HIV Digest	HIV Digest Archive

The Houston-based biotechnology firm Tanox Inc. reported encouraging results from an ongoing Phase II safety and efficacy study of its intravenous HIV entry inhibitor drug TXN-355.

Designed to block entry into human cells by both X4 and R5 classes of HIV, TXN-355 lowered HIV levels in blood better than a placebo in 82 patients in the trial, with only mild adverse drug reactions reported so far, said Tanox. Patients in both control and TXN-355 groups also received a standard AIDS drug cocktail.

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TXN-355 is created from the natural infection-fighting monoclonal antibodies of mice; these are genetically engineered to lose their mouse qualities and behave like human antibodies. R5 and X4 viruses use different portals to enter cells; Tanox said the dual-class blocking TXN-355 represents "a major advantage" over drugs that block HIV from infecting cells through one portal only.

Granted fast-track status by the Food and Drug Administration, TXN-355 could be used for a broad class of HIV patients, including those with HIV resistant to multiple drugs. Tanox plans to begin a final Phase III study next year, hoping that the drug could be on the market as early as 2009.

Editor's Note: from the Wall Street Journal