FDA approves new protease inhibitor

The Food and Drug Administration on Tuesday approved a new protease inhibitor developed by GlaxoSmithKline and Vertex Pharmaceuticals. The drug, originally known as 908 but now dubbed Lexiva, is a pro-drug version of the protease inhibitor Agenerase. Pro-drugs are inactive substances that are converted into an effective medication by the body's enzymes or other metabolic processes, which can avoid some of the toxic side effects of medications that do not require enzyme activation. Lexiva is taken as two tablets either once or twice per day, depending on dosage strength. Patients who have taken other antiretrovirals should take Lexiva twice per day, company officials say. Vertex announced in July that Phase III clinical trial data showed Lexiva was slightly less effective in suppressing HIV viral loads than Abbott Laboratories' protease inhibitor Kaletra in a first-line drug regimen but that Lexiva was as potent as Kaletra for HIV patients already treated with antiretroviral drugs. Lexiva is approved for use as part of a multidrug cocktail for HIV-positive adults. The drug will be available in 700-milligram tablets.