The FDA has approved Isentress HD, a novel 1200-mg dose of raltegravir (Isentress) to be administered in combination with other antiretrovirals for the treatment of HIV-1, according to a press release. Isentress HD is administered in two 600-mg tablets once per day.  

The FDA approved the administration of Isentress HD in patients weighing at least 40-kg who are treatment-naïve or who achieved viral suppression from treatment with raltegravir.   “Isentress has been used as a component of treatment regimens for patients diagnosed with HIV-1 for almost a decade,” said Michael S. Saag, MD, associate dean for global health, and director of the Center for AIDS Research at the University of Alabama at Birmingham School of Medicine. “The addition of a convenient once-daily version with a comparable efficacy and safety profile at 48 weeks to the existing twice-daily version of Isentress provides physicians with a new therapeutic option for some patients with HIV-1 infection.”  

The new approval of Isentress HD was supported by positive findings from the ONCEMRK phase 3 clinical trial including treatment-naïve patients with HIV-1. Patients were treated with once daily Isentress HD 1200-mg (administered as two 600-mg tablets) or Isentress 400-mg twice per day emtricitabine + tenofovir disoproxil fumarate.  

At 48 weeks, approximately 89% of patients treated with Isentress HD 1200-mg achieved viral suppression of HIV RNA <40 copies/mL compared with 88% of patients treated with Isentress 400-mg twice per day, according to the study.  

“Because of improvements in the effectiveness of antiretroviral therapies and with appropriate access to care, HIV infection can now be managed as a chronic disease,” said Carl Schmid, deputy executive director of the AIDS Institute. “For people living with HIV, having a wide range of effective therapies is important because it provides options to fit patients’ individual needs and lifestyles.”  

Through 48 weeks, only 3% of patients in both treatment groups discontinued therapy due to adverse events. This suggests that the drugs were well-tolerated overall. Adverse reactions of all intensities reported in the clinical trial include abdominal pain, diarrhea, vomiting, and decreased appetite. Treatment-related viral mutations that resulted in drug resistance occurred in less than 1% of patients treated with Isentress HD, according to the release.  However, Merck officials note that potentially life-threatening skin reactions to the drugs have been reported, including Stevens-Johnson syndrome, hypersensitivity reaction, and toxic epidermal necrolysis. Treatment with Isentress or Isentress HD should be discontinued at the start of hypersensitivity or severe rash.  

Although Isentress and Isentress HD can achieve viral suppression, the drugs do not cure HIV or AIDS, according to the release.  

While Isentress HD was administered with emtricitabine + tenofovir disoproxil fumarate in the clinical trial, many antiretroviral and non-antiretroviral agents can be used. However, co-administration with aluminum and/or magnesium-containing antacids, calcium carbonate antacids, rifampin, tipranavir/ritonavir, etravirine, and inducers of drug metabolizing enzymes should be avoided, Merck reported.   The newly approved once daily Isentress HD will be the same cost as Isentress twice daily, which may further incentivize patients to explore the new treatment option. Isentress HD should be available for retail sale in approximately 4 weeks, according to the press release.  “ISENTRESS HD exemplifies Merck’s unwavering commitment to innovation in HIV therapy, and we are pleased to be able to offer this option to a broad range of appropriate adult and pediatric patients weighing at least 40 kg who are living with HIV,” Dr. Eliav Barr, senior vice president, global clinical development, infectious diseases and vaccines, Merck Research Laboratories, said in a prepared statement.