FDA Approves New Labeling for Merck Blockbuster HIV Drug ISENTRESS

By Gene Quinn
July 10, 2013

On July 1, 2013, Merck (NYSE: MRK) announced that the U.S. Food and Drug Administration (FDA) has approved new labeling for ISENTRESS® (raltegravir) Film-coated Tablets. The primary purpose of the FDA labeling requirements and regulations is to give healthcare professionals the information they need to prescribe drugs appropriately. See An Introduction to the Improved FDA Prescription Drug Labeling.

ISENTRESS is Merck’s integrase inhibitor for the treatment of HIV-1 infection in adult patients as part of combination Human Immunodeficiency Virus (HIV) therapy. It is the first and only integrase inhibitor approved by the FDA. ISENTRESS had sales of $243,636,000 during Q1 of 2013, and has experienced growth quarter over quarter, which means that ISENTRESS is flirting with the $1 billion per year in sales that would make it a blockbuster drug. See Isentress Sales Data. The FDA approving new labeling seems likely to guarantee that during FY 2013 ISENTRESS will achieve blockbuster status.

The Food and Drug Administration (FDA), originally approved ISENTRESS on October 12, 2007, granting accelerated approval for raltegravir tablets (400 mg) for treatment of  HIV-1 infection in combination with other antiretroviral agents. ISENTRESS received a priority review by the FDA, with the review and approval of the New Drug Application being completed within six months. At the time of the initial approval the FDA explained that when ISENTRESS is used with other anti-HIV medicines, it “may reduce the amount of HIV in the blood and may increase white blood cells, called CD4+ (T) cells, that help fight other infections.”

This newly approved, updated prescribing information for ISENTERSS now includes 240-week results from the STARTMRK study, the double-blind Phase III study that evaluated integrase inhibitor in previously untreated adult patients with HIV-1 infection. The results show that the regimen containing ISENTRESS in combination therapy demonstrated long-term viral suppression and a greater immunologic response than conventional treatment regimens, as well as a proven, long-term safety and tolerability profile through 240 weeks in previously untreated adult HIV-1 infected patients.


“As the care of HIV evolves, ISENTRESS continues to be an important treatment option for adult patients with HIV-1,” said Jürgen Rockstroh, M.D., University of Bonn, Bonn-Venusberg, Germany. “These 240-week results are important for physicians to consider when initiating treatment with ISENTRESS in combination therapy in treatment-naïve adult patients with HIV-1.”

ISENTRESS is an integrase inhibitor indicated in combination with other antiretroviral (ARV) agents for the treatment of HIV-1 infection in adults. According to the Merck website the drug is covered by U.S. Patent No. 7,169,780 and U.S. Patent No. 7,754,731.

The ‘780 patent explains that the invention is “directed to N-substituted 5-hydroxy-6-oxo-1,6-dihydropyrimidine-4-carboxamides and pharmaceutically acceptable salts thereof, their synthesis, and their use as inhibitors of the HIV integrase enzyme.” The patent further explains that the compounds and pharmaceutically acceptable salts “are useful for preventing or treating infection by HIV and for treating or delaying the onset of AIDS.” Still further, the patent states that the “invention further includes… methods of delaying the onset of AIDS, methods of preventing AIDS, methods of preventing infection by HIV, and methods of treating infection by HIV.”

The ‘731 patent explains that the invention relates to “processes for preparing potassium salts of Compound A and methods of using the Compound A salts for inhibiting HIV integrase, for treating or prophylaxis of HIV infection, and for treating, prophylaxis of, or delaying the onset of AIDS.”

The ‘780 patent is set to expire on October 3, 2023 and the ‘731 patent is set to expire on March 11, 2029. See Generic Isentress

The Author

Gene Quinn

Gene Quinn is a Patent Attorney and Editor and President & CEO ofIPWatchdog, Inc.. Gene founded IPWatchdog.com in 1999. Gene is also a principal lecturer in the PLI Patent Bar Review Course and Of Counsel to the law firm of Berenato & White, LLC. Gene’s specialty is in the area of strategic patent consulting, patent application drafting and patent prosecution. He consults with attorneys facing peculiar procedural issues at the Patent Office, advises investors and executives on patent law changes and pending litigation matters, and works with start-up businesses throughout the United States and around the world, primarily dealing with software and computer related innovations. is admitted to practice law in New Hampshire, is a Registered Patent Attorney and is also admitted to practice before the United States Court of Appeals for the Federal Circuit. CLICK HERE to send Gene a message.

Warning & Disclaimer: The pages, articles and comments on IPWatchdog.com do not constitute legal advice, nor do they create any attorney-client relationship. The articles published express the personal opinion and views of the author as of the time of publication and should not be attributed to the author’s employer, clients or the sponsors of IPWatchdog.com. Read more.

Discuss this

There are currently No Comments comments.