Several new regimens with bortezomib (Velcade) are currently being investigated in combination with different agents for various subpopulations of patients with multiple myeloma or were presented at ASCO 2011.
Bortezomib and Dexamethasone
Bortezomib is currently approved for the treatment of multiple myeloma. Because twice-weekly bortezomib is associated with toxicity such as neuropathy, some studies are investigating new regimens with only once-weekly administration of the drug.
In one study in which patients received a once-weekly regimen of bortezomib for 4 weeks, oral dexamethasone (Decadron) was taken on the day of and the day after receiving bortezomib, for 6 cycles. Among all the patients who have received at least 1 cycle of bortezomib, 64% have achieved a partial response or better, with 15% of them achieving a complete or near-complete response.
An intent-to-treat analysis showed an objective response rate of 78% in 41 patients. Only 1 patient has developed grade 3 neuropathy.
Bortezomib plus Bendamustine
Another trial was an open-label phase 1 study that assessed bortezomib in combination with bendamustine (Treanda) in a heavily pretreated population of patients with relapsed or refractory multiple myeloma.
Results showed that the combination was well tolerated, and the objective response rate was nearly 50%, including an approximately 40% response rate in patients who previously received bortezomib, and a clinical benefit rate (responses plus stable disease) of more than 90%.
Other Regimens Under Way
The use of bortezomib in combination with oral panobinostat and dexamethasone is under study in a phase 3 trial of 672 patients with relapsed/refractory multiple myeloma. Results are pending.
A new regimen of pegylated liposomal doxorubicin, bortezomib, dexamethasone, and lenalidomide (Revlimid) is under investigation in 40 patients with relapsed/refractory multiple myeloma. Interim data from 27 patients show objective responses in 70% of patients, including a 19% complete response rate.
To date, 1 of these patients has experienced grade 4 reversible thrombocytopenia and 8 patients have developed peripheral neuropathy.