Side effects and efficacy of thalidomide and low dose dexamethasone combination in newly diagnosed symptomatic multiple myeloma patients in India—A pilot study

Abstract

19530 Background: The standard schedule of thalidomide and dexamethasone combination in untreated myeloma includes three pulses (each of four days with 40 mg per day) of dexamethasone and thalidomide 200 mg/day every 28 days. Poor tolerance to this schedule, low feasibility of stem cell transplant, uncertain access to myeloma care resources and higher rate of infections and hyperglycemia are the limitations in our clinical setting. We undertook a phase II, one stage study of low dose dexamethasone and thalidomide as initial treatment of myeloma with the primary end point of establishing the adverse effect profile of this combination. The secondary end point was evaluation of efficacy. Methods: Twenty consecutive patients of untreated myeloma were treated with thalidomide 200 mg/day with dexamethasone 40 mg per day D1 to D4 every 21 days. Patients were evaluated after 3rd and 6th cycles. Zolendronic acid was given monthly. Antithrombotic prophylaxis and erythropoietin were not routinely used. Patients were monitored for thrombosis, neuropathy and other known adverse effects. Results: There was no occurrence of thrombosis, skin rash, bradycardia or deaths. There were no grade 3 or 4 toxicities except one patient who had grade 3 constipation after 6 cycles. All patients (100%) had grade 2 constipation at the end of three cycles and 13/20 (65 %) after 6 cycles. At the end of 3rd and 6th cycles, 50 % of patients had grade 2 sensory neuropathy and 95 % developed grade 2 fatigue. Sixteen of the 20 patients (80%) had a response to therapy after 3 cycles and 19 of the 20 patients (95%) after 6 cycles. At the completion of 6 cycles, four patients (20 %, 95% CI 2 -37 %) had CR, six had VGPR (30 %, 95% CI 1 -50 %) and PR was seen in nine patients (45%, 95 % CI 23 to 66%). Conclusions: For the initial treatment of myeloma low dose dexamethasone with thalidomide seems well tolerated with minimal grade 3 and 4 toxicities. It is effective and feasible in our patient population. It merits further study with and formal comparison with high dose dexamethasone regimen. No significant financial relationships to disclose.