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1723 Exploration of Rituximab Plus Lenalidomide(R2)in Newly Diagnosed Diffuse Large B Cell Lymphoma with Adverse Prognostic Factors As Maintenance Therapy

Program: Oral and Poster Abstracts
Session: 627. Aggressive Lymphomas: Pharmacologic Therapies: Poster I
Hematology Disease Topics & Pathways:
Research, Clinical Research, Real-world evidence
Saturday, December 7, 2024, 5:30 PM-7:30 PM

Jia Li1, Ou Bai, MD/PhD2*, Yangzhi Zhao, MD/PhD3*, Wei Guo, MD/PhD3* and Xingtong Wang, MD/PhD3

1Department of Hematology, The First Hospital of Jilin University, Changchun, NY, China
2The First Hospital of Jilin University, Changchun, China
3Department of Hematology, The First Hospital of Jilin University, Changchun, China

Background: Approximately 40% of diffuse large B-cell lymphoma (DLBCL) experience relapse or refractory after R-CHOP treatment, with those relapsing within 2 years having worser prognosis. Maintenance therapy can sustain or deepen disease remission and prolong progression-free survival. Studies have shown that the R2 regimen effectively improves survival in elderly or chemotherapy-intolerant patients with relapsed/refractory DLBCL(Guido, G Blood 2023). Here, we report a single-center retrospective study on the efficacy and safety of first-line maintenance therapy with the R2 regimen in DLBCL patients with poor prognostic factors. Additionally, we explore the optimal administration of lenalidomide.

Methods: Newly diagnosed DLBCL Pts, from February 2019 to March 2024, aged ≥18 y, with at least one of the following adverse prognostic factors achieved CR or PR after R-CHOP/CHOP like therapy, entered maintenance therapy with the R2 regimen ( 28-day cycles of 25./20 mg oral lenalidomide from days 1 to 21 and 12-week cycles of IV rituximab 375 mg/m2 on day 1.) as a maximum of 2-year maintenance therapy. Control Group were those from December 2005 to December 2022, DLBCL Pts with at least one adverse prognostic factors achieved CR or PR after first-line treatment did not receive maintenance therapy. The primary endpoint was progression-free survival (PFS) .Adverse prognostic factors: 1. IPI3 or aaIPI2 with at least one of the following factors:① Tumor diameter6.0 cm;② Extranodal involvement at ≥ 1 sites;③ Lymphoma involving at least one of the following special sitescentral nervous system, testis, breast, adrenal gland, uterus2. Immunohistochemistry showed double expression (Bcl-2≥50% and c-Myc≥40%) or P53 positive;3. FISH showed double-hit or triple-hit (MYC rearrangement, Bcl-2 and/or Bcl-6 rearrangement) or TP53 mutation.

Results: A total of 187 pts were enrolled, 35 pts received R2, 152 pts involved in control group. ① The R2 maintenance therapy group primarily consisted of elderly (77.1%). 83.3% were in the advanced stages (III-IV). Intermediate-high/high-risk patients accounted for 80%. Extranodal involvement at ≥1 site (97.1%) was a major characteristic. Involvement of special sites was present in 17.2% of the cases. Before maintenance therapy, 68.6% of the patients achieved CR. The non-maintenance group included 152 patients with baseline characteristics similar to the R2 maintenance group. ② The median follow-up time in R2 group was 33 months. The median DOR, PFS, and OS were not reached in. Compared to the control group, R2 maintenance therapy significantly improved DOR (1 year: 93.5% vs. 68.7%; 2 years: 83.9% vs. 60.0%, P=0.001), PFS (1 year: 96.9% vs. 70.8%; 2 years: 85.2% vs. 61.5%, P=0.001), and OS (1 year: 96.7% vs. 80.3%; 2 years: 84.2% vs. 71.4%, P=0.006). R2 maintenance therapy significantly improved PFS whether the disease achieved CR(P=0.030) or PR(P=0.045). ③ Subgroup analysis showed that patients who achieved CR before or during maintenance therapy had longer PFS (P=0.013) and OS (P=0.041). Additionally, in this study, 7 patients with PR converted to CR during R2 maintenance therapy, and their PFS (P=0.470) and OS (P=0.498) were not significantly different from those who achieved CR with first-line treatment. ④ Prognostic factor analysis using the COX proportional hazards regression model showed no significant difference in PFS (P=0.772) and OS (P=0.719) between double-expressor DLBCL receiving R2 and non-double-expressor. However, patients with involvement of special sites had significantly worse PFS (P=0.024) and OS (P=0.012) compared to those without such involvement. The most common grade 3/4 adverse event was neutropenia (14.3%), with a higher incidence in patients with bone marrow involvement (37.5%). Exploration of the optimal dosing regimen for lenalidomide: Patients tolerated best at the 20 mg dose. 20 mg dose with a 28-day cycle had similar efficacy to the 25 mg, but significantly fewer grade 3/4 adverse events.

Conclusion: In DLBCL patients with adverse prognostic factors, R2 maintenance therapy after first-line treatment could deepen disease remission (PR converting to CR) and provided significant survival benefits (PFS, OS). The recommended dose of lenalidomide in R2 is 20 mg on days 1-21 of a 28-day cycle. Special attention should be paid to neutropenia in patients with bone marrow involvement.

Disclosures: No relevant conflicts of interest to declare.

*signifies non-member of ASH