Abstract P115

Efficacy and safety of prolgolimab monotherapy or in combination with bendamustine in second-line therapy for r/r classic Hodgkin lymphoma: trial in progress (Prolgo-HL)

Backgrounds Prolgolimab (Prolgo), an anti-PD-1 inhibitor, has proven effective and safe for melanoma treatment. Expected efficacy extends to classic Hodgkin lymphoma (cHL). Incorporating Prolgo into PET-adapted second-line therapy may achieve extended remission or cure in cHL patients, sparing autologous stem cell transplantation (auto-HSCT). Methods This prospective, multicenter, single-arm, phase 2 trial includes adult patients with histologically confirmed relapsed or refractory (r/r) cHL after first-line therapy without history of PD-1 inhibitor therapy (NCT05757466). The study protocol is outlined in Figure 1. Response assessments performed every 3 months by PET-CT or CT, using LYRIC and Lugano criteria. Adverse events (AE) were assessed using NCI CTCAE v5.0. The primary endpoint was overall response rate: complete response (CR) and partial response (PR). Secondary endpoints included the frequency of AE, overall survival (OS), progression-free survival (PFS), and duration of response (DOR). We performed intention-to-treat (ITT) analysis for safety and per-protocol (PPA) analysis for efficacy, due to deviation from protocol in 3 patients in one study center. Results A total of 20 pts with r/r cHL were enrolled between April 2023 and April 2024. The PPA included 17 pts. Fourteen pts (82%) completed all 6 cycles of Prolgo. Five pts (36%) achieved CR and 6 (43%) - PR. Among those achieving CR and completing 24 cycles, all responses were maintained at the end of treatment (n=2, 14%). One patient each demonstrated indeterminate response, stable disease, and disease progression. Eight patients (47%) were switched to the Prolgo-bendamustine arm. All patients who completed combined therapy achieved an objective response (CR n=4, PR n=1), and in two cases, auto-HSCT was performed. With a median follow-up of 7 months (2-11), all pts were alive. In the safety ITT analysis (n=20), the rate of grade (gr) 1-2 AE was 55% (n=11), and gr 3 AE - 20% (n=4: rash, diabetes mellitus onset, pneumonia, and renal colic). Conclusion This study is the first to assess Prolgo efficacy and safety as second-line therapy for cHL, aiming to avoid auto-HSCT in early CR patients. Preliminary data demonstrate an anticipated toxicity profile and promising efficacy with the potential for chemotherapy and auto-HSCT avoidance.

Authors

Liudmila Fedorova, Kirill Lepik, Polina Kotselyabina, Anastasia Semenova, Valerie Shpirko, Stanislav Volchenkov, Vladislav Markelov, Andrey Chekalov, Ilya Zyuzgin, Gayane Tumyan, Natalia Mikhailova, Alexander Kulagin