Real-World Evaluation of Treatment Patterns and Clinical Outcomes Among Patients with Primary Mediastinal Large B-Cell Lymphoma Treated with Brentuximab Vedotin (BV)-Based Treatment Options in China
Authors: Xu Hengge , Li Wei , Wang Xianhuo , Zhang Huilai 
Published: December 2024

BACKGROUND: Primary mediastinal large B-cell lymphoma (PMBCL) is a rare, aggressive and clinically heterogeneous lymphoma with unique clinical, pathological, and molecular features. The high-risk factors for PMBCL include advanced stage, bulky disease (≥ 10 cm), extranodal involvement, and elevated serum lactate dehydrogenase. The Real World Study demonstrated a 5-year progression-free survival (PFS) rate of 56.5% with the R-CHOP regimen alone, which was significantly shorter than that of R-CHOP combined with radiotherapy and DA-EPOCH-R，with similar outcomes in the subgroup of patients with bulky dIsease. More than 80% of PMBCL express CD30, combination regimens based on brentuximab vedotin (BV) may be a potential therapeutic options for PMBCL. A phase I/II study of BV in combination with CHP as first-line therapy for patients with CD30-positive B-cell lymphoma reported an objective response rate (ORR) of 100% and a complete response (CR) rate of 81.8% in the PMBCL cohort. To date, there are few studies evaluating real-world treatment patterns and clinical outcomes of BV-based regimens for PMBCL in China, and our study aims to provide evidence of this regimen.

METHODS: This real-world study collected data from adults patients diagnosed with PMBCL at our center between May 2021 and April 2024. We retrospectively analyzed the treatment patterns, efficacy including ORR, CR rate, and safety in patients who received BV-based regimens.

RESULTS: A total of 12 adult patients diagnosed with PMBCL who received first-line therapy with BV-based regimen were enrolled in this study. The median age was 36 years (range, 21-55 years), and 41.7% were male. The Eastern Cooperative Oncology Group (ECOG) performance score ranged from 0-1. The percentage of patients with IPI ≥2 was 58.3% (7/12), and 50% (6/12) of patients were clinically staged as stage III-IV. No patients had central nervous system (CNS) or bone marrow involvement, and 2 patients had B symptoms. The median diameter of the largest mass was 10.0 cm (range, 4.9-13.2 cm), and 75% (9/12) of patients had a maximum mass over 7 cm. All patients were CD30 positive.

12 patients received first-line treatment with BV in combination with R-CHOP-like regimen. The median number of cycles for first-line therapy of BV (1.2mg/kg, 21 days/cycle) was 5.5 (range, 4-6 cycles). 2 patients were still receiving BV first-line therapy by July 3, 2024. During a median follow-up of 511 days (since the start of BV treatment), the best of ORR was 100% (12/12), the CR rate was 58.3% (7/12). The 10 patients who have finished first-line treatment had an ORR of 100% and a CR rate of 70% (7/10). Consolidation radiotherapy was performed in 50% (6/12) patients, of whom 3 had postradiotherapy evaluation results and no patients deepened response. By the date of follow-up, no patients progressed or died and 7 patients who achieved CR maintained in CR status.

The most common hematologic adverse event (AE) was leukopenia (66.7%, 8/12), followed by neutropenia in (33.3%, 4/12). Grade≥3 hematologic AEs occurred in 16.7% (2/12). The most common nonhematologic AE was hepatic injury, with a prevalence of 58.3% (7/12), all of which are grade 1. No patients experienced grade≥ 3 peripheral neuropathy and other nonhematologic AEs.

CONCLUSION: This real-world study explored the patterns and clinical efficacy of BV-based regimens for PMBCL in China. Our results show that BV-based regimens for patients with CD30-positive PMBCL demonstrate good efficacy and safety in real-world settings. This result needs to be confirmed in a larger cohort.