Table 2 Recommended nomenclature for reporting measurable residual disease in CLL.
Recommended | Rationale |
|---|---|
Measurable residual disease (MRD) | Replaces “minimal” residual disease as a more objective term |
Undetectable-MRD (U-MRD) | As a general term, replaces MRD negative or MRD- as a more accurate term in cases where MRD threshold is not specified |
MRD4, MRD5, etc. | Specifies upper limit of disease (e.g., MRD4 denotes <0.01%/<10-4 disease, MRD5 < 0.001%/<10−5 disease, etc) for an individual sample or for a group of patients in clinical trial reporting |
Detectable (d) or undetectable (u) within an MRD category | Detectable = residual disease is below the stated threshold but measurable above the next MRD threshold. Undetectable = residual disease is not detectable, but the assay/sample is not suitable for detection of disease at the next threshold MRD4d: < 0.01%/10−4 but ≥0.001%/10−5 MRD4u: < 0.01%, assay limit of detection does not reach 0.001%/10−5 |
Always report assay method (e.g., Flow) and analysis technique (e.g., ERIC-FC) | Results may differ by assay method even for assays with identical sensitivity |
Always report tissue assayed (e.g., PB, BM) | MRD may differ in different tissues from the same patient/timepoint |
In clinical trials, always report MRD rate as percentage U-MRD in ITT population | Avoids confusion with the rate in the MRD-tested population, e.g., MRD4 rate = number of patients with <0.01% MRD as a percentage of the ITT population |
