Salvage therapy with thalidomide in multiple myeloma patients relapsing after autologous peripheral blood stem cell transplantation.

BACKGROUND AND OBJECTIVES: The introduction of high-dose therapy with stem cell support has significantly improved the outcome of patients with multiple myeloma (MM) in terms of increased complete remission (CR) rate and extended survival, both disease-free and overall. Few options, however, are presently available for patients who relapse after single or double autologous stem cell transplantation (SCT). Thalidomide, a glutamic acid derivative with anti-angiogenetic properties, has been recently proposed as salvage treatment for such patients. The present study was aimed at evaluating thalidomide as single agent therapy for patients who had previously received autologous peripheral blood stem cell transplantation. DESIGN AND METHODS: From October 1999 to August 2000, 11 patients (7 males/4 females) who had relapsed after single (n = 4) or double (n = 7) autologous peripheral blood SCT were enrolled in the trial. Thalidomide, always employed as a single agent, was initially administered at a dose of 100 mg/day; if well tolerated, the dose was increased serially by 200 mg every other week to a maximum of 800 mg/day.
RESULTS: The median administered dose was 600 mg/day. WHO grade > II toxic effects were constipation, lethargy, and leukopenia. Four patients (36%) showed > 50% reduction in serum M protein concentration and 4 showed > 25% reduction, for a total response rate averaging 72%. After a median follow-up of 5 months, 3 out of 8 responding patients are alive and progression-free and 5 patients have relapsed. INTERPRETATION AND CONCLUSIONS; These data confirm that thalidomide is active in poor-prognosis MM patients such as those relapsing after autologous SCT, and could thus deserve further testing in combination therapy.