A "bumper crop" of new AIDS medicines being developed in laboratories or already in human trials is fueling hopes among researchers that a new era of treatment is dawning, seven years after powerful drug cocktails significantly improved the survival rate for patients.
Scientists attending the nation's premier gathering of AIDS specialists, in Boston, revealed details of at least 10 promising drugs that would substantially expand the arsenal of medicines available to thwart the virus.
With the development of these drugs, researchers can attack the AIDS virus at eight different points, making it harder for the resilient bug to build up a resistance to treatment.
"The pipeline of new drugs has an impressive number of candidates in it," said Dr. John Mellors, chief of infectious diseases at the University of Pittsburgh.
"This is something we haven't seen in many years. I would say this is a bumper crop."
In the pipeline
Mellors estimated that a half-dozen drugs in clinical trials can potentially help patients who are no longer helped by existing AIDS pills. That compares with just one or two new drugs in clinical trials a few years ago.
Similarly, he and a panel of researchers concurred that 10 to 12 more medicines are in early phases of study, four times as many as in recent years.
One measure of how far scientists have advanced: One AIDS medicine, T-20, is still awaiting Food and Drug Administration approval, but already researchers are developing a related drug to use if a patient's virus outsmarts the initial formulation.
But a leading Boston researcher who regularly guides clinical trials of AIDS drugs warned that while early results might warrant optimism, the path from research bench to patient is pocked with disappointment.
The drugs will take several years to win approval and even then they can produce side effects never anticipated by researchers, said Dr. Calvin Cohen, research director of Community Research Initiative of New England.
"It's wonderful to see the drug industry looking and to see some of these results," said Cohen, who is also research director for Harvard Vanguard Medical Associates.
"But it's also important not to rely on new drugs to get us out of this mess."
Discovering new drugs has acquired new urgency as patients whose lives have been prolonged find that their medicines no longer work.
Virus grows stronger
And drug resistance is increasingly common among patients newly diagnosed with the AIDS virus: A study last year found that one in eight of the newly infected carry a virus already beyond the reach of at least one drug.
Among the prospective medicines garnering the most attention at the 10th Conference on Retroviruses and Opportunistic Infections is one studied, in part, by scientists at Brigham and Women's Hospital as well as Beth Israel Deaconess Medical Center.
Dr. Daniel Kuritzkes of Brigham told scientists that while results are preliminary, his team is optimistic about the potential of a drug named TNX-355.
Early human trials of TNX-355 showed that HIV levels dropped by as much as 97 percent in some patients.
Making the drug especially appealing to researchers - and patients - is that it's given in a single IV dose, remaining potent for as long as two or three weeks.
"Remember when we had to take [drugs] every eight hours?" Mellors said. "We're entering the period of taking only a few pills a day."
The advances in drug development come even as AIDS specialists cautioned that the virus appears to be spreading in the United States with renewed vigor.
Increase in cases
In 2001, for the first time since 1993, federal disease trackers recorded an overall increase in AIDS cases. Though that rise was slight - just 1 percent - researchers recognize that the virus is striking certain communities with disproportionate fury.
One study documented a 14 percent increase in HIV diagnoses among men who had sex with men between 1999 and 2001.
"It's very important to keep reminding the American public that HIV/AIDS is still a serious problem in our own country," said Dr. Ronald O. Valdiserri, a top AIDS specialist at the federal Centers for Disease Control and Prevention.
Researchers in North Carolina report that up to one of every five people infected with HIV in the United States passes through a prison or jail every year.
But researchers do not believe those infections are acquired while incarcerated. Instead, inmates enter jail already infected.
It's their behavior upon release that alarms scientists. Nearly one-third of inmates interviewed by researchers said they thought it was likely they would infect a partner who did not have the virus.
"When people get out of prisons," said Dr. David Wohl, the University of North Carolina researcher who directed the study, "there's two things people want to do, and one of them is get a Big Mac."