Abstract CT257: Hyperprogressive disease following bintrafusp alfa and DNA damaging chemotherapy in relapsed small cell lung cancer

Abstract Background: Small cell lung cancer (SCLC) is the most aggressive type of lung cancer. Current therapies have limited efficacy in SCLC, and despite a highly mutated genome, SCLC is largely unresponsive to immunotherapy. We sought to leverage the immune surveillance triggered by DNA damage in patients with relapsed SCLC using bintrafusp alfa, a bifunctional fusion protein targeting both PD-L1 and TGF-beta. Hyperprogressive disease (HPD), characterized by the rapid acceleration of tumor growth, has been reported in approximately 13% of patients treated with immune checkpoint inhibitors. However, the mechanistic basis is poorly understood. Methods: This is a safety run-in and phase II clinical trial. Cohort 1 enrolled patients with relapsed SCLC across Arms A (bintrafusp alfa 2400 mg q3 wks), B (bintrafusp alfa 2400 mg on D1 plus topotecan 1 mg/m2/day on D1-5 q3 wks), and C (bintrafusp alfa 1200 mg on D1 q2 wks plus temozolomide 200 mg/m2/day on D1-5 q4 wks). The primary endpoint was objective response rate (ORR). Results: Thirty-seven patients enrolled. Grade 3 treatment-related adverse events (TRAE) included transaminitis (27.0%), anemia (24.4%), lymphopenia (10.8%), and maculopapular rash (5.4%). Grade 4 TRAE included thrombocytopenia (8.1%), lymphopenia (5.4%) and transaminitis (5.4%). One patient experienced grade 5 tumor hemorrhage. By RECIST 1.1, partial responses were observed in 5 (13.5%), stable disease in 11 (29.7%), and progressive disease in 21 (56.8%) patients. Importantly, 13 (35.1%) patients developed HPD (≥ 2x increase in tumor growth rate from pre-trial vs on-trial, time to treatment failure ≤ 2 months, and ≥ 50% increase tumor burden). Changes in circulating cell-free DNA (n=20) tumor fraction using DELFI-TF, a mutation-independent, low-coverage whole genome sequencing approach, correlated with treatment responses. Pre-treatment serum from HPD (n=10 vs. 9 non-HPD) patients showed significantly lower levels of inflammatory cytokines (CXCL10, CCL13, CCL8, CCL19, TRAIL) and Granzyme H, and higher levels of anti-inflammatory cytokine IL10. Consistently, pre-treatment tumor transcriptomes of HPD (n=5 vs. 7 non-HPD) patients revealed suppression of IFN-gamma response, allograft rejection, and inflammatory response pathways. Conclusions: Concomitant TGF-beta and PD-L1 blockade is associated with a high frequency of HPD in SCLC patients. cfDNA could be critical for monitoring HPD. Tumor and blood immune signatures may inform the likelihood of HPD, with immune excluded tumors more likely to develop HPD. NCT Number: NCT03554473 Bintrafusp alfa was provided by EMD Serono (CrossRef Funder ID: 10.13039/100004755) Citation Format: Brett Schroeder, Nobuyuki Takahashi, Howard Yang, Renee Donahue, Zachary Skidmore, Alissa Konicki, Michael Nirula, Max Greenberg, George Chrisafis, Yang Zhang, Yo-Ting Tsai, Linda Sciuto, Samantha Nichols, Melissa Abel, Parth Desai, Rajesh Kumar, Christopher Schultz, Danielle Pinkiert, Chante Graham, Ajit Sharma, Justin Malin, Manan Krishnamurthy, Sophie Zhuang, Maxwell Lee, Lorenzo Rinaldi, Jeffrey Schlom, Lalage Wakefield, Anish Thomas. Hyperprogressive disease following bintrafusp alfa and DNA damaging chemotherapy in relapsed small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT257.