June 23, 2006 (AIDSmeds)—The U.S. Food and Drug Administration (FDA) announced on June 23 that it has approved Prezista™ (darunavir), a new drug for adults whose infection with HIV is no longer responding to treatment with other anti-HIV drugs. Prezista, a new protease inhibitor developed and manufactured by Tibotec, Inc., is approved to be taken with a low-dose of Norvir® (ritonavir) and other active anti-HIV agents.

“This approval offers new hope to HIV patients who too often urgently need new therapies in order to maintain their health,” said Andrew C. von Eschenbach, MD, Acting Commissioner of Food and Drugs. “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 accelerated approval is based on evidence from two randomized, controlled studies comparing the safety and effectiveness of a Prezista/Norvir combination with other Norvir-boosted protease inhibitor combinations. Patients in both arms of these trials also used other anti-HIV agents (nucleoside reverse transcriptase inhibitors) with or without Fuzeon® (enfuvirtide), a fusion inhibitor that inhibits the virus from entering the cell. In these studies, patients on a Prezista/Norvir combination experienced higher rates of reduction of their HIV viral load than patients on other Norvir-boosted protease inhibitor combinations. Seventy percent of treatment-experienced patients achieved a virologic response, improving the treatment outcome, with Prezista/Norvir in combination therapy compared to 21% in control group at week 24.

The most common side effects reported by patients on the Prezista/Norvir regimen included diarrhea, nausea, and headache. Approximately 7% of patients on this combination therapy experienced skin rashes ranging from mild to serious. Prezista is a sulfa-containing drug and should be used with caution in patients with a known sulfa allergy.

The risks and benefits of Prezista have not been established for adults who are starting HIV treatment for the first time, or for children.

As a condition of the accelerated approval, the manufacturer is required to conduct post-marketing trials to verify and describe the clinical benefits of Prezista. Other postmarketing studies that the manufacturer has committed to conduct include studies in children, studies to better define certain drug-drug interactions, and to evaluate the drug in patients with varying degrees of liver impairment to identify appropriate dosing for this patient population.

Patients are advised to take Prezista/Norvir with food, and not to use the combination therapy together with St. John’s wort or various other drugs, including certain anticonvulsants, antihistamines, sedatives, and a few of the protease inhibitors.