BACKGROUND: Bortezomib, a first-in-class proteasome inhibitor, has shown 
clinical activity in relapsed, refractory multiple myeloma in a pivotal Phase II 
trial, SUMMIT.
METHODS: Patients received bortezomib 1.3 mg/m(2) on Days 1, 4, 8, and 11 
followed by a 10-day rest period for up to 8 cycles. Dexamethasone 20 mg on the 
day of and the day after bortezomib was permitted for suboptimal response. 
Extended treatment beyond 8 cycles was offered to patients whose physicians felt 
they would benefit from additional therapy. Follow-up was conducted in all 
patients for a median of 23 months, an additional 13 months from the original 
report.
RESULTS: Of 202 patients enrolled in SUMMIT, 193 were evaluable for response. 
Seven (4%) patients achieved a complete response, 12 (6%) achieved a nearly 
complete response, 34 (18%) achieved a partial response, and 14 (7%) had a 
minimal response while on bortezomib. The updated median duration of response to 
bortezomib alone was 12.7 months. The median overall time to progression for all 
SUMMIT patients was 7 months. For responding patients, the median time to 
progression was 13.9 months, whereas for those with progressive disease (PD) or 
who were not evaluable, the median time to progression was 1.3 months. The 
median overall survival (OS) for all SUMMIT patients was 17.0 months. Whereas 
the median OS for patients with PD or who were not evaluable was 8 months, the 
median OS for responding patients was not reached at 23 months of follow-up.
CONCLUSIONS: These data demonstrate that treatment with bortezomib results in 
meaningful long-term benefit for patients with relapsed and refractory myeloma.