ABSTRACTObjectives We assessed real-world healthcare resource utilization (HRU) and costs among US patients with relapsed or refractory mantle cell lymphoma (R/R MCL) by line of therapy (LoT).Methods We selected patients from MarketScan® (1/1/2016–12/31/2020): ≥1 claims of MCL-indicated first line (1L) therapies, ≥1 diagnoses of MCL pre-index date (1L initiation date), ≥6-month continuous enrollment pre-index date, second line (2L) therapy initiation, ≥18 years old at 2L, and no clinical trial enrollment. Outcomes included time to next treatment (TTNT), all-cause HRU, and costs.Results The cohort (N = 142) was 77.5% male, aged 62 years (median). Sixty-six percent and 23% advanced to 3L and 4L+, respectively. Mean (median) TTNT was 9.7 (5.9), 9.3 (5.0), and 6.3 (4.2) months for 2L, 3L, and 4L+, respectively. Mean (median) per patient per month (PPPM) costs were $29,999 ($21,313), $29,352 ($20,033), and $30,633 ($23,662) for 2L, 3L, and 4L+, respectively. Among those who received Bruton tyrosine kinase inhibitors, mean (median) PPPM costs were $24,702 ($17,203), $31,801 ($20,363), and $36,710 ($25,899) for 2L, 3L, and 4L+, respectively.Conclusions During the period ending in 2020, patients relapsed frequently, incurring high HRU and costs across LoTs. More effective treatments with long-lasting remissions in R/R MCL may reduce healthcare burden.