Primary therapy with single agent bortezomib as induction, maintenance and re-induction in patients with high-risk myeloma: results of the ECOG E2A02 trial

Single agent bortezomib results in response rates of 51% in patients with newly diagnosed multiple myeloma and is touted to be especially effective in high-risk disease. We are the first to prospectively explore single agent bortezomib as primary therapy (induction, maintenance and re-induction) without consolidative autologous stem cell transplant in a cohort selected to have high-risk multiple myeloma. Patients received eight cycles of induction, followed by maintenance bortezomib every other week, indefinitely. Patients relapsing on maintenance had the full induction schedule resumed. On an intention-to-treat basis, the response rate (>= partial response) was 48%. Among seven patients who progressed on maintenance bortezomib and received re-induction, two responded to the treatment. With a median follow-up of 48.2 months, 1- and 2-year overall survival probabilities were 88% (95% confidence interval (CI) 79-98%) and 76% (95% CI 60-86%), respectively. Median progression-free survival was 7.9 months (95% CI 5.8-12.0). Twenty-three and thirty-four patients had >= grade 3 hematological and non-hematological toxicity, respectively, with treatment-emergent neuropathy in 7% with motor grade 1-2, 56% with sensory grade 1-2 and 2% with grade 3, and in 14% with neuropathic pain grade 1-2 and 2% with grade 3. In high-risk patients, upfront bortezomib results in response rates that are comparable to those reported for unselected cohorts, but single agent bortezomib is not sufficient as primary therapy. Leukemia (2010) 24, 1406-1411; doi:10.1038/leu.2010.129; published online 10 June 2010