Table 2.

Selected studies/assays utilized for MRD assessment in HCL.

Assay	Study reference	Patient N	Disease status	Disease status	Summary
IHC	Tallman et al. [24]	66	Frontline	Cladribine or pentostatin	4-year relapse-free survival superior in uMRD (88% vs. 55%; p = 0.0023
MFC	Chihara et al. [29]	59 14	Frontline and Relapsed	Cladribine followed by rituximab	No association of MRD with risk of relapse as few relapses
MFC	Chihara et al. [17]	68	Frontline	concomitant or delayed rituximab (after 6 months)	At 6 months uMRD higher in concomitant (97% vs. 24%; p < 0.0001) At 96 months median follow-up lower rate and durability of uMRD CR for delayed rituximab
MFC	Kreitman et al. [31]	33	Relapsed	Moxetumomab Pasudotox	Longer CR duration in patients with uMRD (Median 42.1 months vs. 13.5 months; p < 0.001)
MFC	Kreitman et al. [33]	80	Relapsed	Moxetumomab Paseudotox	Longer CR duration (62.8 vs. 12.0 months) in patients achieving uMRD
PCR for mutant BRAF	Tiacci et al. [14]	30	Relapsed	Vemurafenib plus rituximab	Higher relapse-free survival in patients with uMRD CR (100% VS. 56% at median 34 months follow-up
PCR for consensus IGH primer(cpPCR)	Sausville et al. [38]	24	Relapsed	various	MFC is superior to cpPCR for detecting MRD in HCL
PCR for clone-specific IGH primer (csPCR)	Aarons et al. [35]	10	Relapsed	BL22	csPCR was more sensitive than cpPCR and MFC for detecting MRD
ddPCR for mutant BRAF	Broccoli et al. [42]	36	Frontline and Relapsed	Cladribine	ddPCR is a sensitive assay for quantitation of disease burden and detection of MRD in morphological CR