Hexamethylmelamine and prednisone in the treatment of refractory multiple myeloma

Hexamethylmelamine (280 mg/m2) daily for 21 days every 28 days was given, with prednisone 75 mg on days 1-7, to patients with multiple myeloma failing to respond to, or relapsing from, previous therapy. All patients had received the same dose of prednisone in their previous treatment regimen. Among 65 evaluable patients, 35% achieved a response of some objective improvement or better. An additional 19% showed stabilization of progressive disease. Responses were achieved both in patients resistant to initial therapy and those relapsing after a response. Median survival was 10.3 months for the entire group with responding patients having significantly longer survival than nonresponders. The major toxicities are gastrointestinal and neurologic with hematologic toxicity less severe. The drug appears to have true antimyeloma tumor effect and warrants consideration for further study in combination with other agents in initial treatment.