Studies: Newer HIV Drugs More Tolerable for Many

Patients on newer HIV drugs did well and had fewer side effects that stopped treatment, according to several studies presented Sunday in Washington at the 48th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy. The company-funded studies could support extending first-line approval to HIV drugs now used for treatment-experienced patients failing therapy.

In a Merck & Co. study of 563 treatment-naïve patients, half the participants took Merck's integrase inhibitor Isentress plus Truvada, and the other half took Sustiva plus Truvada. After 48 weeks, 86 percent of Isentress patients had achieved an undetectable viral load, compared with 82 percent of Sustiva patients. Serious side effects were reported for 44 percent of Isentress patients, leading eight patients to stop the treatment. In comparison, 77 percent of Sustiva patients had serious side effects, leading 18 to discontinue the regimen.

A new Pfizer report analyzed older data from a 48-week study of 417 patients who took either Selzentry plus Combivir or Sustiva plus Combivir. In both groups, 68 percent achieved an undetectable viral load. Just 4.2 percent of Selzentry patients stopped taking it due to side effects, compared with 14.2 percent of Sustiva patients. The analysis included only patients screened to ensure that Selzentry would work on their virus, a strain found in 50-80 percent of patients. The drug blocks HIV strains that infect cells through the CCR5 co-receptor.

A four-year Schering-Plough Corp. study involved 205 treatment-experienced patients taking the firm's CCR5 entry inhibitor vicriviroc. Patients had sustained viral suppression and improved CD4 cell counts, and less than 5 percent developed infections. However, 14 patients developed AIDS complications and 13 got various cancers.

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Excerpted from:
Associated Press
10.26.2008; Linda A. Johnson