LONDON - Cantab Pharmaceuticals plc reported results from Phase I trials of its herpes simplex virus (HSV) vaccine for treatment and prevention of genital herpes, under development with Glaxo Wellcome plc. The studies showed the vaccine is safe and immunogenic at three lower dose levels.

Trials of mid-to-high doses of the DISC HSV vaccine should be completed by the end of 1998, with Phase II multi-center, placebo-controlled studies due to begin in 1999.

The findings, presented at the 8th International Congress of Infectious Diseases, in Boston, revealed that the most dramatic responses to the vaccine occurred in previously uninfected volunteers, with six out of six subjects showing an HSV-specific response at the highest dose.

In subjects that were previously infected with HSV, immunization with DISC HSV resulted in slight increases in existing immune responses in only some of the subjects. The company is hoping for a more convincing response at higher doses. Immunogenicity was evaluated by measuring a number of cell-mediated immune responses.

Virus In Vaccine Cannot Replicate

John Roberts, medical director of Cantab, which is based in Cambridge, U.K., said the studies “help validate the mechanism of action of the DISC HSV vaccine. They also provide valuable support for the DISC [disabled infectious single cycle] virus platform as a whole. The unique characteristics of our genetically engineered viruses hold the potential for multiple product development applications.“

Cantab's viruses are disabled, so they are able to infect cells and raise an immune response but are unable to undergo subsequent replication.

Cantab also reported results for the first quarter ended March 31, 1998, showing losses of £1.2 million, compared with a profit of £3.4 million in the same period of 1997. Revenues fell to £1.1 million from £5.4 million. Most of the 1997 profit was due to payment of a license fee of £5 million from London-based Glaxo Wellcome for DISC HSV.

Operating expenses increased to £3.1 million from £2.5 million in 1997, and the closing cash position at March 31, 1998, was £39.7 million, compared with £46.9 million the year before.

The company also disclosed plans for a five-for-two share split. A spokesman said most of Cantab's shares are “tied up with venture capitalists who have been unwilling to sell. As a result there are very few shares in public hands.“

The company expects that increasing the number of shares venture capitalists hold will have a psychological effect, encouraging them to sell and promoting wider share ownership. *