Outcomes for Recurrent Mantle Cell Lymphoma Post-Ibrutinib Therapy: A Retrospective Cohort Study from a Japanese Administrative Database

Introduction: Treatment options in patients with mantle cell lymphoma (MCL) failing ibrutinib are limited, with no standard therapies defined. This study aimed to investigate real-world treatment patterns and outcomes for patients with MCL following ibrutinib.

Methods: This study utilized a de-identified hospital-based claims database (Medical Data Vision) in Japan. Eligible patients were adults who were diagnosed with MCL and had received antitumor drugs between December 2010 and July 2020. Patients were followed from the first antitumor drug treatment until the end of available data up to July 2021. Time-to-event analyses utilized the Kaplan-Meier method. Factors for receiving post-ibrutinib therapy were explored with logistic regression analysis.

Results: Of the 1386 patients who started antitumor drug therapy, 247 patients received and discontinued ibrutinib at any line of therapy. Among them, 137 patients (55.5%) received subsequent therapy. The median age at the end of ibrutinib therapy was 77 (range 42-95), and 44 patients had a dependent activity of daily living (ADL). Factors negatively associated with receiving post-ibrutinib therapy after discontinuation of ibrutinib were age ≥ 75 years (odds ratio [95% CI] 0.46 [0.26-0.80]) and emergency hospital admissions (0.37 [0.17-0.84]). Immediate post-ibrutinib therapy regimens were highly diverse, with BR (bendamustine, rituximab) only prescribed in more than 10% of patients. The median duration of post-ibrutinib therapy was 1.5 months (95% CI 1.07-2.07). The median overall survival from the end of ibrutinib therapy in patients regardless of the receipt of post-ibrutinib therapy (n = 247), in those who did not receive post-ibrutinib therapy (n = 110), and in those who received post-ibrutinib therapy (n = 137) was 5.6 months (95% CI 3.8-8.7), 2.3 months (95% CI 1.2-3.9), and 8.7 months (95% CI 5.6-13.8), respectively. The most common adverse event during post-ibrutinib therapy was infection, with the use of anti-infectives (17%).

Conclusions: Patients with MCL previously treated with ibrutinib have poor ability to carry out ADL and experience very poor outcomes. New safe, effective therapies are needed.