Boston Life Sciences Inc. still sees a new drug application in the future for Altropane, its radioimaging agent for the diagnosis of Parkinson's disease, but first it must conduct an additional Phase III trial to satisfy the FDA.

"We recognize that our strategy will delay the filing of the NDA, which we previously indicated would occur by the end of the first half of 2003," Robert Rosenthal, the company's president and CEO, said in a release. "However, we have concluded that this course of action represents the best long-term strategy to fully maximize the market potential for Altropane and is, consequently, in the best interests of movement disorder patients and our shareholders."

The news sent Boston Life Sciences' stock (NASDAQ:BLSI) into a 24.1 percent slide Tuesday, as it dropped 57 cents and closed at $1.80.

The Boston-based business said its steps are in line with FDA advice. The company outlined plans to pursue a special protocol assessment (SPA) related to the compound, saying that it intends to file the SPA with the FDA shortly in connection with the supplementary study in essential tremor patients prior to NDA submission. Boston Life Sciences said the agency recommended the course during recent discussions.

The trial is designed to distinguish benign essential tremor from Parkinsonian tremors.

According to FDA-published guidance, a SPA filing provides for a 45-day review of a Phase III trial protocol. The review forms the basis of an agreement with the agency regarding the steps needed for eventual approval of a company's NDA filing.

Rosenthal added that the SPA and additional Phase III trial would "place us in a stronger position to secure approval."

Altropane also is being studied in a Phase IIb trial as an imaging agent for attention deficit hyperactivity disorder. The publicly traded company, which raised $10 million through a private placement earlier this year, also has plans to begin clinical studies of the nerve growth factor Inosine for stroke late this year or early next year. (See BioWorld Today, March 14, 2003.)

Deeper in its pipeline, another imaging agent called Fluoratec is in preclinical development for diagnosing Parkinson's disease and attention deficit hyperactivity disorder. Other preclinical products include Troponin I, an anti-angiogenesis factor for solid tumors, and a nerve growth factor called AF-1 for acute and chronic central nervous system disorders.