ABSTRACT
This chapter describes the toxicities that may be encountered with these new agents. The toxicities will be primarily graded according to the National Cancer Institute Common Toxicity Criteria. In phase I clinical trials in patients with solid tumors, the dose-limiting toxicity of fludarabine was myelosuppression, particularly leukopenia, with profound lymphocytopenia. Care needs to be exercised to avoid combining the nucleoside analogs with drugs that have overlapping or synergistic toxicities, particularly neurotoxicity. Tumor lysis syndrome with the purine analogs has been primarily reported as anecdotal cases or occasional patients on clinical trials. At the high doses of Chlorodeoxyadenosine used in the early phase I trial, gastrointestinal toxicity occurred in 8 of the 31 patients reported by E. Beutler and coworkers. Dyspnea, occasionally with pulmonary infiltrates, has been reported with each of the nucleoside analogs. Prevention of infections associated with purine analog therapy is a major therapeutic challenge.
