Isatuximab-lenalidomide-bortezomib and low-dose dexamethasone: an effective steroid sparing regimen for transplant-ineligible MM

The phase II REST study is evaluating a steroid-sparing regimen consisting of isatuximab, lenalidomide, bortezomib and a limited dose of dexamethasone (Isa-VRd) as a first line treatment for transplant ineligible patients with newly diagnosed multiple myeloma (NDMM). The 51 patients in this study were treated with Isatuximab at a dose of 10 mg/kg IV on Days 1, 8, 15 and 22 during cycle 1 and q2w in cycles 2-18; bortezomib at a dose of 1.3 mg/m² SC on days 1, 8 and 15 during cycles 1-8; lenalidomide at a dose of 25 mg PO on days 1-21 during all cycles and dexamethasone at a dose 20 mg PO on days 1, 8, 15 and 22 of the first two treatment cycles. This regimen induced an MRD-negative complete response in 37% of patients, with 82% of patients in the study obtaining a very good partial response or better. At 18 months, the progression-free survival rate was reported at 78%, with a corresponding overall survival rate of 88%. As such, these results support the use of this modified quadruplet regimen, omitting dexamethasone from cycle 3 onwards, in transplant ineligible NDMM patients.