Treatment with bortezomib rather than thalidomide in newly-diagnosed multiple myeloma leads to deeper response rates but no improvement in survival, an interim analysis of Melbourne patients has concluded.

Dr Adrian Chee, from Monash Haematology, and colleagues reviewed 59 patients treated with thalidomide-containing induction regimens from 2009, and 70 who received bortezomib-based regimens after its PBS listing in October 2012.

The baseline characteristics of the two groups, including cytogenetics, age, sex, performance status and eligibility for transplantation, were similar and the median follow-up period was 21 months.

Both regimens produced comparable overall response rates (81% with thalidomide and 86% with bortezomib), but the rate of ‘very good partial response’ was significantly higher with bortezomib (49% compared to 20% with thalidomide).

“However, analyses to date have shown no significant difference in progression-free survival or overall survival,” Dr Chee said.

Rates of grade 1 and 2 neuropathy were similar, at about 33%, but two thalidomide patients had severe neuropathy requiring cessation of treatment.

“The lower rate of severe neuropathy with bortezomib may have reflected a shift from intravenous to subcutaneous weekly dosing,” he said.

“In the past decade the introduction of immunomodulatory drugs and proteasome inhibitors has significantly improved remission rates and survival outcomes in patients with multiple myeloma, leading to these agents becoming the standard of care in both primary and relapsed disease.

“The introduction of the proteasome inhibitor bortezomib has led to significant improvements in survival.”

Outcomes in the Melbourne patients will be continue to be analysed to determine whether any survival advantage emerges over time.