The U.S. Food and Drug Administration Friday approved a new type of HIV drug from Merck & Co. (MRK), a company spokeswoman said.
The drug, known by the brand name Isentress, was approved for use in patients who have failed treatment with other HIV drugs.
Isentress was approved as part of the FDA's accelerated-approval mechanism, which is aimed at getting life-saving treatments to market faster by allowing companies to submit less clinical data than usually required. Companies obtaining accelerated approval must keep studying drugs after they are on the market to gain full approval.
Isentress is designed to target one of three enzymes needed by HIV to reproduce. Current drugs on the market attack the other two enzymes, reverse transcriptase and protease. If approved, Isentress would be the only drug to target the third enzyme, known as integrase. Amy Rose, a Merck spokeswoman, said treatment with Isentress would cost about $9,850 per year.
Patients with HIV typically are treated with a "cocktail" of two or three types of drugs. However, over time, most HIV viruses mutate and stop responding to certain drugs, creating the need for new ones. Isentress is meant to be used in combination with other HIV drugs. There are more than 20 drugs currently on the U.S. market, according to the FDA.
Isentress was studied in patients who were on other HIV drugs including Roche Holding AG's (RHHBY) Fuzeon and Johnson & Johnson's (JNJ) Prezista, which was approved last year, for use in combination with Abbott Laboratories' (ABT) Norvir.
Two of the main studies of Isentress involved about 700 patients. About 460 received Isentress on top of other HIV drugs, while about 240 received a placebo, or fake pill, along with other HIV drugs. The studies showed that, after 16 weeks, slightly more than 60% of patients receiving Isentress had their HIV virus levels reduced to an undetectable level, compared with 33% to 36% of patients in the placebo group.
In an interview, Robin Isaacs, Merck's executive director of clinical research, said, "we are very excited about the drug. The (clinical) data look excellent."
With more than 20 HIV drugs on the market, one problem HIV doctors have is trying to figure out which combination of drugs works best, Isaacs said. The mix of various drugs typically keeps changing for each patient.
Isentress is a pill that is supposed to be taken twice a day and should be combined with other HIV drugs.
In August, the FDA approved another type of HIV drug, Selzentry, by Pfizer Inc. (PFE), that can be used in certain types of HIV patients. The drug inhibits one of two pathways that HIV uses to infect cells rather than treating the virus itself as other HIV drugs are designed to do. Another drug, by a Johnson & Johnson unit, currently known as TMC-125, is pending FDA approval and is also designed to be used by patients who have failed other HIV drugs.
During a review by an FDA advisory panel that looked at Isentress, the FDA said Isentress "appeared to be well-tolerated" and said few patients stopped taking the drug because of side effects. The agency said the benefits of the drug outweighed the potential risks of liver and muscle problems.
Merck shares closed on the New York Stock Exchange at $53.51, up 47 cents. In late trading, the stock was quoted at $54.40.