An Efficacy Study of 2',3'-Dideoxyinosine (ddI) (BMY-40900) Administered Orally Twice Daily to Zidovudine Intolerant Patients With AIDS or AIDS-Related Complex

AMENDED: 8/29/90 Inclusion of asymptomatic patients with CD4 counts less than 200 cells/mm3. Standardization of baseline evaluation schedule to allow 14 days prior to study dosing. Reduction in frequency and intensity of follow-up evaluations. Standardization of study endpoints. Inclusion of toxicity scoring and management for amylase and triglyceride elevations. Clarification of concomitant medication use. Original design: To determine the effectiveness of didanosine (ddI) in patients with AIDS or advanced AIDS related complex (ARC) who have documented hematologic intolerance to zidovudine (AZT) therapy. To determine if the efficacy of ddI increases with increasing doses. AZT is effective in reducing mortality in patients with AIDS who receive the drug after the first episode of Pneumocystis carinii pneumonia (PCP) and in patients with advanced ARC. However, AZT therapy has been associated with significant toxicities. In addition, the effectiveness of AZT appears to decrease during the second and third years of therapy. For these reasons, the development of alternative therapy that would be at least as effective but less toxic is of great importance. The drug ddI is an antiviral agent that inhibits replication (reproduction) of HIV with less apparent toxicity than AZT. The major dose-limiting toxicities found in the Phase I studies have been pains in the feet and legs of 2 patients initially receiving 12 mg/kg/day and 12 patients receiving daily doses of 25.8 to 51.2 mg/kg; symptoms began 8 to 27 weeks after initiating ddI treatment. These neuropathy-like symptoms have generally not been associated with significant abnormalities in nerve conduction studies and patients have reported marked improvement in symptoms within 1 to 2 weeks of discontinuing ddI. Some patients have resumed ddI treatment at a reduced dose after resolution of their symptoms. Studies indicate that ddI remains active in the body for at least 12 hours. This indicates that benefits of ddI might be achieved with a low frequency of drug administration.

AZT is effective in reducing mortality in patients with AIDS who receive the drug after the first episode of Pneumocystis carinii pneumonia (PCP) and in patients with advanced ARC. However, AZT therapy has been associated with significant toxicities. In addition, the effectiveness of AZT appears to decrease during the second and third years of therapy. For these reasons, the development of alternative therapy that would be at least as effective but less toxic is of great importance. The drug ddI is an antiviral agent that inhibits replication (reproduction) of HIV with less apparent toxicity than AZT. The major dose-limiting toxicities found in the Phase I studies have been pains in the feet and legs of 2 patients initially receiving 12 mg/kg/day and 12 patients receiving daily doses of 25.8 to 51.2 mg/kg; symptoms began 8 to 27 weeks after initiating ddI treatment. These neuropathy-like symptoms have generally not been associated with significant abnormalities in nerve conduction studies and patients have reported marked improvement in symptoms within 1 to 2 weeks of discontinuing ddI. Some patients have resumed ddI treatment at a reduced dose after resolution of their symptoms. Studies indicate that ddI remains active in the body for at least 12 hours. This indicates that benefits of ddI might be achieved with a low frequency of drug administration. Patients are randomized to one of three ddI treatment groups; within each group, doses will be adjusted according to patient's weight at study entry. Stratification is by diagnosis of AIDS or AIDS related complex (ARC) and Medical Center. Data will be tabulated for the Data and Safety Monitoring Board at 3 month intervals.