Intensive cyclophosphamide (NSC-26271) therapy for solid tumors.

Area of Science:

• Oncology
• Pharmacology
• Cancer Treatment

Background:

• Cyclophosphamide (CY) is an alkylating agent used in cancer therapy.
• Its efficacy in nonlymphoid solid tumors, particularly refractory ones, requires further investigation.
• Dose-response relationships and toxicity profiles need evaluation.

Purpose of the Study:

• To evaluate the efficacy and toxicity of two different dose schedules of cyclophosphamide in patients with nonlymphoid solid tumors.
• To determine if higher doses of cyclophosphamide improve antitumor response in refractory malignancies.

Main Methods:

• Twenty-five patients with various nonlymphoid solid tumors received cyclophosphamide.
• Two dose schedules were used: 60 mg/kg and 100 mg/kg.
• Patients were monitored for tumor response, leukocyte and platelet counts, and toxicities.

Main Results:

• Partial responses were observed in two patients at 60 mg/kg and two at 100 mg/kg.
• Higher dose (100 mg/kg) led to significantly lower nadir leukocyte counts and increased infectious complications, including bacteremia and sepsis.
• Nonhematologic toxicities, including potential myocardial effects, were noted with the higher dose.

Conclusions:

• Intensive cyclophosphamide therapy did not demonstrate an increased antitumor response in these solid tumors.
• The higher dose schedule (100 mg/kg) was associated with increased hematologic toxicity and infectious complications.
• Cyclophosphamide may have limited utility in nonlymphoid solid tumors refractory to alkylating agents.