On May 30, 2017, the FDA approved Merck's 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
Adherence to therapy is one of the roadblocks of HIV treatment. However, by reducing the number of times drugs are to be administered, researchers are making an effort to increase adherence. In addition, 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,” said Dr. Eliav Barr, senior vice president, global clinical development, infectious diseases and vaccines, Merck Research Laboratories.
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 findings from the ONCEMRK phase 3 clinical trial
, which included 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 plus emtricitabine + tenofovir disoproxil fumarate. Although Isentress and Isentress HD can achieve viral suppression, the drugs do not cure HIV or AIDS, according to the press release.
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.
Through 48 weeks, only 3% of patients in both treatment groups discontinued therapy due to adverse events. This suggests that the drugs were, overall, well-tolerated. 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. However, Merck notes skin reactions that are potentially life-threatening have been reported with drug use, 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.
While Isentress HD was administered with emtricitabine + tenofovir disoproxil fumarate in the clinical trial, other 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.
“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.”
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