PARALLEL TRACK DRUG PROGRAM WOULD NOT BE NEEDED

PARALLEL TRACK DRUG PROGRAM WOULD NOT BE NEEDED if clinical trials were properly designed to include more patients from the start, FDA Office of Drug Evaluation I Director Robert Temple, MD, asserted at a recent meeting sponsored by FDA and the National Institute of Allergy and Infectious Diseases. "If we can design proper trials that exclude few patients and have a wide variety of trials for people with AIDS to enter into, including 'low-tech' trials, we don't need a parallel track," he said. "A parallel track is to a degree an admission of failure." Under the parallel track program, AIDS drugs entering Phase II clinicals would be available to people with AIDS who are ineligible to enter the trials. "We should try for the alternative," Temple urged. "Community-based trials in AIDS have been successful. These trials can work and physicians in practice can conduct high-quality clinical trials if they're given a chance." Temple was speaking at the AIDS Clinical Trials Symposium on Methodological Issues, held in Bethesda, Md. on Nov. 20. National Cancer Institute Biometry Branch chief David Byar also supported the concept of "low-tech" clinical trials that would have "broad entry criteria" and would involve minimal data monitoring. Byar maintained that the establishment of such trials could reduce the need for the parallel track system. Discussing possible ways to speed AIDS drug development, Byar suggested that Phase I and Phase II trials could be combined and that Phase II and Phase III trials also could be merged. He recommended that several drugs should be studied at the same time in randomized Phase II trials. Byar also noted that "there are situations where uncontrolled studies are justified in studying AIDS." Such situations could include, for example, "when there is no other treatment to use as a control, if the untreated patients will have substantial mortality and morbidity during the course of a clinical trial, and if the drug is not so toxic that the benefit might easily be outweighed by its harm," he said. The NCI branch chief added that an uncontrolled trial is justified if "there is sufficient experience with untreated disease to permit unambiguous evaluation of trial results," or "the scientific rationale for the treatment should be sufficiently strong that a positive result would be widely believed." In addition, Byar stated that he "strongly" believes that the "entry criteria for AIDS clinical trials have been far, far too restrictive." The "only purposes" for excluding people with AIDS from clinical trials "should be to determine which trials are best for which patients and to exclude patients that would be harmed by one or more of the therapies," Byar said. "Exclusion criteria are much more important in early trials in order to avoid confusing abnormal lab values with toxicity than they are in comparative Phase III trials." In a separate discussion on pediatric AIDS trials, NCI Pediatric Branch Chief Philip Pizzo advocated that Phase I pediatric trials should be started as soon as one month after the initiation of adult trials. Pizzo noted that the results of Phase II and Phase III trials in adults could be applicable to older pediatric patients. Another special population of AIDS patients, those intolerant to AZT, was also discussed at the meeting. J. Davis Allen, New England Deaconess Hospital, pointed out that up to 40%-80% of all AIDS patients may be intolerant to the drug after six months treatment with 1,200 mg of AZT per day.