NEW YORK – , though data from additional randomized trials are needed to define their role in clinical practice, according to Natalie S. Callander, MD, of the University of Wisconsin Carbone Cancer Center, Madison.
“The outlook for myeloma patients is quite good,” Dr. Callander said at the National Comprehensive Cancer Network Hematologic Malignancies Annual Congress.
“Triplet therapy is the standard, and quad therapy may be in the future.”
The study that set the standard for triplets in myeloma, according to Dr. Callander, is SWOG 0777, an open-label, phase 3 trial that compared bortezomib with lenalidomide and dexamethasone (VRd) to lenalidomide and dexamethasone alone in patients with newly diagnosed myeloma.
Adding bortezomib to lenalidomide and dexamethasone significantly improved both progression-free and overall survival in the 525-patient trial, with a risk-benefit profile that was acceptable (Lancet. 2017 Feb 4;389[10068]:519-27).
The median progression-free survival was 43 months for the triplet, versus 30 months for the two-drug regimen (P = .0018); likewise, median overall survival was significantly improved, at 75 months versus 64 months for triplet versus doublet therapy (P = .025).
“Very convincingly, just receiving that short exposure to bortezomib ended up causing a substantial increase of progression-free and overall survival,” Dr. Callander said.
The efficacy of multiple triplet regimens has been documented, including the combination of carfilzomib, lenalidomide, and dexamethasone (KRd); cyclophosphamide, bortezomib, and dexamethasone (CyBorD); and more recently, ixazomib, lenalidomide, and dexamethasone (IRd). These regimens have “excellent” response rates and survival data, Dr. Callander said.
Data is now emerging on the potential role of four-drug combinations, she added. The combination of elotuzumab plus VRd produced high response rates that were even higher after transplant, with reasonable toxicity, Dr. Callander said of phase 2 trial data presented at the 2017 annual meeting of the American Society of Clinical Oncology.
Similarly, the combination of daratumumab plus KRd had a 100% rate of partial response or better in phase 2 data presented at ASCO in 2017, with rates of very good partial response and complete response that improved with successive cycles of therapy, she said.
Even so, “it remains to be seen whether four drugs will be the new standard,” Dr. Callander told the NCCN attendees.
Four- versus three-drug strategies are being evaluated in ongoing randomized clinical trials, including patients with previously untreated myeloma, she said. Those studies include Cassiopeia, which is evaluating bortezomib, thalidomide, and dexamethasone (with or without daratumumab), and GRIFFIN, which is looking at VRd (with or without daratumumab).
Daratumumab recently received an additional indication in the treatment of myeloma, this time as part of a four-drug regimen, Dr. Callander added in a discussion on treatment options for elderly myeloma patients.
The Food and Drug Administration approved the monoclonal antibody in combination with bortezomib, melphalan, and prednisone (VMP) for treatment of newly diagnosed myeloma patients who are transplant ineligible.
That approval was based on results of the multicenter phase 3 ALCYONE study, showing an 18-month progression-free survival rate of 71.6% for the four-drug combination versus 50.2% for VMP alone (N Engl J Med. 2018;378:518-28).
Dr. Callander reported having no relevant financial disclosures.
