Caution needed in thalidomide therapy for myeloma

Although thalidomide treatment can be useful in certain patients with relapsed multiple myeloma, care is required to limit toxic side effects. Dr. Paul Richardson told Reuters Health, “we confirmed that thalidomide is active in patients with relapsed myeloma post stem cell transplantation, but side-effects can be dose-limiting and … are also cumulative.”

In the July issue of the Mayo Clinic Proceedings, Dr. Richardson of the Dana-Farber Cancer Institute, Boston, and colleagues report on their study of thalidomide therapy in 30 patients who had relapsed after high-dose chemotherapy and transplantation. They had previously undergone a median of 5 therapies. Daily thalidomide dosage started at 200 mg and escalated to 600 mg over 12 weeks. It was then continued at 200 mg per day for up to a year.The 12-week progression-free survival was 67% and responses, lasting a median of 6 months, were seen in 43% of patients.Nevertheless, dose escalation to 600 mg was achieved in only half of the patients. In fact, said Dr. Richardson, “most patients only tolerated doses between 200 and 400 mg.” In addition, in the majority of patients who responded to a dose of 600 mg and went on to the 200 mg maintenance level, there was subsequent disease progression. Constipation, rash and neuropathy were among dose-limiting side effects, and increased treatment-related toxicities were observed with longer durations of therapy. Overall, the researchers conclude that the optimal thalidomide dosage varies and “should be based on the individual patient to ensure that it well tolerated and that a response is achieved.”Dr. Richardson pointed out that “thalidomide analogs – such as lenalidomide, which we have studied – that have fewer side effects and greater potency, are showing promise.”(Source: Mayo Clin Proc 2004;79:875-882: Reuters Health: David Douglas: Oncolink: August 2004)