By Mary Welch

Synaptic Pharmaceutical Corp. and Eli Lilly and Co. said their serotonin receptor agonist to treat migraine headaches is aimed for Phase III clinical trials, with Lilly assembling a team to take control of the studies and of marketing of the drug.

Kathleen Mullinex, chairman, president and CEO of Paramus, N.J.-based Synaptic said no determination had been made of a start date for the trials, or their endpoints.

"All I can say is that it will be a global trial and [the drug] will be an oral formulation," Mullenix said.

The compound, an agonist of the 5-HT1F (or serotonin) receptor, is part of a collaboration with Indianapolis-based Lilly that began in 1991 and was expanded in 1996. (See BioWorld Today, Nov. 5, 1996, p. 1.)

Three Phase II trials — two in the U.S., one in Europe — showed the drug's efficacy without cardiovascular side effects associated with migraine products already on the market, Mullenix said.

James Kappel, manager of financial communications at Lilly, said a "detailed registration plan is being developed along with a definitive timetable" for the Phase III studies.

Serotonin is a neurotransmitter that has been implicated in a variety of central nervous system disorders, such as depression, anxiety, migraine headaches, sexual dysfunctions, gastrointestinal movement and sleep disorders. Synaptic discovered and patented the human 5-HT1F (5-Hydroxytryptamine) receptor.

Migraines are periodic, throbbing headaches often accompanied by nausea and vomiting. As much as 10 percent of the general population may suffer from migraines, and the market for therapies is an estimated $1.2 billion, which could grow to $3 billion by 2000, Synaptic said.

The compound to enter Phase III trials is designed to boost levels of serotonin to counter the inflammatory cascade that may be responsible for the headaches. Since its binding is specific, rather than to multiple receptor subtypes, fewer effects are noted, if any.

Christian Fibiger, Lilly's vice president of the division for neruroscience discovery research and clinical investigation, said data suggest the selective 5-HT1F agonists "represent a new class of compound that will treat migraine pain via neuronal mechanisms."

Synaptic has three other collaborations, with Warner-Lambert Co., of Morris Plains, N.J.; Merck & Co., of Whitehouse Station, N.J.; and Grunenthal GmbH, of Aachen, Germany.

Synaptic's stock (NASDAQ:SNAP) closed Thursday at $12.750, up $1.662. *