Merck & Co.’s Isentress was approved by FDA for use with other antiretroviral drugs for the treatment of HIV-1 infection in children and adolescents ages 2–18. It was first approved for use in adult patients in October 2007, under FDA's accelerated approval program.
The drug is part of a class of medications called HIV integrase strand transfer inhibitors, which slows the spread of HIV in the body. Isentress is a pill that can be taken twice daily, with or without food. The pill is also available in a chewable form. Because the two tablet formulations are not interchangeable, the chewable form is only approved for use in children ages 2–11.
A single, multicenter clinical trial of 96 children and adolescents ages 2–18 years with HIV-1 infection evaluated the safety and effectiveness of Isentress. These patients previously received treatment for HIV-1 infection. After 24 weeks of treatment with Isentress, 53% had an undetectable amount of HIV in their blood.
The most commonly reported severe, treatment-related side effects in patients taking Isentress include insomnia and headache. The frequency of these side effects is similar for children and adults.
"Many young children and adolescents are living with HIV, and this approval provides an important additional option for their treatment," says Edward Cox, M.D., director, office of antimicrobial products in the FDA's Center for Drug Evaluation and Research.
Since initial accelerated approval in the U.S., Merck has been able to secure full approval for the 400 mg tablets in combination with other antiretroviral agents for the treatment of HIV-1 infection in treatment-experienced adult patients in January 2009. Similarly in Europe, Isentress started out under conditional approval but now has full approval in the same indication as in the U.S.
Merck reported that Isentress pulled in $343 million during this year’s third quarter, a 23% increase from the same period last year, which saw sales of $278 million. The company said growth was driven by demand in both the U.S. and Europe.