Boutin, Mélina

PURPOSE The combination of the Bruton tyrosine kinase inhibitor ibrutinib with bendamustine-rituximab for first-line treatment of mantle cell lymphoma (MCL) prolonged progression-free survival (PFS), but without improvement in overall survival (OS), likely because of toxicity. Acalabrutinib was shown to be efficacious and less toxic than ibrutinib in a head-to-head trial in chronic lymphocytic leukemia and therefore might lead to better outcomes in MCL. METHODS Patients 65 years and older with previously untreated MCL received acalabrutinib (100 mg twice daily) or placebo (until disease progression or unacceptable toxicity), plus six cycles of bendamustine (90 mg/m 2 once daily; days 1 and 2) and rituximab (375 mg/m 2 as a single dose; day 1) followed by rituximab maintenance in responding patients for 2 years. Crossover to acalabrutinib at disease progression was permitted. The primary end point was PFS per the independent review committee; overall response rate and OS were secondary end points. RESULTS In total, 598 patients were randomly assigned, with 299 in each arm. At a median follow-up of 49.8 months using the reverse Kaplan-Meier method, the median PFS was 66.4 months in the acalabrutinib arm and 49.6 months in the placebo arm (hazard ratio [HR], 0.73 [95% CI, 0.57 to 0.94]; P = .0160). Benefit was seen across all subgroups, including those with high-risk features. Overall response/complete response rates were 91.0%/66.6% and 88.0%/53.5% in the acalabrutinib and placebo arms, respectively. OS was not significantly different (HR, 0.86 [95% CI, 0.65 to 1.13]; P = .27). Grade 3 or greater adverse events were reported in 88.9% and 88.2% in the acalabrutinib and placebo arms, respectively. CONCLUSION The combination of acalabrutinib with bendamustine-rituximab significantly improved PFS. Clinical benefit of acalabrutinib with bendamustine-rituximab was achieved with manageable toxicity.

Introduction Age correlates with survival in patients (pts) with DLBCL, which has a median age at diagnosis of 67 y. Recent therapeutic advances, including bispecifics and cell therapy, have promising efficacy, but safety and accessibility continue to be limited for older pts. The randomized, global, phase 3 ECHELON-3 study (NCT04404283) demonstrated a statistically significant and clinically meaningful improvement in overall survival (OS), progression-free survival (PFS), and overall response rate (ORR) with brentuximab vedotin (BV) + lenalidomide (Len) + rituximab (R; BV+Len+R) vs placebo+Len+R in pts with R/R DLBCL after ≥ 2 prior systemic therapies who were ineligible for hematopoietic stem cell transplant and/or chimeric antigen receptor (CAR) T-cell therapy. Here, we present safety and efficacy in pts aged ≥65 y. Methods In ECHELON-3, pts were randomized 1:1 to receive BV (1.2 mg/kg) or placebo every 3 weeks (q3w), in combination with R (375 mg/m2) q3w and Len (20 mg) once daily. Granulocyte colony-stimulating factor was required in all cycles. Efficacy was assessed by investigators per Lugano 2014 classification. The primary endpoint was OS, with key secondary endpoints of PFS and ORR. Other secondary endpoints included detailed safety and tolerability. This subgroup analysis comprises pts aged ≥65 y. P values are descriptive. Results A total of 155 pts aged ≥65 y were enrolled from April 2021 to November 2023 and randomized to BV+Len+R (n=79) or placebo+Len+R (n=76). The median age was 75 y (range, 65-89 y); 54% of pts were male, 59% were White, and 19% were Asian. Twenty-three percent and 54% had Ann Arbor stage III and IV disease, respectively, and 64% had high-intermediate or high International Prognostic Index scores (3-5) at enrollment. The most common DLBCL subtype was DLBCL not otherwise specified (58%). Twenty-nine percent of pts had transformed DLBCL. Approximately half (49%) of pts had primary refractory disease, and 81% had disease refractory to their most recent prior line of therapy. Seventy percent of pts had <1% CD30 expression via IHC; 48% of cases had germinal center B-cell origin. Prior CAR-T was reported in 21.9% of pts. At a median follow-up of 16.8 mo (95% CI, 14.3-19.5 mo), median OS was 15.9 mo (95% CI, 11.7 mo-not estimable [NE]) with BV+Len+R vs 8.5 mo (95% CI, 5.5-11.5 mo) with placebo+Len+R (hazard ratio [HR], 0.540; 95% CI, 0.351-0.830; P=.0043). Median PFS was 5.7 mo (95% CI, 4.1-12.7 mo) with BV+Len+R vs 2.8 mo (95% CI, 1.9-4.1 mo) with placebo+Len+R (HR, 0.478; 95% CI, 0.318-0.718; P=.0003). ORR was 70.9% (95% CI, 59.6%-80.6%) with BV+Len+R vs 46.1% (95% CI, 34.5%-57.9%) with placebo+Len+R (P=.0020); complete response (CR) rate was 45.6% vs 19.7%, respectively. Median time to CR was 1.61 mo with both BV+Len+R and placebo+Len+R (range, 1.2-7.3 vs 0.7-4.6 mo, respectively). Median duration of CR was 18.9 mo (95% CI, 12.4 mo-NE) with BV+Len+R vs 5.4 mo (95% CI, 2.8 mo-NE) with placebo+Len+R (HR, 0.416; 95% CI, 0.139-1.250). In total, 154 pts were evaluable for safety analysis (75 pts in placebo+Len+R group). The median number of cycles was 5 (range, 1-34) vs 3 (range, 1-31) in the BV+Len+R and placebo+Len+R groups, respectively. The percentage of pts with any treatment-emergent adverse event (TEAE) was similar between groups (97% with BV+Len+R and 99% with placebo+Len+R); grade ≥3 TEAEs occurred in 89% of pts in the BV+Len+R group and 76% in the placebo+Len+R group. Serious TEAEs and TEAEs leading to death were reported more frequently in the BV+Len+R group (62% and 13%, respectively) than the placebo+Len+R group (47% and 8%, respectively). More pts discontinued study treatment due to TEAEs in the BV+Len+R group than the placebo+Len+R group (20% vs 8%). In total, 39% of pts on BV+Len+R had a peripheral neuropathy event vs 27% of pts on placebo+Len+R; however, the majority of cases were grade 1 (22% and 17%, respectively). Additional information on older pts will be presented. Conclusions BV+Len+R demonstrated a clinically meaningful improvement in all key efficacy outcomes in pts aged ≥65 y, which is consistent with the overall ECHELON-3 population (median age 74 y; 70.5% of pts aged ≥65 y in BV+Len+R group). Differences in some safety endpoints are likely attributable to longer duration of treatment in the BV+Len+R group. No clinically meaningful safety trends in pts aged ≥65 y were identified. These results suggest that BV+Len+R may be an effective treatment option in older pts with R/R DLBCL.