An observational, retrospective analysis of retreatment with bortezomib for multiple myeloma.

PURPOSE

The aim of this retrospective chart review of patients with multiple myeloma (MM) was to describe patterns of retreatment with bortezomib-based therapy and responses to retreatment in a community-based setting.

PATIENTS AND METHODS

Data were retrospectively extracted from the medical records of patients treated in US Oncology-affiliated community oncology clinics who received 2 separate treatments with bortezomib-based therapy. Eligible patients had > or = 60 days between treatments and > or = 4 bortezomib doses during initial treatment. Responses were determined primarily by laboratory values. Response categories included (1) very good partial response (VGPR), > or = 90% M-protein decrease; (2) partial response (PR), 50%-89% decrease; and (3) less than PR (< PR), < 50% decrease, excluding progressive disease (PD).

RESULTS

Retreatment response data were available for 82 patients; 5 (6%) had VGPR, 12 (15%) had PR, 52 (63%) had < PR, 5 (6%) had PD, and 8 (10%) died. Among 62 patients with response assessments for initial treatment and retreatment, VGPR/PR rates to retreatment were 44%, 23%, and 13% among patients with VGPR, PR, and < PR to initial treatment, respectively. Median time between bortezomib treatments was 9.7 months; 29% of patients received non-bortezomib therapy between treatments. The most common treatment pattern (58% of patients) was single-agent bortezomib at initial treatment and retreatment. Toxicity contributed to discontinuation in 38% of patients during initial treatment and 22% during retreatment; rates of neuropathy contributing to discontinuation were 18% and 6%, respectively.

CONCLUSION

Retreatment with bortezomib-based therapy is feasible, with predictable toxicities. This observational analysis supports bortezomib alone or in combination as a retreatment option after initial bortezomib treatment in patients with relapsed MM.