Data presented at a retroviruses conference earlier this year suggest a potential association between fosamprenavir therapy and myocardial infarction in HIV-infected adults, GlaxoSmithKline said in a letter (PDF) circulated today by FDA.

As a result, the company said it updated the labeling for fosamprenavir, or Lexiva, to note that myocardial infarction and hypercholesterolemia have occurred in patients who received the protease inhibitor since its approval by FDA.

The agency first approved the marketing of fosamprenavir in 2003.

FDA-approved labeling for the drug has always stated that a cholesterol test should be performed before a patient starts therapy and then periodically thereafter. Lipid disorders should be managed as is clinically appropriate.

The data to which GlaxoSmithKline referred was presented at the 16th Conference on Retroviruses and Infections in February. According to the abstract, the risk of MI was increased by patients' cumulative exposure to fosamprenavir, amprenavir, or lopinavir.

FDA-approved labeling for amprenavir, which GlaxoSmithKline does not apparently actively promote in the United States, already states that hypercholesterolemia has developed during therapy.

The labeling for lopinavir, from Abbott Laboratories, states that myocardial infarctions have occurred during therapy and total cholesterol levels have increased greatly in some patients.