Rituximab following first-line bendamustine demonstrated significant OS and EFS real-world benefits in mantle cell lymphoma.
Maintenance rituximab (Rituxan) following first-line bendamustine (Treanda) plus rituximab (BR) exhibited significantly improved efficacy and survival outcomes vs no maintenance in patients with mantle cell lymphoma (MCL), according to data from a real-world analysis published in Blood Advances.1
Data from the analysis had a median follow-up of 69.6 months (95% CI, 64-73.8) for patients who received rituximab maintenance (n = 394) compared with 55.9 months (95% CI, 50.5-61.8) for those who did not receive rituximab maintenance (n = 309). Patients in the rituximab arm experienced a median event-free survival (EFS) of 49.9 months (95% CI, 43.3-61.9) compared with 29.7 months (95% CI, 26-36) for those in the no maintenance arm (HR, 0.58; 95% CI, 0.48-0.71; P < .001). Moreover, patients in the rituximab group achieved a median overall survival (OS) of 109.5 months (95% CI, 8.7-not evaluable [NE]) vs 74.2 months (95% CI, 59.9-86.4) for the no maintenance group (HR, 0.54; 95% CI, 0.41-0.72; P < .001).
“Rituximab maintenance therapy was associated with improved EFS and OS after first-line BR, supporting rituximab maintenance after frontline BR in patients with previously untreated MCL,” lead study author Yucai Wang, MD, PhD, and coauthors wrote in the journal.
Wang is an associate professor of medicine and oncology, as well as a consultant, in the Division of Hematology at Mayo Clinic in Rochester, Minnesota.
Investigators sought to examine the potential benefit of rituximab maintenance following first-line BR, as data from prospective clinical trials, including the phase 2 MAINTAIN trial (NCT06263491), have been inconsistent.1,2
The retrospective, multicenter study included patients who were at least 18 years old with a confirmed diagnosis of MCL with translocation or cyclin D1 expression.1 Patients also needed to have received frontline BR between January 2010 and December 2020.
If patients had received other MCL-directed systemic therapies in combination with BR, they were not included in the study.
Study investigators initially identified a total of 911 patients who were eligible for rituximab maintenance; however, 208 were excluded due to missing response data at the end of BR treatment (n = 48), not achieving a complete response (CR) or partial response (PR) by the end of BR treatment (n = 96), missing BR end of treatment date (n = 9), losing to follow-up within 3 months following the end of BR treatment (n = 14), or experiencing a progression event within 3 months of ending BR treatment (n = 41).
Patients received a median of 8 doses of rituximab (interquartile range [IQR], 5-12) and underwent a median 20.5-month duration of rituximab maintenance (IQR, 10.1-22.7).
Baseline characteristics revealed that among all patients who were eligible for rituximab maintenance (n = 703) had a median age of 71 years (range, 33-91) and were mostly male (78.1%) and White (92.3%). Most patients had an ECOG performance status of 1 or less (88.9%) and had bone marrow involvement with their MCL (72.3%). Stage III/IV disease was most common in patients (92.5%); additionally, many patients did not have bulky disease that was 5 cm or larger (73.8%). MCL International Prognostic Index scores broke down as low (20.6%), intermediate (40.8%) or high (38.6%) with 117 patients not reporting a score. Additionally, most patients did not have blastoid or pleomorphic morphology (90.7%), TP53 mutations (88.2%), or complex karyotype (82%).
Regarding patients who achieved a CR by the end of BR treatment (n = 509), those who received rituximab maintenance achieved a median EFS of 62.7 months (95% CI, 52.8-82.1) compared with 31.1 months (95% CI, 28-37.5) for those who did not received rituximab (HR, 0.52; 95% CI, 0.42-0.84; P < .001). Moreover, median OS rates for the rituximab group and the no maintenance group in this subgroup were 136.1 months (95% CI, 105.7-NE) and 75.3 months (95% CI, 63.5-91.9), respectively (HR 0.54; 95% CI, 0.41-0.72; P < .001).
Among patients who achieved a PR by the end of BR treatment (n = 113), those who received rituximab maintenance achieved a median EFS of 23 months (95% CI, 14.3-33.9) compared with 11.4 months (95% CI, 8-41.9) for those who did not (HR, 0.92; 95% CI, 0.59-1.45; P = .728). The median OS was 61.9 months (95% CI, 47.3-NE) and 45.1 months (95% CI, 32.2-112.2) for each group, respectively (HR, 0.73; 95% CI, 0.42-1.26; P = .260).
