Extended follow-up of a phase II trial in relapsed, refractory multiple myeloma:: final time-to-event results from the SUMMIT trial.
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.
Department of Medical Oncology/Hematologic Malignancies, Dana-Farber Cancer Institute, Brigham and Women's Hospital, 44 Binney Street, Boston, MA 02115, USA. Paul_Richardson@dfci.harvard.edu
Paul G
PG
Richardson
Bart
B
Barlogie
James
J
Berenson
Seema
S
Singhal
Sundar
S
Jagannath
David H
DH
Irwin
S Vincent
SV
Rajkumar
Gordan
G
Srkalovic
Melissa
M
Alsina
Kenneth C
KC
Anderson
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001897:Boronic Acids / Q000627:therapeutic use*; D000069286:Bortezomib; D003907:Dexamethasone / Q000627:therapeutic use; D004338:Drug Combinations; D019008:Drug Resistance, Neoplasm; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000188:drug therapy*; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy*; D011719:Pyrazines / Q000627:therapeutic use*; D016879:Salvage Therapy; D013997:Time Factors; D016896:Treatment Outcome
D000893:Anti-Inflammatory Agents; D000970:Antineoplastic Agents; D001897:Boronic Acids; D004338:Drug Combinations; D011719:Pyrazines; D000069286:Bortezomib; D003907:Dexamethasone