New hope for HIV patients from Merck, Pfizer

NEW YORK (CNNMoney.com) -- Merck and Pfizer are giving AIDS patients something to hope for: a new generation of experimental drugs that could prolong their lives.

"The most desperately ill patients are getting a second chance," said Dr. Jacob Lalezari, assistant professor at the University of California, San Francisco, and lead researcher in the study for Pfizer's Maraviroc.

Pfizer (down $0.12 to $25.02, Charts) announced that its experimental drug Maraviroc helped twice as many HIV patients halt the spread of the virus in infected people when added to other AIDS therapies, compared to those who took the therapies without Maraviroc.

Maraviroc was filed with the Food and Drug Administration in December and has been granted fast-track review status. If approved, it could end up on the market this summer. Pfizer made the announcement Tuesday night, and the company's stock price rose about 1 percent in Wednesday morning trading.

In a separate study, Merck (up $1.09 to $44.27, Charts) said that more than three out of four patients taking its experimental drug Isentress (more widely known by its scientific names MK-0518 and raltegravir) were able to suppress the spread of human immunodeficiency virus when added to other HIV drugs.

"The drug performed very well," said Dr. Robin Isaacs of Merck. "We're very excited about the results."

Dr. Isaacs said that Isentress would be filed with the Food and Drug Administration during the second quarter of 2007. He said the drug has been tested in patients who were previously treated for AIDS with other medications but "has the potential for a much wider population."

Despite the strong data, analysts do not expect these drugs to be billion-dollar blockbusters because HIV drugs are often given away or are provided at cut-rate prices. About two-thirds of the approximately 40 million AIDS patients worldwide live in sub-Saharan Africa, and many of them are too poor to afford the drugs.

Barbara Ryan, analyst for Deutsche Bank North America, projects peak annual sales of up to $700 million each for the Merck and Pfizer drugs. Les Funtleyder, analyst for Miller Tabak, projects peak sales of up to $400 million for Isentress and $200 million for Maraviroc.

Merck's stock price jumped about 3 percent in Wednesday trading, after the company made another announcement, raising its first-quarter earnings guidance to 63 to 67 cents a share. This exceeds the analysts' average expectation of 60 cents, according to Reuters Estimates.

"We believe this announcement speaks to the positive momentum in Merck's core business," wrote Funtleyder in a published note. He attributed Merck's improved earnings guidance to less than expected sales erosion from the 2006 patent loss of the anticholesterol drug Zocor, countered by strong sales from Vytorin (a cholesterol-cutting combo produced with Schering-Plough (up $0.20 to $23.56, Charts)), the asthma medication Singulair and newly released products.

AIDS was once considered a death sentence, but this is no longer the case for patients with access to the best medicines, who can often postpone by decades the fatal breakdown of their immune systems.

"HIV has gone from a holocaust, a killer, to a very chronic and manageable disease," said Dr. Lalezari, the independent researcher who lead the Maraviroc study. "I often tell my patients that they're going to have find something else to die from."

The up-and-coming integrase inhibitors from Merck and Pfizer are designed to suppress the spread of the AIDS virus. In theory, they could supplement or replace an older class of life-prolonging drugs called protease inhibitors, introduced in the 1990s.

"If you had HIV and you could survive until 1997 when the protease inhibitors arrived, then you had a pretty good chance of still being alive today," said Dr. Lalezari.

The introduction of new drugs is considered essential because HIV is a constantly mutating virus that develops resistance to the older therapies. Also, patients who survive for years while taking AIDS drugs will often develop resistance to the drugs that keep them alive.

The companies unveiled the HIV data Tuesday night at the annual Conference of Retroviruses and Opportunistic Infection in Los Angeles.

Johnson & Johnson (down $0.04 to $63.01, Charts) announced the results of an AIDS drug trial at the conference on Wednesday. Johnson & Johnson said that a midstage trial showed that its experimental HIV drug, called TMC278, worked as well Bristol-Myers Squibb's (up $0.03 to $26.39, Charts) drug Sustiva in patients who had not been previously treated, according to Reuters.

Gilead Sciences (up $0.69 to $71.27, Charts) also unveiled midstage study results at the conference on Wednesday for its AIDS drug. Gilead announced that the highest doses of its experimental drug GS-9137 lowered levels of the virus, according to Reuters.

The studies from Johnson & Johnson and Gilead are less advanced than the ones announced by Merck and Pfizer, so the potential market entry for their drugs is still years away.

The analysts quoted for this story do not own shares in the companies mentioned here, but Deutsche Bank North America might make a market in Merck or Pfizer.

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