Delphi Survey on Measurable Residual Disease in Multiple Myeloma: Prevailing Practices and the Way Forward in India.

Background: Measurable residual disease (MRD) is becoming a cornerstone in the multiple myeloma (MM) management; however, its implementation in India faces several challenges. This Delphi survey aimed to gather expert consensus on the current practices, and barriers in MRD monitoring in MM in India.

Methods: A 3-round Delphi process (2 e-surveys and 1 in-person meeting) was conducted with hematologists, pathologists, and oncologists managing MM in India. Consensus (≥ 75% agreement) led to recommendations for standardized MRD practices.

Results: Twenty-five experts participated, agreeing on key protocols: processing first-pull bone marrow aspirates within 24 hours, using a single tube with at least a 10-color panel, acquiring at least 3 million events for 10⁻⁵ sensitivity under proper environmental control, and by adequately trained staff. At least 4 monoclonal antibodies for gating of plasma cells and at least 3 parameters among mast cells, myeloid precursors, hematogones, normal plasma cells, should be used to assess hemodilution. Guidance on modulation of treatment decisions, including maintenance therapy based on MRD status remains inconclusive. Though, there is an agreement that MRD negativity in MM improves survival and lowers relapse risk but currently it does not influence maintenance therapy decisions. MRD testing was advised at postinduction, pre/post-transplant, and annually during maintenance. Challenges identified included protocol variability, interpretation issues, and lack of an external quality assessment program. Experts emphasized the need for advanced flow cytometry training.

Conclusions: The findings of this study will guide clinical adoption and future research, particularly for high-risk populations and novel therapies.