Thalidomide and Dexamethasone in Newly Diagnosed Multiple Myeloma.

PURPOSE: Thalidomide and dexamethasone has been shown to have excellent antimyeloma activity in both relapsed and newly diagnosed patients. This combination offers a potential oral, less toxic alternative to standard regimens. This retrospective study evaluates the activity of the combination of thalidomide and dexamethasone in patients with newly diagnosed multiple myeloma.

METHODS: Thirty-two patients with newly diagnosed multiple myeloma were treated with thalidomide and dexamethasone. The median age of the patients was 69yrs (range 46 to 83). The median serum paraprotein level was 38g/l (range 2 to 76g/l). The median bone marrow plasma cell percentage was 50% (range 10% to 99%) The first sixteen patients were commenced on thalidomide at 200mg od with the dose increased by 200mg every two weeks if tolerated to a maximum of 800mg od. The most recent sixteen patients were commenced on thalidomide at 100mg od with the dose increased to a maximum of 200mg if tolerated. All patients received dexamethasone 10mg qds 4-days-on/4-days-off for the first four weeks and for a four day pulse every four weeks subsequently.

RESULTS: Twenty-two of the thirty-two patients (69%) showed a greater than 50% reduction in serum paraprotein and/or urinary Bence Jones protein (BJP) from baseline. From the lower thalidomide dose group thirteen out of sixteen patients(81%) showed a greater than 50% reduction in serum paraprotein and/or urinary BJP from baseline compared with nine out of sixteen (56%) in the higher thalidomide dose group. Thirteen patients (40%) showed a reduction in serum paraprotein and/or urinary BJP of greater than 90%, eight from the lower thalidomide dose group and five from the higher thalidomide dose group. Six of the patients failed to complete one month of treatment due to toxicities. They were all from the higher thalidomide dose group. Toxicities included drowsiness (eleven patients), constipation (six patients), rash (four patients) and peripheral neuropathy (four patients). None of the patients have suffered a venous thromboembolic event. Fewer toxicities were noted in the lower dose thalidomide group.

CONCLUSION: The combination of thalidomide and dexamethasone is safe and effective in the treatment of newly diagnosed multiple myeloma. There is less toxicity and no loss of efficacy with lower doses of thalidomide.