FDA and HIV: A warning and a rejection this week

FDA warns that hepatitis C drug Victrelis may reduce efficacy of Norvir-boosted protease inhibitors and rules against NeurogesX patch for HIV-related pain

Jeffrey Bouley
The end  the first full week in February saw the U.S. Food and Drug Administration (FDA) make a pair of proclamations related to HIV but not with direct regard to drugs that combat HIV/AIDS. In a public statement, FDA warned  that the hepatitis C drug Victrelis has been found to reduce theefficacy of several Norvir-boosted protease inhibitors, and around the same time, an FDA panel of outside experts ruled against using a pain-relief product derived from chili peppers to treat a kind of pain that many HIV patients suffer in their extremities, referred to as HIV associated peripheral neuropathy (HIV-PN).

With regard to the latter, in a 12-0 vote, the FDA advisory committeefound that clinical data did not show substantial evidence thatNeurogesX Inc.'s Qutenza capsaicin patch was effective at treatingneuropathic pain among people infected with the virus that causes AIDS.
The panel also voted 11-0, with one abstention, that Qutenza's risk-benefit profile was not acceptable for use in HIV patients.
 
"We will continue to work closely with the FDA to address the Advisory Committee's comments as the Agency finalizes its review of our sNDA," said Ronald Martell, CEO and president of NeurogesX. "We remain confident that Qutenza has the potential to address significant, unmet medical needs and toimprove the quality of life for patients with HIV-PN. We would like tothank the FDA and the advisory committee members for their careful and thoughtful deliberation on this matter." 

With regard to Merck & Co.'s Victrelis, the FDA noted that the drug reduces the blood concentrations of Norvir-boosted Reyataz, Prezista, and Kaletra.
 
The FDA didn't tell patients to stop taking Victrelis ortheir antiretrovirals if they have been prescribed; however, patientsshould be closely monitored for antiretroviral treatment failure orhepatitis C treatment failure.
 
The FDA also encouraged patients to report any side effects theyexperience while taking Victrelis or their HIV protease inhibitors tothe FDA's MedWatch program.
Victrelis (boceprevir) was approved by the FDA in May of last year for thetreatment of hepatitis C, in combination with peginterferon-alfa(PegIntron, Pegasys) and ribavirin (Rebetol, Copegus) (see related AIDS Beacon news). It was not approved at the time for people with both HIV andhepatitis C, due to lack of information on efficacy in people who areco-infected.
 
Nonetheless, the FDA writes, "some people with HIV and advanced hepatitis C infectionhave been prescribed Victrelis 'off-label.' Although the drug has notbeen approved for people with HIV, physicians may legally prescribe itif they think it is appropriate."
 
Victrelis has also been given to people with HIV as part of severalclinical trials that must be conducted before the drug can be approvedfor people with both HIV and hepatitis C. One of the trials is a druginteraction trial; results from this study prompted the warning from the FDA.
 
Results showed that when taken together, Victrelis reduced the minimum blood concentrations of Kaletra (lopinavir/ritonavir) and Norvir (ritonavir)-boosted Reyataz (atazanavir) and Prezista (darunavir) by 40 percent to 60 percent, according to the FDA. The agency also noted that lower concentrations of the drugs in the bloodstream can reduce their efficacy, potentially leading to treatment failure.
 
In addition, Kaletra and Norvir-boosted Prezista reportedly reduced the bloodconcentration of Victrelis by 45 percent and 32 percent, respectively.Norvir-boosted Reyataz had no effect on the concentration of Victrelisin the blood.
 

Jeffrey Bouley

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