Over-expression of Bcl-2 has been linked to acquired dex resistance in MM cells. Conversely, reduction of Bcl-2 using oblimersen has been shown to enhance dex-induced apoptosis in MM cell lines and in fresh MM cells in culture (

Liu et al.,
Blood
101
:
4105
,
2003
). Preliminary non-randomized clinical studies have suggested that oblimersen may potentiate the activity of VAD and dex/thalidomide in patients (pts) with resistant MM. We have conducted a randomized, multinational, Phase 3 trial of pts with advanced MM using dex given with or without oblimersen. Eligibility requirements included: relapsed or refractory MM; measurable M-protein in serum or urine; ≤ 6 prior regimens; ECOG PS ≤ 3; serum Cr ≤ 1.5 mg/dL; ANC > 1,000/ml; plts ≥ 50,000/ml. Exclusions: previous allogeneic transplant; other significant medical disease. Pts were stratified according to number of prior treatments (1 or 2 vs. ≥ 3 regimens), prior autologous stem cell transplant (yes/no), and primary resistance to vs. relapse from primary treatment. All pts received dex 40 mg p.o. x 4 days during weeks 1, 2 and 3. Pts randomized to oblimersen received 7 mg/kg/d x 7 days by IV infusion, beginning 3 days before dex treatment during the 1st and 3rd weeks, and during all subsequent dex cycles. Beginning on week 5, additional 4-day dex cycles were repeated in stable or responding pts every 3 weeks, for a maximum of 12 months. All pts received prophylactic H-2 antagonists, TMP/SMZ, and a bisphosphonate. Response assessments were conducted prior to each treatment cycle. The primary endpoint of the study was to compare time-to-disease progression between the 2 treatment groups. Secondary endpoint comparisons included overall survival, event-free survival at 6 months, overall response rates, response duration, clinical benefit, and safety. A total of 224 pts were randomized into the study. All pts have completed > 12 mos follow-up, and final results of this trial will be presented.

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