Who Owns Isentress?

Isentress (raltegravir) was developed by Merck and Co. through its infectious diseases research program. The drug's development was led by Daria Hazuda, a Merck researcher who led the team that discovered HIV integrase inhibitors at Merck Research Laboratories. Hazuda's team identified the mechanism by which HIV integrase inserts viral DNA into the host cell genome and developed compounds that could block this process.

The FDA approved Isentress on October 12, 2007, for use in combination with other antiretroviral agents for the treatment of HIV-1 infection in treatment-experienced patients. The approval was based on data from the BENCHMRK-1 and BENCHMRK-2 clinical trials, which demonstrated that Isentress, when added to an optimized background regimen, significantly reduced HIV viral load compared to placebo in patients with documented resistance to multiple antiretroviral drug classes.

Isentress was the first integrase strand transfer inhibitor (INSTI) to receive FDA approval. This was a significant milestone in HIV treatment because integrase inhibitors represented a new mechanism of action against HIV, distinct from existing drug classes including protease inhibitors, non-nucleoside reverse transcriptase inhibitors, and entry inhibitors. The introduction of Isentress provided a new treatment option for patients who had developed resistance to other antiretroviral medications.

In July 2009, the FDA expanded Isentress approval to include treatment-naive patients (those beginning HIV treatment for the first time), based on data from the STARTMRK trial. This expansion significantly broadened the drug's market. The STARTMRK trial demonstrated that Isentress was non-inferior to efavirenz, a widely used non-nucleoside reverse transcriptase inhibitor, when both were combined with tenofovir and emtricitabine.

In 2017, the FDA approved Isentress HD (raltegravir 600mg), a higher-dose formulation that allowed for twice-daily dosing with fewer tablets. The original Isentress 400mg required twice-daily dosing with one tablet per dose, while Isentress HD allowed for twice-daily dosing with a single 600mg tablet. A once-daily formulation was also studied but did not demonstrate equivalent efficacy in clinical trials.

Isentress received the Prix Galien USA Award in 2008 in the category of Best Pharmaceutical Agent. The Prix Galien is considered the pharmaceutical industry's equivalent of the Nobel Prize, recognizing significant advances in drug development. The award acknowledged Isentress as the first-in-class integrase inhibitor that expanded HIV treatment options.

Isentress was added to the World Health Organization's List of Essential Medicines, which identifies medications considered most important for public health. The WHO recommended integrase inhibitors as preferred first-line treatment options in its 2016 HIV treatment guidelines, which further established the drug class that Isentress pioneered.

As Isentress's patents approached expiration, generic manufacturers began developing raltegravir versions. Merck's key patents for raltegravir expired in the United States in 2021 and in Europe in 2022. Generic raltegravir became available in several markets following patent expiration, leading to significant revenue decline for the Isentress brand. Merck has shifted its HIV strategy toward newer pipeline products while continuing to sell Isentress in markets where generic versions are not yet available.