DUBLIN, Ireland ¿ Bristol-Myers Squibb Co. withdrew from its alliance with Neurosearch A/S to develop the anti-Parkinson¿s drug brasofensine.

Neurosearch, of Glostrup, Denmark, will continue development of the compound, a dopamine reuptake inhibitor, on its own. Bristol-Myers¿ departure already has sparked interest from other quarters, however.

¿We have been contacted by three companies who are interested,¿ company president and CEO Jorgen Buus Lassen told BioWorld International. Neurosearch will enter discussions with these firms after its next meeting with the FDA, in September, he said.

The collaboration with Bristol-Myers, which began in 1995, had reached Phase II trials when it ran into complications. Clinical studies indicated the conversion of brasofensine into a different isomeric form, characterized by an altered orientation of a methoxy group. The conversion reaction is particularly favored in low pH environments, and occurs to a greater extent in humans compared with small animals.

The two forms show no differences in biological action, Lassen said, although the newly observed isomeric form has a longer circulatory half life than the clinically preferred form of the compound, which is more stable in solid formulations.

Neurosearch, therefore, decided to conduct extra metabolic and toxicological studies, which prompted Bristol-Myers¿ withdrawal from the program. That work already is under way, Lassen said. Pending successful completion, the FDA has imposed a dosage restriction on the administration of brasofensine in clinical trials conducted in the U.S. In Europe, health authorities have limited clinical trials to a treatment period of four weeks.

Neurosearch has regained all scientific and commercial rights to the product, including the results of studies Bristol-Myers conducted during the period of the agreement. The company also has retained all of the up-front payments and approximately DKK 70 million (US$9.6 million) in milestone payments it garnered from the alliance.

However, the loss of further milestone payments, combined with the extra costs associated with pursuing the program on a solo basis, will result in an unforeseen DKK 15 million in expenses in the current fiscal year. The company now expects to post total losses of DKK 85 million this year.