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e19053 Background: DLBCL patients with co-expression of MYC (≥40%) and BCL2 (≥50%) by immunohistochemistry are considered as DE-DLBCL. The prognosis of DE-DLBCL is usually worse than DLBCL-NOS. The Smart Start trial had established the feasibility of chemotherapy-free targeted therapy before 1L chemotherapy. The BTK inhibitor Zanubrutinib (Z) or epigenetic drug Chidamide (C) with R-CHOP regimen has a potential synergistic effect in the treatment of DE-DLBCL. Under the inspiration of Smart Start, this trial aim to explore the feasibility of ZCR±CHOP regimen in TN DE-DLBCL. Methods: This is a multicenter, open-label, single-arm phase 2 study (NCT05527912) conducted in China. If patients achieve complete response (CR) after cycle-2 (C2), ZCR will be continued for up to 8 cycles. Otherwise, ZCR-CHOP will be given for another 6 cycles. The primary endpoint is CR rate at the end of treatment (CRR-EOT); secondary endpoints included ORR (overall response rate) ,2y-PFS, and 2y-OS. Plasma samples were collected at baseline, C2 and the EOT. In evaluable samples, circulating tumor DNA (ctDNA) assays were performed. Results: From February 2023 till now, 34 TN DE-DLBCL patients were enrolled, with 32 patients evaluable. The median age was 52y (range: 22-68), 55.9% were male, 79.4% were Non-GCB (Table 1). 12 patients who achieved CR by C2 were continued with RCZ chemo-free therapy, and CHOP were added to the 14 PR and 3 SD patients. In the 32 evaluable patients, ORR after C2 of RCZ was 81.25% (26/32, CR 37.5%, PR 43.75%, SD 9.4%, PD 9.4%). Up to now, 12 patients have completed 8 courses (C8) and all of them have achieved CR, both ORR and CR are 100% (12/12). 3 patients withdrew due to PD. For safety information in the trial, 64.3% patients reported grade (G)-3/4 AEs. In the Chemo-Free subgroup, only 4 patients (36.4%, 4/11) reported G-3/4 AEs. the majority of G-3/4 AEs is hematological events, including leukopenia, neutropenia and thrombocytopenia. The CR rate at C2 was 66.7% (6/9) in patients with negative baseline ctDNA results. The patients with BCL6 fusion of ctDNA at baseline were more prone to PD (3/4, 75.0%). Compared to baseline, plasma ctDNA levels decreased significantly after C2. 29 patients were evaluable for ctDNA after C2, 100% (12/12) of C2-CR patients and 58.8% (10/17) of non-C2-CR patients were negative, P=0.023. Compared with Non-C2-CR patients, the number of detected mutations and average VAF level were decreased in C2-CR patients. Conclusions: This trial demonstrates ZCR±CHOP could be a promising regimen with active antitumor effect and acceptable toxicity in TN DE-DLBCL patients. Clinical trial information: NCT05527912 .
Li et al. (Sat,) studied this question.