Clinical yield of laboratory monitoring during ritlecitinib treatment for alopecia areata

BACKGROUNDRoutine laboratory monitoring is recommended during Janus kinase inhibitor therapy, but its clinical yield in patients with alopecia areata has not been prospectively characterized.

OBJECTIVETo characterize the incidence, timing, severity, and clinical significance of laboratory abnormalities during ritlecitinib treatment.

METHODSIn this prospective cohort, patients aged 12 years or older received ritlecitinib 50 mg once daily. Complete blood count, liver, and renal function parameters were assessed. Treatment-emergent abnormalities were predefined using local reference intervals and graded using Common Terminology Criteria for Adverse Events 5.0. Exploratory Cox regression was performed to identify factors associated with first laboratory abnormality.

RESULTSAmong 162 patients contributing 62.9 patient-years, 99 (61.1%) developed at least 1 treatment-emergent laboratory abnormality; 67 first events (67.7%) occurred within 3 months. Abnormalities were predominantly mild: 97 patients had maximum grade 1 abnormalities, 2 had grade 2 abnormalities, and none had grade 3 or higher abnormalities. Prior systemic treatment was associated with higher hazard on univariable analysis (hazard ratio, 1.52; 95% confidence interval, 1.02-2.28; P = .041), but no independent predictor remained after multivariable adjustment.

LIMITATIONSSingle-center design, Chinese cohort, and incomplete scheduled monitoring.

CONCLUSIONLaboratory abnormalities during ritlecitinib therapy were common but mild and rarely actionable, supporting potential reconsideration of monitoring intensity.

Abstract from PubMed