Summary of the 2019 Blood and Marrow Transplant Clinical Trials Network Myeloma Intergroup Workshop on Minimal Residual Disease and Immune Profiling

Association of Minimal Residual Disease Negativity Rates With Progression Free Survival in Frontline Therapy Trials for Newly Diagnosed Multiple Myeloma: A Meta-analysis

Current frontline therapies for newly diagnosed multiple myeloma patients have significantly prolonged progression-free survival (PFS). This has led to interest in minimal residual disease negativity (MRDng) as an efficacy-response biomarker and possible surrogate endpoint. A meta-analysis was conducted to explore the surrogacy of MRD for PFS and quantify the relationship between MRDng rates and PFS at the trial level. A systematic search was conducted on phase II and III trials reporting MRDng rates along with median PFS (mPFS) or PFS hazard ratios (HR). Weighted linear regressions were conducted relating mPFS to MRDng rates, and relating PFS HRs to either odds ratios (OR) or rate differences (RD) for MRDng in comparative trials. A total of 14 trials were available for the mPFS analysis. log(MRDng rate) was moderately associated with log (mPFS), with a slope of β = 0.37 (95% CI, 0.26-0.48) and R² = 0.62. A total of 13 trials were available for the PFS HR analysis. Treatment effects on MRDng rates were correlated with the corresponding effects on PFS: log (PFS HR) and log (MRDng OR) had a moderate association with β = -0.36 (95% CI, -0.56 to -0.17) and R² = 0.53 (95% CI, 0.21-0.77); log (PFS HR) and the MRDng RD had a stronger association with slope β = -0.03 (95% CI, -0.04 to -0.02) and R² = 0.67 (95% CI, 0.31 to 0.86). MRDng rates moderately associate with PFS outcomes. MRDng RDs are more strongly associated with HRs than MRDng ORs, with evidence suggestive of potential surrogacy.

MRD dynamics during maintenance for improved prognostication of 1280 patients with myeloma in the TOURMALINE-MM3 and -MM4 trials

Measurable residual disease (MRD) evaluation may help to guide treatment duration in multiple myeloma (MM). Paradoxically, limited longitudinal data exist on MRD during maintenance. We investigated the prognostic value of MRD dynamics in 1280 transplant-eligible and -ineligible patients from the TOURMALINE-MM3 and -MM4 randomized placebo-controlled phase 3 studies of 2-year ixazomib maintenance. MRD status at randomization showed independent prognostic value (median progression-free survival [PFS], 38.6 vs 15.6 months in MRD- vs MRD+ patients; HR, 0.47). However, MRD dynamics during maintenance provided more detailed risk stratification. A 14-month landmark analysis showed prolonged PFS in patients converting from MRD+ to MRD- status vs those with persistent MRD+ status (76.8% vs 27.6% 2-year PFS rates). Prolonged PFS was observed in patients with sustained MRD- status vs those converting from MRD- to MRD+ status (75.0% vs 34.2% 2-year PFS rates). Similar results were observed at a 28-month landmark analysis. Ixazomib maintenance vs placebo improved PFS in patients who were MRD+ at randomization (median, 18.8 vs 11.6 months; HR, 0.65) or at the 14-month landmark (median, 16.8 vs 10.6 months; HR, 0.65); no difference was observed in patients who were MRD-. This is the largest MM population undergoing yearly MRD evaluation during maintenance reported to date. We demonstrate the limited prognostic value of a single-time point MRD evaluation, because MRD dynamics over time substantially impact PFS risk. These findings support MRD- status as a relevant end point during maintenance and confirm the increased progression risk in patients converting to MRD+ from MRD- status. These trials were registered at www.clinicaltrials.gov as #NCT02181413 and #NCT02312258.

Proceedings from the Blood and Marrow Transplant Clinical Trials Network Myeloma Intergroup Workshop on Immune and Cellular Therapy in Multiple Myeloma

The Blood and Marrow Transplant Clinical Trials Network (BMT CTN) Myeloma Intergroup conducted a workshop on Immune and Cellular Therapy in Multiple Myeloma on January 7, 2022. This workshop included presentations by basic, translational, and clinical researchers with expertise in plasma cell dyscrasias. Four main topics were discussed: platforms for myeloma disease evaluation, insights into pathophysiology, therapeutic target and resistance mechanisms, and cellular therapy for multiple myeloma. Here we provide a comprehensive summary of these workshop presentations.

The 2020 BMT CTN Myeloma Intergroup Workshop on Immune Profiling and Minimal Residual Disease Testing in Multiple Myeloma

The fifth annual Blood and Marrow Transplant Clinical Trials Network Myeloma Intergroup Workshop on Immune Profiling and Minimal Residual Disease Testing in Multiple Myeloma was conducted as one of the American Society of Hematology Annual Meeting Scientific Workshops on Thursday December 3, 2020. This workshop focused on four main topics: (1) integrating minimal residual disease into clinical trial design and practice; (2) the molecular and immunobiology of disease evolution and progression in myeloma; (3) adaptation of next-generation sequencing, next-generation flow cytometry, and cytometry by time of flight techniques; and (4) chimeric antigen receptor T-cell and other cellular therapies for myeloma. In this report, we provide a summary of the workshop presentations and discuss future directions in the field.

Future Directions in Maintenance Therapy in Multiple Myeloma

Autologous stem cell transplantation (ASCT) has been a backbone of therapy for newly diagnosed patients with multiple myeloma eligible for high-dose therapy for decades. Survival outcomes have continued to improve over time, in part because of the incorporation of highly effective induction regimens prior to ASCT as well as post-ASCT maintenance therapy. Randomized phase III clinical trials have helped establish lenalidomide maintenance as a standard of care. However, as nearly all patients will eventually experience disease relapse, there continues to be significant interest in developing novel maintenance strategies to improve upon lenalidomide maintenance. In this review, we summarize the available evidence for the use of immunomodulatory drugs, proteasome inhibitors, and monoclonal antibodies as post-ASCT maintenance therapies as well as discuss future directions and unanswered questions in the field.