GenStar Therapeutics Corp. entered an agreement with Johnson & Johnson unit Centocor Inc. to use GenStar's gene delivery vectors in preclinical studies, part of a busy day for Centocor, as Applied Molecular Evolution Inc. said it signed a deal to optimize the function of a Centocor antibody.

For San Diego-based GenStar, a certain amount of pride can be derived from attaching itself to Centocor.

"We are pleased that a leading biotechnology company such as Centocor chose us for this collaborative effort," said Robert Sobol, GenStar's CEO.

Although limited in what he could say about the deal, as well as being unable to release its financial terms, Sobol said GenStar's Max Ad technology, or a "gutted adenoviral vector," has advantages over other vector technologies.

"All the adenoviral genes have been removed," he said. "This allows us to administer the maximum amount of DNA that can be put in the vector. It has a much larger capacity than other adenoviral vectors and most other vector systems that are used currently."

Beyond the sizable payload of DNA, the technology also provides longevity, he said.

"The absence of the adenoviral gene expression permits sustaining therapeutic gene expression," Sobol told BioWorld Today. "The immune system does not destroy the infected cell by recognizing the adenoviral genes as foreign. We can get expression that goes for several months or nearly a year, compared to several weeks from more conventional adenoviral vectors."

GenStar's pipeline includes a Max Ad vector for Factor VIII, designed to treat hemophilia A. The company is expecting to complete Phase I trials by the end of the year or early in 2003. Its program for prostate cancer uses a "Dual Ad system," Sobol said, in which one of the viruses is a Max Ad virus and the other is a more conventional adenoviral vector. The viruses complement each other, resulting in viral replication and propagation in tumor tissues leading to tumor cell destruction. GenStar is aiming for Phase I prostate cancer trials to begin in late 2002 or early 2003.

GenStar's HIV vaccine program is "generating encouraging results" in preclinical work, Sobol said.

Adenoviral vector technology created significant buzz when the theory was first hatched. Time has slipped by since then, without breakthrough results. But that is to be expected, Sobol said.

"There was an initial period of great optimism, but it took time to realize there had to be time to find targets and to develop the technical improvements needed for successful clinical applications," he said. "The field is moving in that direction."

For Applied Molecular Evolution, of San Diego, its role with Centocor revolves around antibodies. Applied Molecular will use its AMEsystem technology to optimize the function of an undisclosed Centocor-provided antibody. Centocor will have all responsibilities for future development and commercialization of the antibody as a human therapeutic.

Applied Molecular receives an up-front payment through the deal, and potential milestones and royalties on sales of any resulting products. Further financial details were not disclosed.

SG Cowen Securities Corp. said in a research note: "[Applied Molecular's technology] is continuing to emerge as a competitive MAb optimization and humanization platform. [The Centocor] agreement meets the company's guidance for entering into two optimization agreements in 2002." Cowen said it anticipates Applied Molecular will enter additional agreements this year.

Applied Molecular's stock (NASDAQ:AMEV) rose 15 cents Wednesday to close at $6.85. GenStar's stock (AMEX:GNT) rose 5 cents to end the day at 83 cents.