Outcomes of younger patients with mantle cell lymphoma experiencing late relapse (>24 months): the LATE-POD study

• Patients with MCL experiencing late relapse benefit from BTK-inhibitors over chemoimmunotherapies.

• Overall, chemoimmunotherapies as second-line treatment are discouraged in the era of chimeric antigen receptor T-cell therapies.

Patients with mantle cell lymphoma (MCL) who experience first relapse/refractoriness can be categorized into early or late progression-of-disease (POD) groups, with a threshold of 24 months from MCL diagnosis. Bruton tyrosine kinase inhibitors (BTKi) are the established standard treatment at first relapse, but their effectiveness compared with chemoimmunotherapy (CIT) in late-POD patients remains unknown. In this international, observational cohort study, we evaluated outcomes among patients at first, late POD beyond 24 months. The primary objective was progression-free survival from the time of second-line therapy (PFS-2) of BTKi vs CIT. Overall, 385 late-POD patients were included from 10 countries. Their median age was 59 years (range, 19-70), and 77% were male. Median follow-up from the time of second-line therapy was 53 months (range, 12-144). Overall, 114 patients had second-line BTKi, whereas 271 had CIT, consisting of rituximab-bendamustine (R-B; n = 101), R-B and cytarabine (R-BAC; n = 70), or other regimens (mostly cyclophosphamide-hydroxydaunorubicin-vincristine-prednisone]- or platinum-based; n = 100). The 2 groups were balanced in clinicopathological features and median time to first relapse. Overall, BTKi was associated with significantly prolonged median PFS-2 than CIT (not reached [NR] vs 26 months, respectively; P = .0003) and overall survival (NR and 56 months, respectively; P = .03). Multivariate analyses showed that BTKi was associated with lower risk of death than R-B and other regimens (hazard ratio, 0.41 for R-B and 0.46 for others), but similar to R-BAC. These results may establish BTKi as the preferable second-line approach in patients with BTKi-naïve MCL.