News (Updated December 5, 2010)

[Home]  [Previous news]

Merck's HIV drug Isentress fails once-a-day study

Sat, Nov 20 2010

NEW YORK (Reuters) - Merck & Co said once-daily use of its HIV drug Isentress was less effective in a late-stage study than standard twice-daily dosing among patients that had not previously been treated for the virus that causes AIDS.

Based on the disappointing initial results, the U.S. drugmaker said on Monday it was ending the Phase III study, which could have paved the way for wider use among previously untreated patients.

The product is approved for use with other HIV medicines among previously treated patients as well as those that have not yet undergone treatment. It is the only approved HIV drug that works by blocking integrase -- an enzyme that enables the virus to insert its genetic material into human DNA.

"While a once-daily approval would have been an upside event that could have resulted in more first-line usage of Isentress over time, we do not see today's news as a major negative for (Merck's) stock," J.P. Morgan analyst Chris Schott said in a research note.

Merck shares were down 1.4 percent at $34.36 in early afternoon trading on the New York Stock Exchange, amid declines in the broad stock market.

Isentress is one of Merck's fastest-growing medicines. Its sales leaped 41 percent in the third quarter to $278 million, putting it on track to become a $1 billion-a-year blockbuster.

Schott held to his forecast of annual Isentress sales of $2 billion by 2015. But he said its later peak sales will be less than they might have been, had the trial not failed.

One group in the 775-patient study received 800 milligrams of Isentress once daily, along with other HIV treatments. Another group received the approved Isentress 400-milligram dose given twice a day, also in combination with standard treatments.

After 48 weeks, HIV was driven to undetectable levels in 83.2 percent of patients receiving the once-daily regimen, which was deemed inferior to the 88.9 percent of patients who received twice-daily tablets.

(Reporting by Ransdell Pierson; Editing by Tim Dobbyn)

Research Finds Not All HIV Affects Immune System Same Way

In some cases, virus has mutations that keep it from killing immune cells, study finds

Dec. 3, 2010 (HealthDay News) -- New research explains why immune function actually improves in a small number of patients with drug-resistant HIV.

In those cases, the virus has mutations that protect it against some HIV drugs but also thwart its ability to kill immune cells, explained the researchers at the Mayo Clinic in Rochester , Minn.

This is the first study to show that not all HIV is equally bad for the immune system, the authors noted.

"These findings suggest -- in contrast to how these patients have been treated in the past -- that changing treatments might not be needed in order to help the immune system," senior author and infectious disease researcher Dr. Andrew Badley, said in a Mayo news release.

The study is published in the Nov. 24 online edition of the journal PLoS Pathogens.

HIV causes AIDS by progressively killing CD4 T-cells that direct the immune system. The loss of these cells makes patients susceptible to infections and cancers. Over time, HIV can develop mutations that make it resistant to drugs. But only a few of those mutations also halt HIV's ability to kill immune cells, the researchers explained in the news release.

[Home]  [Previous news]