ICN's VIRAZOLE (RIBAVIRIN) PROTOCOL FOR A 700-PATIENT STUDY

ICN's VIRAZOLE (RIBAVIRIN) PROTOCOL FOR A 700-PATIENT STUDY in HIV-positive, asymptomatic patients is currently under review at FDA, the company announced at a July 14 symposium on ribavirin. "A final protocol based on discussions between the U.S. FDA and ourselves has been submitted to that agency for its final consideration," Viratek Acting Director Roberts Smith, PhD, said. The protocol, which was submitted to the agency the week of July 11-15, calls for a placebo control and a starting dose of 1,200 mg of drug, the ICN subsidiary said. The study will be conducted in no less than six centers and may include the National Institute of Allergy & Infectious Diseases' AIDS Treatment Evaluation Units (ATEUs). Smith noted that the protocol for the U.S. ribavirin study is similar to a protocol developed for an ICN-sponsored Canadian and Australian study. That investigation will also involve 700 HIV positive, asymptomatic patients and "will get under way shortly," Smith said. He added that the protocol is now being reviewed by the Canadian Health Protection Branch. ICN's seminar was part of the National Conference on HIV, held July 14-16 in Washington, D.C. The conference was jointly sponsored by the Centers for Disease Control, Walter Reed Army Institute of Research, American Red Cross, and Americans for a Sound AIDS Policy. Ribavirin is also being studied in combination with isoprinosine for treating HIV-positive, asymptomatic patients at an ongoing three-month study at George Washington University's medical school, Smith pointed out. Richard Shulof, MD, noted that seven patients have been enrolled so far and that five of the seven have received treatment for two months without side effects. Ribavirin is also being evaluated in tolerance studies. NIAID is currently sponsoring a tolerance study in four ATEUs, Smith noted. Richard Roberts, MD, at Cornell Medical Center "has just about completed a major tolerance study of ribavirin in HIV positive people, wherein the dose is raised considerably, in fact it goes up to 2,400 mg." The investigator received approval on Oct. 16 to proceed with the study of 32 patients with LAS and ARC ("The Pink Sheet" Oct. 26, 1987, T&G-2). The IND authorization lifted a clinical hold placed on ICN's trials because of safety concerns stemming from increased mortality in the drug group during the ARC study. Smith also mentioned that a ribavirin tolerance study in children that has just been completed at a children's hospital in New Jersey. "The drug was well tolerated and currently there are discussions in the National Institutes of Health as to whether or not to proceed with with treatment of children with HIV infections," he said. The submission of a protocol for a U.S. trial of ribavirin could be ICN's third attempt to gain a Treatment IND for the drug. Twice, FDA has rejected the company's request for a Treatment IND. The first time was in April 1987 and the second was in August ("The Pink Sheet" Sept. 7, p. 11). FDA had denied ICN's original request for a Treatment IND because the agency determined that the Phase II LAS study was imbalanced. ICN recently submitted a combined statistical analysis of both the original ribavirin LAS and ARC studies to the agency, which the company conducted in response to FDA's conclusion that the patients may have been classified incorrectly. Viratek VP-Statistics and Data Management Alan Forsythe, PhD, explained the analysis: "What we're going to do is reclassify the patients based on entry material as reported in the case report forms. We're going to see how the results from last year, which suggested efficacy, are influenced by changes in those classifications." From the analysis, Forsythe concluded, "the effect of ribavirin is not likely due to the classification of patients at baseline" and therefore, further trials of ribavirin in the treatment of AIDS are important.