DDI BELOW 9.6 MG/KG PER DAY WAS "WELL TOLERATED"

DDI BELOW 9.6 MG/KG PER DAY WAS "WELL TOLERATED," according to results from a Phase I trial conducted by National Cancer Institute's Robert Yarchoan, et al. The extended Phase I study of 58 patients with AIDS or AIDS-related complex was published in the Sept. 1 issue of Lancet. Bristol-Myers Squibb's dideoxyinosine (ddI) is currently widely available to AIDS patients under FDA's "parallel track" system. The authors found that doses above 9.6 mg/kg per day were frequently associated with peripheral neuropathy, pancreatitis, or hepatitis, while doses of 9.6 mg/kg per day or below "were well tolerated for up to 21 months." None of the patients died of drug toxicity in the study. The authors noted that three patients with underlying disorders had seizures, adding that "the relation to ddI therapy is unclear." Milder reactions to the drug included anxiety, insomnia, irritability, headaches and transient abdominal pain. The study included 37 patients who were enrolled in NCI's initial Phase I study that began in July 1988. The researchers analyzed 13 of these patients who entered the study at 3.2-9.6 mg/kg of ddI and received the drug for a median of 17 months. The authors stated that among these patients, statistically significant increases in CD4 lymphocytes "persisted for at least nine months." The researchers also noted that the immunological and virological improvements in patients receiving ddI can "persist for at least nine months, and in some patients up to 15 months." Yarchoan, et al., concluded that "overall, the results of this trial suggest that ddI (3.2-9.6 mg/kg per day) may be tolerated in most patients for long-term therapy and is associated with evidence of anti-HIV activity." However, the authors commented that "the optimum dose of ddI will not be known without further study." The authors added: "While few patients died, this extended Phase I study does not address the questions of whether ddI reduces disease progression or mortality in patients with HIV infection, or whether it is superior, equal, or inferior to zidovudine [AZT] as an anti-AIDS drug. The resolution of these questions will require carefully controlled clinical trials." The National Institutes of Health previously presented data from its Phase I ddI study in 28 AIDS and ARC patients at the International AIDS Conference in Montreal last year ("The Pink Sheet" June 12, 1989 T&G-6). The study found that ddI administration was associated with greater than 50% increases in CD4 counts in nine of 17 patients after six weeks of treatment and greater than 50% decreases in p24 antigen in eight of 12 patients with detectable p24 antigen upon entry into the study.