Merck's ISENTRESS Approved by FDA to Treat HIV-1 in Newborns

Merck Pharmaceuticals’ integrase inhibitor raltegravir (ISENTRESS) was recently approved by the US Food and Drug Administration (FDA) to be used in combination with other available antiretroviral treatments (ART) to treat certain newborns with HIV-1.

ISENTRESS is designated as part of a combination therapy in neonates, or newborn patients between birth and 4 weeks of age who weigh at least 2 kg, according to a recent press release. Its approval was backed by safety data yielded by an open-label, multicenter clinical study called IMPAACT P1110, which evaluated the pharmacokinetics of oral ISENTRESS in 42 full-term HIV-1 exposed newborns. All of the newborns incorporated in the study were deemed to be at high risk of acquiring the infection from their mothers.

IMPAACT P1110 was a 2-cohort trial. In the first cohort, newborns received 2 single doses of ISENTRESS for oral suspension — one within 48 hours of birth, and the other between 7 and 10 days of age. In the second cohort, newborns received ISENTRESS each day for 6 weeks at doses set by patient weight.

All of the patients also received a standard ART regimen for the prevention of HIV transmission from the mothers. By the study’s close, all patients tested negative for the virus, and investigators found the drug’s safety profile to be comparable to that observed in adult patients.

ISENTRESS was first approved as an adult HIV-1 infection therapy in 2007, the first such integrase inhibitor for the disease; it is regulated in 112 countries as a combination therapy for HIV-1 infection in adult and adolescent patients, according to Merck.

The drug functions by “inhibiting the insertion of HIV-1 DNA into human DNA by the integrase enzyme,” according to the press release. ISENTRESS has shown clinically rapid antiviral activity, limiting the ability of the virus to replicate and infect new cells in patients.

Eliav Barr, MD, senior vice president of Infectious Diseases and Vaccines Global Clinical Development at Merck Research Laboratories, said few ART agents are approved for the newborn population with HIV-1 infections, mainly due to limited clinical research.

“With this FDA approval, ISENTRESS becomes the only integrase inhibitor approved in the United States for the treatment of HIV-1, in combination with other antiretroviral agents, for neonates weighing at least 2 kg,” Dr. Barr said. “This achievement underscores Merck's unwavering commitment to the development of treatment options for HIV-1."