The US Food and Drug Administration has granted accelerated approval for Isentress (raltegravir) tablets to be used along with other antiretroviral agents for HIV-1 infection for adult patients who have evidence of viral replication and who have developed resistance to multiple antiretroviral agents.
Further trials will be needed before considering its approval for new HIV patients and children.
The approval is based on analyses of plasma HIV-1 RNA levels up through 24 weeks in two Isentress trials.
New way to fight HIV
Isentress is the first integrase inhibitor to be approved. The drug hinders the insertion of HIV DNA into human DNA by the integrase enzyme. By hindering integrase from functioning it undermines the virus’ ability to reproduce and contaminate other cells. Although there are other drugs that inhibit other enzymes vital for the HIV replication process, Isentress is the only approved one that inhibits the integrase enzyme.
After analyzing clinical trials in which Isentress was given in combination with OBT (optimized background therapy) in treatment-experienced patients, the FDA accepted that the drug provided substantial reductions in HIV RNA viral load and caused CD4 cell counts to rise.
Joseph J. Eron Jr., M.D., professor of medicine, Division of Infectious Diseases, UNC Chapel Hill School of Medicine, said “The development of ISENTRESS is a significant milestone in the history of HIV/AIDS therapy because we now have a drug that’s potent against another key enzyme essential for viral replication. It’s important for physicians to know that ISENTRESS should always be used in combination with other active agents.”
Isentress Safety Information
Isentress does not prevent the passing of HIV from one person to another, neither does it cure HIV or AIDS. Doctors should be aware that immune reconstitution syndrome can occur in patients who are treated with antiretroviral therapy; this may require further evaluation and treatment.
The most common adverse experiences were diarrhea, nausea, headache and fever. Some patients who received Isentress experienced raised creatine kinase levels; others experienced myopathy and rhabdomyolysis (it is unclear whether myopathy and rhabdomyolysis were linked to Isentress).
Isentress
It is a single 400 mg tablet which should be taken twice a day, with or without food – it does not need boosting with ritonavir. The WAC (wholesale acquisition cost) will be $27 per day – Merck; the makers comment that this price is similar to that of several ritonavir-boosted protease inhibitors.
To assist US patients who cannot afford Isentress treatment, the SUPPORT program is available. Merck also participates in the Partnership for Prescription Assistance program. Isentress will be on pharmacy shelves within the next two weeks.
Some HIV/AIDS facts – 2006 (World Health Organization)
— World – 39.5 million are living with AIDS/HIV
— New infections – 4.3 million (65% in sub-Saharan Africa)
— Infection rates in Central Asia and Eastern Europe have gone up by over 50% since 2004
— Deaths from AIDS – 2.9 million (of which 380,00 were under 15 years of age)
Written by: Christian Nordqvist