While upfront autologous transplantation has bested bortezomib-based intensification therapy in a large, randomized multiple myeloma (MM) trial, investigators and observers say more research will be needed to determine the optimal treatment strategy in the era of novel agents.
Autologous hematopoietic stem cell transplantation (HSCT) extended progression-free survival by almost 15 months compared with bortezomib, melphalan, and prednisone (VMP) intensification therapy for the treatment of newly diagnosed multiple myeloma, according to results of the randomized, phase 3 trial of 1,503 patients enrolled at 172 centers in the European Myeloma Network.
That finding could provide more fodder for the ongoing debate over the role of upfront autologous HSCT as a gold-standard intensification treatment for patients who can tolerate myeloablative doses of chemotherapy in light of the proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies that are now available.
However, the study is not without limitations, including the use of bortezomib, cyclophosphamide, and dexamethasone (VCD) as induction therapy, according to the investigators, led by Michele Cavo, MD, with the Seràgnoli Institute of Hematology at Bologna (Italy) University.
The VCD regimen was one of the most frequently used induction regimens back when the trial was designed, but now it's considered "less optimal" versus regimens such as bortezomib, lenalidomide, and dexamethasone (VRD), according to Dr. Cavo and coinvestigators.
Besides, the field is moving forward based on clinical trials of "highly active" daratumumab-based four-drug regimens, which appear to enhance rates of response and minimal residual disease (MRD) negativity when given as induction before autologous HSCT and as consolidation afterward, they said.
"Final results from these studies should be awaited before a shift from routine use of upfront autologous HSCT to delayed HSCT or alternative treatment strategies driven by MRD status can be offered to patients with newly diagnosed multiple myeloma who are fit for high-dose chemotherapy," Dr. Cavo and colleagues noted in their report, available in The Lancet Hematology.
The multicenter, randomized, open-label, phase 3 study by Dr. Cavo and coinvestigators, known as EMN02/HO95, included patients up to 65 years of age with symptomatic multiple myeloma, measurable disease, and WHO performance of 0 to 2. Patients were treated with VCD induction therapy, followed by randomization to either VMP or autologous HSCT after high-dose melphalan. In a second randomization, patients were assigned to either VRD consolidation therapy or no consolidation. All patients then received lenalidomide maintenance therapy until progression.
Median progression-free survival was 56.7 months in patients initially randomized to HSCT, compared with 41.9 months for MP (hazard ratio, 0.73; 95% confidence interval, 0.62-0.85; P = .0001), according to the investigators, who said that finding supports the value of HSCT "even in the era of highly active novel agents."
Turning to results of the second randomization, Dr. Cavo and colleagues said the VRD consolidation strategy resulted in median progression-free survival that was significantly improved versus no consolidation, at 58.9 months and 45.5 months, respectively (P = .014).
While this is an important study, the added benefit of HSCT intensification therapy is in question given the high rates of MRD being reported for potent, daratumumab-based four-drug combination regimens, according to a related commentary by Omar Nadeem, MD, and Irene M. Ghobrial, MD, of Dana-Farber Cancer Institute and Harvard Medical School, Boston.
"We are entering an era in which novel combinations have shown unprecedented efficacy and future studies with or without HSCT will be needed to answer these key questions," wrote Dr. Nadeem and Dr. Ghobrial.
Dr. Cavo and colleagues said the estimated 5-year rate of overall survival in EMN02/HO95 was "comparable" between arms, at 75% for the HSCT strategy and 72% for VMP.
"Although this suggests that delaying HSCT to a later time is not harmful, a substantial proportion of patients may become ineligible for high-dose melphalan at first relapse," they said, noting that 63% of VMP-treated patients went on to receive salvage HSCT.
Further follow-up could demonstrate a survival advantage, as seen in other studies, they added.
Dr. Cavo reported that he has received honoraria from multiple pharmaceutical companies, and is a member of speakers bureaus for Janssen and Celgene. Dr. Nadeem and Dr. Ghobrial reported serving on the advisory boards of multiple pharmaceutical companies.
SOURCE: Cavo M et al. Lancet Haematol. 2020 Apr 30. doi: 10.1016/S2352-3026(20)30099-5.
This story originally appeared on MDedge.com.