EXPERIMENTAL AIDS THERAPIES
At the Sixth International Conference on AIDS, new data was presented on many experimental therapies. These are some of the highlights.
* DDI, or dideoxyinosine. This compound, which has similarities to AZT, the only drug approved for treatment of HIV infection, interferes with the ability of the virus to reproduce. DDI has now been studied in patients at the National Cancer Institute for up to 21 months. Lower doses are “well tolerated and . . . can induce sustained clinical, immunologic and virologic improvements,” a research team led by Dr. Robert Yarchoan said.
Across the country, about 1,000 patients are involved in trials comparing DDI and AZT and an additional 10,000 patients are receiving DDI under an expanded access program. Pancreatitis, a potentially fatal complication of DDI therapy , remains a serious concern. But researchers hope many cases can be avoided by screening out the individuals most likely to develop the problem and closer monitoring of patients.
* DDC, or dideoxycytidine. DDC is another compound similar to AZT. It is also entering large trials and is about to become available under an expanded access program. According to Dr. Thomas Merigan of Stanford University, treatment regimens alternating DDC with AZT hold promise for sustaining immunologic improvements and reducing the incidence of severe nerve pains, a key DDC side-effect.
* Ditiocarb, or Imuthiol. In a 387-patient placebo-controlled trial coordinated by Dr. Evan Hersh of the University of Arizona, this immune system stimulant reduced the number of new opportunistic infections in patients with AIDS and related conditions. Preliminary results from a two-year European study of 1,600 asymptomatic HIV-infected individuals are expected later this year. Further studies of ditiocarb in conjunction with AZT are planned in patients with advanced HIV disease.
* Recombinant CD4-immunoglobulins. These antibody-like hybrids are designed to block the entry of HIV into immune system cells. They appear to be safe but to date little evidence of effectiveness has been found. Studies with larger doses are continuing.
* Alpha interferon. Alpha interferon is a naturally occurring human protein that can boost the immune system and interfere with assembly of HIV particles. Updated studies from the National Institute of Allergies and Infectious Diseases indicated that while the protein is ineffective in advanced HIV disease, it may help patients with more intact immune systems. Alpha interferon is already approved for use in HIV-infected individuals with Kaposi’s sarcoma.
* HIV-immunogen. The AIDS immunization therapy developed by Dr. Jonas Salk, the polio vaccine pioneer. The 86 patients treated at USC Medical School in Los Angeles “remain alive and clinically well” at a median follow-up of more than two years, according to Dr. Alexandra Levine. Five patients, however, have developed serious infections or tumors. Large-scale placebo controlled efficacy trials of the combination of HIV-immunogen and AZT will begin within the next several months.
