HEM Pharmaceuticals is betting on the ability of its double-strandedRNA drug Ampligen to activate the body's immune system to fightHIV infection -- even in people who are HIV-positive but have notadvanced to the late stages of the disease.

Theoretically, at least, this approach should work even if theparticular strain of HIV has become resistant to the commonly usedanti-viral drug AZT.

Researchers from HEM of Philadelphia reported this week at the33rd Interscience Conference on Antimicrobial Agents andChemotherapy (ICAAC) that Ampligen is indeed active against AZT-resistant HIV in vitro, and also seems to enhance the ability of AZT tofight viral infection in vivo.

In particular, the researchers isolated the AIDS virus from patientswho had been receiving the therapeutic drug AZT, and then analyzedthe virus' sensitivity to HEM's double-stranded RNA compound,which is the polymer Poly I:Poly C12U.

They found that virus isolated from AZT-treated patients was moreresistant to AZT than was wild-type virus, but it still remainedsensitive to the RNA drug. This held true for all isolates of the HIVthat the researchers tested.

Importantly, the combination of Ampligen and AZT showed noincreased toxicity to bone marrow when compared with AZT alone.

Moreover, HEM scientists also reported that HIV-positive patientsgiven a combination of Ampligen and AZT maintained a highernumber of functional CD4 cells than patients who received a placeboin a 48-week double-blinded clinical trial. The 36 patients in the trialall had CD4 lymphocyte counts of between 100 and 500 per milliliter.

-- Jennifer Van Brunt Senior Editor

(c) 1997 American Health Consultants. All rights reserved.