AbbVie announced the U.S. Food and Drug Administration (FDA) approved IMBRUVICA® (ibrutinib) for the treatment of patients with relapsed/refractory (R/R) marginal zone lymphoma (MZL) who require systemic therapy and have received at least one prior anti-CD20-based therapy.1 This indication is approved under accelerated approval based on overall response rate (ORR), and continued approval may be contingent upon verification and description of clinical benefit in a confirmatory trial. IMBRUVICA is jointly developed and commercialized by Pharmacyclics LLC, an AbbVie company, and Janssen Biotech Inc. The approval in MZL is based on data from the Phase 2, open-label, multi-center, single-arm PCYC-1121 study, which evaluated the safety and efficacy of IMBRUVICA in MZL patients who require systemic therapy and have received at least one prior anti-CD20-based therapy. The efficacy analysis included 63 patients with three sub-types of MZL: mucosa-associated lymphoid tissue (MALT; N=32), nodal (N=17) and splenic (N=14). The ORR was achieved in nearly half (46%) of the patients (95% CI: 33.4-59.1) as assessed by an Independent Review Committee (IRC) using criteria adopted from the International Working Group criteria for malignant lymphoma, with efficacy observed across all three MZL sub-types. The median time to response was 4.5 months (range, 2.3-16.4 months). In the trial, 3.2% of patients had a complete response (CR) and 42.9% of patients had a partial response (PR). The median duration of responses was not reached (NR) (range 16.7 months to NR).