Thalidomide and Dexamethasone in Newly Diagnosed Multiple Myeloma.

PURPOSE: The combination of 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 single-centre retrospective study evaluates the activity of the combination of thalidomide and dexamethasone in patients with newly diagnosed multiple myeloma attending the haematology department of the Mater Misericordiae University Hospital, Dublin.

METHODS: Forty-six patients with newly diagnosed multiple myeloma between April 2000 and April 2006 were treated with thalidomide and dexamethasone as first line treatment. The median age of the patients was 70 years (range 46 to 88 years). The median serum paraprotein level was 32g/l (range 2 to 99g/l). The median bone marrow plasma cell percentage was 40% (range 10% to 99%) The first twenty-two 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 twenty-four patients were commenced on thalidomide at 100mg od with the dose increased to a maximum of 200mg if tolerated. All patients received dexamethasone 40mg per day on days 1–4, 9–12 and 17–20 ot the first cycle and for a four day pulse every four weeks for subsequent cycles.

RESULTS: The response rate was 67.4% when assessed by Blade criteria (50% reduction in serum myeloma protein and 90% reduction of urine myeloma protein on at least two occasions for a minimum of 6 weeks). A complete response was observed in 10.9% of patients. There was no significant difference in response rates between the higher thalidomide dose group and the lower thalidomide dose group. The main toxicities included constipation in 57.8%, hyperglycaemia in 33.3%, peripheral neuropathy in 22.2%, drowsiness in 15.6%, peripheral oedema in 15.6%, venous thromboembolism in 11.1%, rash in 11.1% and proximal myopathy in 8.9%. Routine anticoagulation was not used although patients with additional risk factors for venous thromboembolism received prophylactic dose low molecular weight heparin and in total 53.3% of patients were receiving either aspirin, warfarin or low molecular weight heparin at the time of treatment. There was no significant difference between the two thalidomide dose groups in terms of frequency of toxicities. However 27.3% of patients in the higher thalidomide dose group had their treatment stopped within one month due to toxicities compared to 4.2% in the lower dose group.

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