic attack.

In a conference call, NMT said that the new indication could have a more immediate impact on the company's growth than that of its initial stroke focus.

“The initiation of our MIST trial is a landmark event for NMT as we expand our PFO [patent foramen ovale] closure focus beyond stroke to other brain attacks,“ said John Ahern, NMT's president and CEO. “We believe that PFO closure for migraine represents a substantial and more immediate revenue growth opportunity for NMT as compared to stroke.“

Ahern added that the patient recruitment for MIST has progressed more quickly than originally anticipated, “so we now expect to complete enrollment in the third quarter of 2005, one quarter ahead of our initial year-end target.“

As disclosed last year (Medical Device Daily, Nov. 9, 2004), NMT received approval in the UK for the MIST study. MIST is a double-blinded study randomizing migraine patients with a PFO to either PFO closure with the Starflex implant or a control arm. Study patients will be followed for six months.

MIST is the first prospective, randomized, controlled study to evaluate the potential relationship between PFO, a common structural heart defect, and certain migraine headaches, NMT said. A PFO allows venous blood, unfiltered by the lungs, to shunt, or flow, into the arterial circulation of the brain. This unfiltered venous blood may contain elements that possibly trigger migraine headaches or other brain attacks in some patients.

The Starflex septal repair technology closes the PFO in a minimally invasive procedure. The PFO closure procedure using Starflex takes about 30 minutes to perform in a cardiac catheterization lab. Patients can return to normal activity soon after the procedure. To date, the company said, more than 15,000 PFOs have been closed globally with NMT's implant technology.

MIST is a multi-center study involving approximately 15 centers, with an expected enrollment of fewer than 200 patients. The study was designed by a scientific advisory board comprised of some of the top European and North American migraine specialists and cardiologists, the company said.

The MIST study's patient recruitment process is supported by the Migraine Action Association (MAA), a migraine headache advocacy group representing more than 14,000 members in the UK.

Ahern said the company has been greatly encouraged by the overwhelming response it received from migraine sufferers, dissatisfied with their current level of treatment who indicated their wish to enroll in the trial.

“We knew going into the MIST study that migraine patients would have interest in learning more about the study, [and] the potential PFO/migraine connection,“ he said. “Once we announced the study, however, both the company and the Migraine Action Association were surprised at the higher than expected level of migraine sufferers who contacted the [MAA] directly or logged on to the web site and inquired about the eligibility to enter the study.“

Ahern noted that a study published in the December 2004 issue of the British Journal of Medicine shows that migraine patients have twice the risk of stroke of the general population. He also pointed out that migraine sufferers have two to three times the suicide risk of the general population “So unlike what some people may think, migraine disease is not just a headache.“

Underscoring the importance of a successful trial, Ahearn said, “If the MIST trial is successful in demonstrating that PFO closure with Starflex shuts down a process that may be triggering or contributing to certain migraine attacks, it would represent a potential breakthrough treatment for patients currently not responding to other therapies. It also would provide NMT with a very promising opportunity that we could aggressively pursue in the near-term. Based on our current implant selling price and the 5% initial target population, which represents 3.8 million migraine sufferers [1.5 million in the U.S. alone], we estimate this opportunity to be in excess of $15 billion.“

“NMT's MIST study is designed to determine whether PFO closure offers these patients an alternative to lifelong medical therapy,“ said Andrew Dowson, MD, director of the Kings Headache Service of Kings College Hospital (London), and co-primary investigator for MIST. Ideally, he said the study would establish that PFO closure not only helps reduce the frequency and severity of migraine attacks, but has the potential to eliminate some migraines completely for some people. “The headache specialist community is watching the MIST study with great interest,“ Dowson said.

“We believe that our initial target patient population for PFO closure with our technology would be 5% of all migraine sufferers,“ said Ahern. This is based on statistics from the World Health Organization (Geneva, Switzerland) and the American Council for Headache Evaluation (Mt. Royal, New Jersey), which indicates the prevalence of migraines in the U.S., Europe and Japan is about 10% of the general population. Also, published medical research indicates that approximately 20% of migraine sufferers have migraine with aura, often referred to as the classic migraine, and that up to 50% of those suffering from migraine with aura are unresponsive to current medications.“

The company outlined key objectives for its migraine program: Complete MIST patient enrollment in 3Q05; strengthen its European sales organization to pursue migraine opportunity in second half of 2005; meet with the FDA in 1Q05 regarding design of a U.S. migraine study; and commence U.S. migraine study in the second half of 2005.

NMT also disclosed that it expects its results for the full year to be in line with the guidance it provided in its third-quarter news release. The company said on Nov. 10, 2004, that it expected total revenues of greater than $21 million for 2004, a decrease of about 6% compared to 2003, and worldwide cardiac septal repair implant sales for the full year 2004 to decrease by roughly 20% to 25% compared to 2003. It currently expects to end 2004 with approximately $35 million in cash, cash equivalents and marketable securities, ahead of its previous guidance of $32 million.

In another PFO-related piece of news, privately held Velocimed (Minneapolis) reported that is has received the CE mark for its Premere PFO closure system,

Premere is designed, the company said, to “redefine“ PFO closure. Consisting of two flexible, low-profile, nitinol anchors connected via an adjustable length polyester tether, the system is designed to adapt to the patient's individual anatomy, maximizing closure success while minimizing procedural complications.

This first-of-its-kind design is intended to enable greater placement control during deployment. The anchors, Velocimed said, “are designed to conform seamlessly to the septal wall to 'hold the door shut,' promoting rapid endothelialization and closure of the PFO.“ The system will be available in 15 mm, 20 mm and 25 mm sizes.

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