A genetically engineered drug that stimulates the body to produce new red blood cells significantly reduces the need for blood transfusions among some AIDS patients receiving the widely used drug AZT, researchers reported last week.

AZT depresses the ability of bone marrow to produce new red blood cells, a condition that requires frequent transfusions in about half of those receiving the drug.

Stimulating the patient's own blood production with a synthetic version of erythropoietin, a natural hormone that stimulates red blood cell production, may provide a solution, according to a report published last week in the New England Journal of Medicine. Some biotechnology firms make the hormone in large quantities by using genetic engineering techniques.

To test whether the hormone would work with AIDS patients, a research team led by Margaret Fischl of the University of Miami and financed by Ortho Pharmaceutical, which makes erythropoietin, was administered to 29 AIDS patients who were getting AZT; 34 patients receiving AZT got a placebo. During three months of treatment, erythropoietin reduced the need for transfusion to less than one unit per month in the treatment group. The group receiving a placebo required 2.74 units of blood per month. No side effects were reported.

The researchers concluded that "the use of even moderate amounts of erythropoietin may save large quantities of blood during a period of increasing need."