Vorinostat Plus Bortezomib Active in Refractory Myeloma

The combination of vorinostat plus bortezomib is active in patients with multiple myeloma who are refractory to novel treatment strategies, a study published in the journal Clinical Lymphoma, Myeloma, & Leukemia has shown.¹ This regimen may potentially offer a new therapeutic option for this difficult-to-treat population.

For the multicenter, open-label, single-arm, phase 2b study, researchers sought to assess the efficacy and tolerability of vorinostat with bortezomib in patients who were refractory to novel multiple myeloma therapies.

Investigators enrolled adult patients who had received 2 or more prior regimens, including 1 prior bortezomib-containing regimen and at least 1 dose of regimen containing an immunomodulatory agent, such as thalidomide, lenalidomide, and pomalidomide.

All patients received bortezomib 1.3 mg/m² intravenously on days 1, 4, 8, and 11 plus vorinostat 400 mg/day orally on days 1 to 14 of each 21-day cycle. Participants with progressive disease after 2 cycles of no change after 4 cycles were eligible to receive dexamethasone 20 mg orally on day of and day after each bortezomib dose.

Results showed that the objective response rate was 11.3% (95% CI, 6.6 – 17.7) and the median duration of response was 211 days (range, 64 – 550).

Researchers found that median overall survival was 11.2 months (95% CI, 8.5 – 14.4) and 32% of patients were alive at 2 years.

In terms of safety, the most commonly reported adverse events associated with treatment were thrombocytopenia (69.7%), nausea (57.0%), diarrhea (53.5%), anemia (52.1%), and fatigue (48.6%). Investigators deemed the overall safety profile to be consistent with bortezomib and vorinostat.

Vorinostat is a histone deacetylase (HDAC) inhibitor indicated for the treatment of cutaneous manifestations in patients with cutaneous T-cell lymphoma. It is under investigation for the treatment of patients with multiple myeloma. Panobinostat was the first HDAC inhibitor approved by the U.S. Food and Drug Administration for multiple myeloma.

Reference

1. Siegel DS, Dimopoulos M, Jagannath S, et al. VANTAGE 095: An international, multicenter, open-label study of vorinostat (MK-0683) in combination with bortezomib in patients with relapsed and refractory multiple myeloma [published online ahead of print March 4, 2016]. Clin Lymphoma Myeloma Leuk. doi: 10.1016/j.clml.2016.02.042.