Federal Panel Urges Approval of New AIDS Drug

A federal advisory committee Thursday recommended government approval of a powerful new drug that recent research has shown can decrease or prevent AIDS-related complications and prolong life in very sick patients.

The drug, ritonavir, developed by Abbott Laboratories, is one of a new class of potent antiviral drugs called protease inhibitors that has excited AIDS specialists. Licensing by the Food and Drug Administration, which usually accepts its advisory committee recommendations, could come in a matter of weeks.

Researchers studying ritonavir said that, once on the drug, patients already very sick with AIDS suffered fewer symptoms and lived significantly longer than those taking a placebo.

However, committee members, troubled by the lack of information on patients with earlier-stage AIDS infection, approved the drug for use only in advanced cases. They urged the company to design further research in healthier infected populations to gain wider marketing approval.

Experts do not yet know how well protease inhibitors will work over the long term, particularly in infected individuals who have not yet developed symptoms. One of the problems with all AIDS drugs is the eventual development of viral strains that are drug-resistant. The long-term toxicity of the drug also is unknown.

Dr. Fred Valentine, the committee chairman and a professor in the department of medicine in the New York University Medical Center, said: “We have strong . . . data for the less advanced group,” but “we don’t have an application [from the company] for that group,” meaning that the company does not have research underway that would enable wider approval.

Company officials assured the panel that they were anxious to conduct the required research.

Once licensed, physicians can prescribe a drug any way they see fit, although insurance reimbursement could be a problem for unauthorized uses.

The rate of episodes of AIDS-related illnesses fell by two-thirds among those taking ritonavir in the study and the death rate was reduced by half, compared to a group receiving a placebo.

Results were seen more rapidly because patients in the trial already were extremely ill.

Until now, the most widely used AIDS drugs have been from a family known as nucleoside analogs, which are far less powerful. Both types of drugs attack the virus at different stages in its reproductive cycle. The nucleoside analogs are used to hit the replication process early in the disease, while protease inhibitors target a critical later phase.

The random, double-blind, placebo-controlled ritonavir study followed a total of 1,090 patients at 67 sites in the United States, Canada, Europe and Australia.

Thirteen percent of the 543 patients who received ritonavir died or experienced episodes of illness, compared with 27% of the 547 patients receiving a placebo. Episodes of illness dropped by two-thirds. Disease progression was defined as the onset of a new AIDS-related illness.

The death rate among patients receiving ritonavir was 4.8%, approximately half that of the 8.4% mortality rate of those on a placebo.