ESTRO 2025 - Abstract Book

S158

Invited Speaker

ESTRO 2025

Many new discoveries are currently being made by the growing FLASH community. With FLASH, we have a wonderful opportunity to make a meaningful difference for our patients. In this talk I will highlight some of the most promising new biological applications of FLASH soon to be translated.

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Speaker Abstracts A phase 3 study of pembrolizumab + concurrent chemoradiotherapy for high-risk locally advanced cervical cancer: interim analysis 2 findings Domenica Lorusso 1 , Susan Lalondrelle 2 , Xiang Zhang 3 , Kazuhiro Takehara 4 , Jakub Cvek 5 , Shira Felder 6 , Hüseyin Akıllı 7 , Flora Zagouri 8 , Elisa Piovano 9 , Linn Wölber 10 , Line Bjorge 11 , Kara Romano 12 , Juan Francisco Alvarado 13 , Felipe Cruz 14 , Alejandro Acevedo 15 , Emma Fields 16 , Lucia Gonzalez-Cortijo 17 , Regina Berger 18 , Vincent Castonguay 19 , Ting Chang Chang 20 , Sarper Toker 21 , Karin Yamada 21 , Kan Li 21 , Annamaria Cerrotta 22 , Gabriella Macchia 23 1 Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Milan, Italy; Gynaecological Oncology Medical Unit, Humanitas San Pio X Hospital, Milan, Italy; Department of Women and Child Health, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy; and MITO, Rome, Italy. 2 Royal Marsden NHS Foundation Trust, Institute of Cancer Research and ENGOT, London, United Kingdom. 3 Department of Gynecological Oncology, Zhejiang Cancer Hospital, Hangzhou, China. 4 Department of Gynecologic Oncology, NHO Shikoku Cancer Center, Ehime, Japan. 5 Department of Oncology, University of Ostrava, North Moravia, Czech Republic; and CEEGOG, Prague, Czech Republic. 6 Department of Radiation Oncology, Sheba Medical Center, and ISGO, Ramat Gan, Israel. 7 Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Başkent University, Ankara, Turkey; and TRSGO, Istanbul, Turkey. 8 Department of Clinical Therapeutics, Alexandra Hospital and HeCOG, Athens, Greece. 9 Obstetrics and Gynaecology, Azienda Ospedaliero Universitaria Citta della Salute e della Scienza di Torino, Torino, Piemonte, Italy; and MaNGO, Milan, Italy. 10 Department of Gynaecology, University Medical Center Hamburg Eppendorf, Hamburg, Germany; and NOGGO, Berlin, Germany. 11 Department of Clinical Science, Centre for Cancer Biomarkers CCBIO, University of Bergen, Bergen, Norway; Department of Obstetrics and Gynecology, Haukeland University Hospital, Bergen, Norway; and NSGO, Copenhagen, Denmark. 12 Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, VA, USA. 13 Medical Oncology, Medi-K Cayala, Guatemala City, Guatemala. 14 Instituto Brasileiro de Controle do Câncer, São Paulo, SP, Brazil; Centro Universitário São Camilo, São Paulo, SP, Brazil; and GEICO, Madrid, Spain. 15 Medical Oncology, Oncocentro, Valparaiso, Chile. 16 Department of Radiation Oncology, Virginia Commonwealth University Health System, Richmond, VA, USA; and GOG Foundation, Philadelphia, PA, USA. 17 Department of Medical Oncology, Hospital Universitario Quirónsalud Madrid and GEICO, Madrid, Spain. 18 Department for Gynecology and Obstetrics, Medical University of Innsbruck and AGO-Austria, Innsbruck, Austria. 19 Centre-Hospitalier-Universitaire-de-Quebec, Laval University, Quebec City, QC, Canada. 20 Linkou Chang Gung Memorial Hospital, Chang Gung University Medical College, Taoyuan City, Taiwan. 21 Medical Oncology, Merck & Co., Inc., Rahway, NJ, USA. 22 Radiotherapy Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. 23 Radiation Oncology Unit, Responsible Research Hospital, Campobasso, Italy Purpose/Objectives: In ENGOT-cx11/GOG-3047/KEYNOTE-A18 (NCT04221945), pembrolizumab (vs placebo) plus concurrent chemoradiotherapy (CCRT) significantly improved PFS at interim analysis 1 (HR, 0.70 [95% CI, 0.55 ‒ 0.89]; P =0.0020) and OS at interim analysis 2 (IA2; HR, 0.67 [95% CI, 0.50 ‒ 0.90]; P =0.0040) in participants with high-risk locally advanced cervical cancer (LACC). Pembrolizumab plus CCRT had a manageable safety profile. Here we report additional results from IA2. Material/Methods: Participants with previously untreated, high-risk LACC (FIGO 2014 stage IB2 ‒ IIB node-positive or stage III ‒ IVA) were randomized 1:1 to 5 cycles of pembrolizumab 200 mg or placebo Q3W plus CCRT, then 15 cycles of pembrolizumab 400 mg or placebo Q6W. CCRT included 5 cycles (optional 6th dose) of cisplatin 40 mg/m 2 QW plus external beam radiotherapy (EBRT) followed by brachytherapy. Efficacy was evaluated in all randomized participants; safety was evaluated in all randomized and treated participants. Abstract: