(Reuters)October 10, 1996: By Gene Emery-
A nationwide team of researchers reported Wednesday that a combination of drugs is better than the drug AZT alone for slowing the development of AIDS. But a second study released at the same time suggests that combination treatments offer no added benefit for patients whose immune systems have already been severely crippled with HIV.

In the first experiment, a group led by Dr. Scott Hammer of Harvard Medical School found that adding the drugs didanosine or zalcitabine to AZT therapy slowed the progression of the disease by more than 36 percent.

The second study, led by Dr. Louis Saravolatz of St. John Hospital in Detroit, involved sicker patients. The researchers found the drug combinations provided no added benefit.

The findings, published in today's New England Journal of Medicine, suggest that everyone infected with HIV should be getting anti-AIDS medicine, especially once a test that counts white blood cells shows the number of CD4 cells has dropped below 500, according to an editorial by Drs. Lawrence Corey and King Holmes of the University of Washington in Seattle.

The studies show AZT alone is no longer the best initial treatment for HIV. Instead, they suggest the best way to assess the progress of infection and gauge the effectiveness of treatment is to measure the amount of HIV circulating in the blood. The standard method is to count CD4 white, or T-cells in a tiny volume of blood.

In the Hammer study, the researchers randomly assigned 2,467 people nationwide to receive AZT alone, AZT plus zalcitabine, AZT plus didanosine, or didanosine alone. All the volunteers had CD4 counts under 500, which is thought to indicate some compromise of the immune system.

AZT is sold under the brand name Retrovir. Didanosine is sold as Videx. Zalcitabine is sold as Hivid.

The researchers then assessed how many volunteers progressed to one of three negative benchmarks: development of AIDS,a 50-percent drop in their CD4 count or death. Among AZT recipients, 32 percent hit one of those benchmarks, compared to 22 percent who took didanosine alone, 18 percent who took AZT plus didanosine and 20 percent who got AZT plus zalcitabine.

In the Saravolatz study, the 1,102 volunteers nationwide had CD4 counts below 200, which usually signifies HIV is more advanced. The researchers found it made little difference which drug combination the patients received. There was no statistically significant decline in the benchmarks.