A drug used to treat herpes can increase the life expectancy of patients in the end-stages of AIDS by up to 1 1/2 years if used in conjunction with the anti-viral AZT, says a study by researchers at Johns Hopkins University School of Hygiene and Public Health.
The study, released today in the Annals of Internal Medicine, included 786 HIV-positive men who were taking AZT. Among those patients, 488 took the anti-herpes drug, acyclovir, either to combat herpes or to treat HIV. The others took AZT alone.
AIDS patients who began taking the combination therapy when they were diagnosed with very low levels of certain types of white blood cells critical to the function of the immune system, lived about 1,018 days beyond that diagnosis, he said.
Patients with the same blood counts who didn't take the two drugs survived only 544 days.
The study, funded by the National Institutes of Health as part of a long-term investigation of HIV in gay and bisexual men, was also conducted at Northwestern University and the University of Pittsburgh. Both drugs, acyclovir and AZT, are manufactured by Burroughs Wellcome.
These results confirm data from two previous clinical trials conducted in Europe and in Australia, said Dr. Neil Graham, an author of the journal article.
"Somewhat to our surprise, we found the same thing as in the two other studies," he said. "So I think there is enough evidence to recommend combining AZT and acyclovir in patients who have a history of herpes."
Certain forms of herpes are extremely common in sexually active adults.
Nearly 100 percent of gay men have either the antibodies for herpes or have shown symptoms of herpes, said Dr. Graham, an associate professor in the Hopkins epidemiology department.
In other segments of the population, the prevalence of herpes may range from 10 percent to 80 percent.
Acyclovir helps herpes patients in two ways, said Dr. Graham. It controls the replication of the herpes virus and it allows the patients, who often have lesions on the mouth or in the genital area, time to heal. However, the drug suppresses, rather than kills, the herpes virus.
In both test-tubes and in studies in humans, herpes simplex seems to exacerbate the progress of HIV. Acyclovir may help AIDS patients by stopping this effect, he said.
The study also showed that lower doses than previously thought could benefit AIDS patients.
As little as 600 to 800 milligrams a day of acyclovir were enough to improve the survival rate of study participants, said Dr. Graham. In earlier studies, as much as 3,200 milligrams a day were administered.
The study did not address whether acyclovir could help AIDS patients who cannot take AZT.
"We don't know if this effect would be just as strong in those patients," Dr. Graham said. "The ideal would be to combine the acyclovir, which suppresses herpes, with [AZT], which suppresses HIV; then you would have a double-sided attack on the disease."