ASCO 2024 Meeting Report — Hematologic Malignancies

The 2024 American Society of Clinical Oncology (ASCO) annual meeting, held May 30 to June 3 in Chicago, highlighted important advances in treatment of hematologic cancers. Here, Associate Editor Dr. Michael Williams reviews several key trials.

The benefit of rituximab maintenance (RM) therapy following induction immunochemotherapy in mantle cell lymphoma (MCL) has not been fully defined. This multicenter, retrospective study assessed outcomes among patients treated from 2007 to 2020 with front-line bendamustine plus rituximab (BR) without autologous stem cell transplantation consolidation. Patients in complete or partial remission at 3 months post–BR completion were included (abstract 7006).

Of 613 patients, 318 (52%) received RM. Stage, histologic subtype, and poor-risk biomarkers did not differ between patients who did and did not receive RM, but the RM cohort was slightly younger (70 vs. 72 years) and had a higher proportion of males (78% vs. 69%). At a median follow-up of 61.3 months, the event-free survival was significantly improved in the RM cohort (median, 47.1 vs. 29.7 months; hazard ratio, 0.59), as was overall survival (median, 11.3 vs. 6.2 years; HR, 0.57). The median number of RM doses was 10 (interquartile range, 5–12).

These real-world data support the use of RM following BR in patients with nontransplant MCL. Current practice generally utilizes a schedule of one dose every 2 months for 2 to 3 years. Infection risks need to be considered, given bendamustine-associated immunosuppression and RM's effects on humoral immune responses.

The treatment of acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS) has shifted in recent years to nonintensive chemotherapy with a hypomethylating agent plus venetoclax among elderly patients and those with medical comorbidities. To assess the impact of a collaborative-care model combining palliative and oncologic management, researchers conducted a randomized, prospective, multicenter study in patients with newly diagnosed or relapsed or refractory AML/MDS (abstract LBA6508). Patients were enrolled within 30 days of treatment initiation into the collaborative care model (monthly outpatient palliative care consultations plus 2 or more weekly visits during any hospital admissions) versus usual care (palliative care consultation provided upon request).

Of 222 eligible patients, 115 were enrolled. End-of-life discussions were documented in the electronic health record for significantly more patients in the collaborative care cohort than the usual care cohort (97% vs. 69%; P<0.001). Among the 71 patients who died, the time from end-of-life discussion to death (the primary endpoint) was 41 days in the collaborative care cohort versus 1.5 days in the usual care cohort. Quality of life (QOL) was improved in the collaborative care group, with fewer hospital admissions during the final 30 days of life. There was no difference in utilization of hospice services.

These findings are consistent with other reports showing QOL benefits and reduced hospital resource utilization with early engagement of palliative care services for patients with advanced, poor-risk malignancies. The collaborative model is thus to be encouraged for patients with poor-risk AML/MDS who are not candidates for intensive chemotherapy.

Brentuximab vedotin (Bv), an antibody-drug conjugate targeting CD30, has shown activity in CD30-negative lymphomas, possibly related to low-level CD30 expression below the threshold of detection by immunohistochemistry, or other mechanisms. The industry-sponsored, multinational, phase 3, double-blind ECHELON-3 trial compared the efficacy and safety of Bv plus lenalidomide/rituximab (R2) versus placebo plus R2 in patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL; abstract LBA7005). In this planned interim analysis of overall survival (OS) in the intent-to-treat population (the primary endpoint), 112 patients received BvR2 and 118 received R2. The median age was 71 years (range, 21–89); patients had received a median of three prior lines of therapy (range, 2–8), and 29% had received prior CAR T-cell therapy. Tumor cell CD30 expression was negative (<1%) in 68% of patients.

At a median follow-up of 16.4 months, the median OS was significantly longer in the BvR2 group than the R2 group (13.8 vs. 8.5 months; HR, 0.629; P = 0.0085). Overall response rates were higher with BvR2 compared with R2 in CD30+ patients (72.2% vs. 50.0%) and in CD30− patients (60.5% vs. 37.5%). Of note, rates of complete remission response in the BvR2 group were similar in CD30+ and CD30− cases, at 38.9% and 40.8%, whereas in the R2 group, rates were 37.5% versus 15%, respectively. Adverse events were more frequent with BvR2, including neutropenia and peripheral neuropathy.

The BvR2 regimen enhanced survival and overall response but not complete response in patients with relapsed/refractory DLBCL, with expected but manageable toxicities. More-sensitive analysis of CD30 status may be helpful to identify patients most likely to benefit from the addition of Bv to R2. The regimen may also find application as bridging or sequential treatment with CAR T-cell or bispecific antibodies.