Lenalidomide, Bortezomib, and Dexamethasone (Rev/Vel/Dex) as Front-Line Therapy for Patients with Multiple Myeloma (MM): Preliminary Results of a Phase 1/2 Study.

Background: Bortezomib (VELCADE®, Vel) as a single agent and lenalidomide (Revlimid®, Rev) plus dexamethasone (Dex) are approved for the treatment of relapsed MM patients (pts) following ≥1 prior therapy. Rev/Vel±Dex is active and well tolerated in relapsed/refractory MM, and Rev/Dex and Vel/Dex have substantial activity in front-line MM. The aims of this phase 1/2 study were to determine the MTD of Rev/Vel/Dex in newly diagnosed MM pts, and to assess safety and efficacy.

Methods: Pts received Rev 15–25 mg on d 1–14, Vel 1.0–1.3 mg/m² on d 1, 4, 8, 11, and Dex 40/20 mg (cycles 1–4/5–8) on d 1, 2, 4, 5, 8, 9, 11, 12, for up to 8 21-d cycles, initially at 4 planned dose levels (Rev/Vel: 15/1.0, 15/1.3, 20/1.3, 25/1.3). Dose escalation proceeded (3-pt cohorts) depending on DLTs (G≥3 non-hematologic toxicity; G4 thrombocytopenia with platelets <10,000/mm³ on >1 occasion despite transfusion support; G4 neutropenia for >5 d and/or resulting in neutropenic fever; inability to receive cycle 2/d 1 dose due to drug-related toxicity). Based on safety data, dose level 4M was added with a reduced Dex starting dose (Rev/Vel 25/1.3, Dex 20 mg in all cycles). Toxicities were graded by NCI CTCAE v3.0. Pts with G>2 peripheral neuropathy (PNY) were excluded. Responses were assessed by modified EBMT and Uniform criteria. Pts with CR/nCR/VGPR/PR could proceed to ASCT after ≥4 cycles.

Results: 33 pts (median age 56 yrs, 55% men, 84% IgG MM, 47% with ISS Stage II/III) have been enrolled to date in dose levels 1–4 and 4M, respectively, including 10 pts enrolled at the maximum planned dose (Dose Level 4M). Pts have received a median of 5 cycles; 9 pts have completed all 8 cycles. Two DLTs of G3 hyperglycemia due to high dose Dex were seen in dose level 4. Dose reductions in cycle 2 and beyond have occurred in dose levels 1–4 for Rev in 9 pts, Vel in 7 pts, and Dex in 17 pts, with 3 dose reductions having occurred in dose level 4M. Toxicities to date have been manageable. Only 1 G4 toxicity (thrombocytopenia) has been reported, plus 1 G3 DVT (reversed with LMWH), and no G≥3 PNY has been seen. The response rate across all dose cohorts (CR/nCR+VGPR+PR: subject to confirmation) is currently 89% in 25/28 evaluable pts, including 35% CR/nCR/VGPR. After median follow-up of 3 mos, median DOR, TTP, PFS, and OS have not been reached; all responders except 1 remain in remission, with 2 pts proceeding to ASCT.

Conclusions: Rev/Vel/Dex is very active and well tolerated in newly diagnosed MM pts. The maximum planned dose has been reached at Rev 25 mg, Vel 1.3 mg/m², and Dex 20 mg, with Phase 1 enrollment now complete using the lower dose of Dex. Enrollment to the Phase 2 component is ongoing.