By Mary Welch

With a product candidate based on the Medisorb drug delivery system developed by Alkermes Inc., the Janssen Research Foundation said it will start Phase III trials of an intramuscular injectable, sustained-release formulation of the antipsychotic drug Risperdal (risperidone).

Jay Silverman, senior analyst with BancBoston Robertson Stephens Inc., in New York, called the news ¿an important milestone for Alkermes,¿ since Janssen¿s testing represents the first Phase III trials for the Medisorb technology.

Jim Frates, vice president and chief financial officer at Cambridge, Mass.-based Alkermes, said the company is compensated for certain achieved milestones, but declined to divulge them or disclose any details about the planned Phase III.

In 1996, Alkermes signed a $20 million deal with Janssen Pharmaceutica, of Beerse, Belgium, that paired Medisorb with an unidentified drug. With the onset of Phase III trials, this is the first time the companies revealed that Risperdal was the drug involved. The Janssen Research Foundation is a division of Janssen Pharmaceutica, which is a subsidiary of Johnson & Johnson (J&J), of New Brunswick, N.J.

Alkermes has completed scale-up and Phase III manufacturing activities at the expected commercial site in Wilmington, Ohio, near Cincinnati.

Silverman said Risperdal is J&J¿s ¿second largest drug. It¿s over $1 billion in sales. So, J&J didn¿t take this lightly. They were very thorough, and did large-scale Phase II studies. They wanted to be certain before they announced which drug was involved and moved forward.¿

Risperdal, the first new front-line option for treating schizophrenia and other psychotic disorders in 20 years, helps manage schizophrenia¿s ¿positive¿ symptoms, such as visual and auditory hallucinations, delusions and thought disturbances, as well as the ¿negative¿ symptoms, such as social withdrawal, apathy, lack of motivation and inability to experience pleasure, according to the National Alliance for the Mentally Ill, in Arlington, Va.

Next Milestone: NDA For Nutropin Depot

Risperdal is usually taken twice a day, although, because of its long half-life, daily dosing may occur. The recommended dose is usually reached within three to four weeks, with improvement noticed more quickly in some patients. Side effects are described as minor.

An antagonist that seems to block serotonin and dopamine in the brain, Risperdal has an advantage over conventional antipsychotics, which primarily seem to affect only dopamine, the alliance noted.

The Medisorb drug delivery system provides injectable, sustained-release formulations, made from traditional small molecules and peptides, that last from days to months. The system is composed of biodegradable microspheres containing the desired drug incorporated into a polymer matrix.

Silverman said the next expected milestone for Alkermes is the filing of a new drug application ¿ the company¿s first ¿ for Nutropin Depot, using the ProLease system. Nutropin Depot is a sustained-release formulation of somatropin (recombinant human growth hormone) that is used for treating children with growth hormone deficiency. The ProLease injectable, sustained-release drug delivery system encapsulates the compound in biodegradable microspheres. In that project, Alkermes is partnered with South San Francisco-based Genentech Inc. (See BioWorld Today, Oct. 23, 1998, p.1.)

Alkermes¿ stock (NASDAQ:ALKS) closed Thursday at $28.250, down $0.750. n