The striking activity of thalidomide (Thalomid) as a single agent in refractory multiple myeloma has been confirmed in 169 patients with ³ 25% paraprotein reduction (PPR) in 36%, PPR ³ 50% in 28%, PPR ³ 75% in 20%, and complete/near
The striking activity of thalidomide (Thalomid) as a single agent in refractory multiple myeloma has been confirmed in 169 patients with ³ 25% paraprotein reduction (PPR) in 36%, PPR ³ 50% in 28%, PPR ³ 75% in 20%, and complete/near-complete response in 12%; 25% PPR was apparent in > 80% of patients within 2 months. The PPR was accompanied by marked reduction/clearing of bone marrow plasmacytosis and improved/recovered hemoglobin levels dependent on the degree or PPR.
The median event-free survival was reached at 5 months, whereas at 18 months, overall survival is 55% and event-free survival is 30%. Bone marrow plasmacytosis > 30% and chromosome 13 deletion (del 13) had independent adverse effects on both event-free survival and overall survival. Fifty-four low-risk patients (no del 13, bone marrow plasmacytosis £ 30%) have a 77% overall survival at 18 months compared to 53% in 72 intermediate-risk patients and 20% in 33 high-risk patients (P = < .00001).
Toxicities (constipation, weakness, somnolence, tingling/numbness) were dose related so that 90% tolerated 400 mg of thalidomide. Durable PPR in refractory multiple myeloma without significant myelosuppression prompted several randomized chemotherapy trials with a thalidomide dose of 400 mg. Twenty patients with posttransplant relapse, bone marrow plasmacytosis £ 30%, and absence of del 13 were offered dexamethasone ± thalidomide. Fifty patients with high tumor mass or high-risk refractory multiple myeloma were randomized to DCEP (dexamethasone/cyclophosphamide [Cytoxan, Neosar]/etoposide/cisplatin [Platinol]) ± thalidomide.
A total of 110 patients with more than one cycle of prior therapy have received DT-PACE (thalidomide combined with DCEP plus doxorubicin [Adriamycin]) (Blood 92[10 suppl 1]:273b, 1998, abstract 4180). In the case of PPR ³ 50% after DT-PACE ´ 2, DT-PACE is either continued or patients are randomly assigned to two cycles of melphalan (Alkeran) at 200 mg/m² with peripheral blood stem-cell support. 125 newly diagnosed patients have started the Total Therapy II regimen with up-front randomization to thalidomide at 400 mg or not. After induction and melphalan ´ 2, patients are further randomized to two different intensities of consolidation therapies.
CONCLUSION: Results are pending. Depending on evaluations by the data monitoring and biostatistics committee, the results of these trials will be presented either according to thalidomide randomization or, in case randomization is to continue, for the entire trial groups, without disclosure of results by individual treatment arm.