Promising new drugs are being evaluated for treatment of multiple myeloma (MM), but their impact should be measured against the expected outcome in patients failing current therapies. However, the natural history of relapsed disease in the current era remains unclear. We studied 286 patients with relapsed MM, who were refractory to bortezomib and were relapsed, refractory, or ineligible, to an IMiD (Immunomodulatory Drug), with measurable disease and ECOG PS of 0, 1 or 2. The date patients satisfied the entry criteria was defined as time zero (T0). The median age at diagnosis was 58 years and time from diagnosis to T0 was 3.3 years. Following T0, 213 (74%) patients had a treatment recorded with one or more regimens (median=1; range 0-8). The first regimen contained bortezomib in 55 (26%) patients and an IMiD in 70 (33%). A minor response or better was seen to at least one therapy after T0 in 94 patients (51%) including >=partial response in 69 (38%). The median overall survival and event free survival from T0 were 9 and 5 months respectively. This study confirms the poor outcome once patients become refractory to current treatments. The results provide context for interpreting ongoing trials of new drugs.

Background: A phase II trial evaluating the response rate with sequential administration of Bortezomib, cyclophosphamide, and dexamethasone (3 cycles) followed by Bortezomib, Thalidomide, and dexamethasone (3 cycles). The primary endpoints are overall response, achievement of ≥ very good partial response (VGPR), as well as assessment of safety and tolerability. This report provides results for 25 of 43 planned eligible pts. Methods: Pts with newly diagnosed, untreated symptomatic myeloma were eligible. Treatment consisted of three 21-day cycles of Bortezomib 1.3mg/m2 days 1, 4, 8, and 11, Cyclophosphamide 300mg/m2 IV days 1 and 8 and dexamethasone 40mg po or IV days 1, 2, 4, 5, 8, 9, 11, 12; followed by three 21-day cycles of Bortezomib 1.0 mg/m2 days 1, 4, 8, and 11; Thalidomide 100 mg po daily and dexamethasone as before. Pts received thrombosis prophylaxis with ASA cycles 4–6. Upon completion of the 6 courses, pts proceeded to stem cell harvest and/or maintenance therapy. Responses were assessed by International Response Criteria. Results: As of August 2007, 25 pts have been enrolled: median age 60 years; 65% male; 75% Stage III (D/S); IgG 66%, IgA 16%; 17% light chain only. All pts fully evaluable for response thus far (13/13 [100%]) have achieved at least PR. Of these, 7/13 (54%) have achieved ≥VGPR (with nCR/CR in 31%). The median time to PR was 2 cycles or 42 days. Maximum response occurred by cycle 4 for 12/13 (92%)pts. Overall, both components of the sequential regimen were very well tolerated. One pt had a ruptured colonic diverticulum related to dexamethasone, but recovered well and achieved nCR on trial. There have been 24 therapy attributed toxicity events ≥Grade 2 of which 11 have required drug/schedule adjustments: 3 each for cyclophosphamide (neutropenia), dexamethasone (hyperglycemia, pneumonia, perforated viscus) and Thalidomide (neuro related) plus 2 for Bortezomib (neuropathy). No deep vein thromboses (DVT) have occurred in the study. 3 pts have already proceeded to successful stem cell harvest with transplant planned. Conclusion: The addition of cyclophosphamide and Thalidomide to Bortezomib/dexamethasone combination has improved the depth of response with ≥VGPR (54%) and CR/nCR (31%) compared to our previous 2-drug experience which produced ≥VGPR (38%). This very well tolerated new regimen is potentially an important step forward with further results and confirmation available by December 2007.

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