Table 1.

MRD in multiple myeloma

Validated points	Open issues
MRD negativity is a surrogate for PFS	Optimal threshold for PFS and/or OS prediction by NGS or NGF
MRD negativity is a surrogate for OS	Need for both NGS and NGF
MRD by NGS is standardized	Time interval to define sustained MRD negativity
MRD by NGF (Euroflow) is standardized	Definition of loss of MRD-negative status
MRD by NGS or NGF and PET-CT are complementary	Optimal timing for MRD assessment during and after treatment
MRD useful to compare treatment options	Meaning of MRD negativity in specific subgroups, i.e., high-risk cytogenetics
	Standardization of MRD by PET-CT
	Best tracer for PET-CT
	MRD to alter therapy: duration of maintenance, change treatment, add agents…
	Blood-based MRD assessment
	MRD and detection of clonal evolution
	MRD and MGUS-like profile
	MRD as a valid end-point for drug approval