FDA Approves Prezista for HIV Salvage Therapy

ROCKVILLE, Md., June 27 - The FDA has given accelerated approval to a novel protease inhibitor for salvage treatment of patients with HIV.

Prezista (darunavir) was approved only in adults whose HIV infection is not responding to other drugs. It was not indicated as first-line therapy nor was it approved for children.

The medication, developed by Tibotec, Inc., of Raritan, N.J., is to be co-administered with Norvir (ritonavir), a protease inhibitor that is often used to boost the effect of other protease inhibitors by slowing their breakdown in the body. It is a potent inhibitor of hepatic microsomal enzyme CYP (450) 3A4. It is also meant to be used as part of a highly active anti-retroviral therapy (HAART) drug cocktail.

Commenting on the approval, Andrew C. von Eschenbach, M.D., the acting Commissioner of Food and Drugs, said it "offers new hope to HIV patients who too often urgently need new therapies in order to maintain their health."

Like all other HIV medications, he added in a statement, "this drug is not a cure, but when combined with other standard therapies, it presents one more major step in our effort to help patients combat the effects of the disease."

The approval was based on two randomized controlled trials that compared the safety and effectiveness of a Prezista/Norvir combination with other Norvir-boosted protease inhibitor combinations. In both, patients on a Prezista/Norvir combination saw their HIV viral load reduced more than patients on other Norvir-boosted protease inhibitor combinations.

Overall, 70% of treatment-experienced patients achieved a virologic response with Prezista/Norvir compared with 21% in control groups at week 24 of the studies, the FDA reported.

Prezista is to be taken as two 300-mg tablets twice daily, along with 100 mg of Norvir twice a day; it should be taken with food to enhance gastric absorption and minimize gastrointestinal side effects of Norvir.

As a condition of approval, Tibotec is required to conduct post-marketing trials "to verify and describe the clinical benefits of Prezista," the FDA said. The company will also study the drug in pediatric populations, examine some known drug-drug interactions, and conduct dosing studies in patients with varying degrees of liver impairment.

The most common side effects reported by patients taking Prezista/Norvir in clinical trials were diarrhea, nausea, headache, inflammation of the nose and throat, and skin rashes, which were mostly mild to moderate.

The drug has a range of drug-drug interactions-from some anti-fungals to St. John's Wort-and patients and physicians were advised to take care when using or prescribing Prezista in order to avoid complications.

Other protease inhibitors have been associated with large increases in lipid levels, but it is not yet known what effect Prezista will have on lipids.