MEAN OVERALL SURVIVAL FROM THE PHASE 3 MIRASOL TRIAL OF MIRVETUXIMAB SORAVTANSINE VS INVESTIGATOR’S CHOICE OF CHEMOTHERAPY IN WOMEN WITH FR?-HIGH PLATINUM-RESISTANT OVARIAN CANCER (GOG 3045/ENGOT-OV55; NCT04209855)
Author(s)
Casey Cosgrove, MD1, Rowan E. Miller, PhD2, Eleonora Teplinsky, PhD3, Paolo Scollo, MD4, Nicoletta Colombo, MD, PhD5, Gerardo Colon-Otero, MD6, Toon Van Gorp, MD, PhD7, Dagmara Klasa-Mazurkiewicz, MD8, Beverly J. Long, MD9, Ingrid Boere, MD, PhD10, Tally Levy, MD11, Elsa Kalbacher, MD12, Shanthini Crusz, MD13, Peng-Hui Wang, MD, PhD14, Emily Whitman, MD15, Marie-Christine Kaminsky, MD16, María Merino, MD17, Jung-Yun Lee, MD18, Jan Kümmel, MD19, Francesc Sorio, MS, PharmD20, Zheng-Yi Zhou, PhD21, David Trueman, MSc22, Yajun Zhu, MBA, MS20, Brice Aouchiche, MSc, PharmD20, Anne-Claire Hardy-Bessard, MD23, Coriolan Lebreton, MD24.
1Gynecologic Oncology Group Foundation (GOG-F) and the Ohio State University Comprehensive Cancer Center, Columbus, OH, USA, 2Gynae-oncology Trials Group United Kingdom (GTG-UK) and Barts Health NHS Trust and University College London Hospital, London, United Kingdom, 3GOG-F and Valley Health System, Paramus, NJ, USA, 4Multicenter Italian Trials in Ovarian Cancer and Gynecologic Malignancies (MITO), Kore University, Enna, Italy, and A.O. Cannizzaro, Catania, Italy, 5Mario Negri Gynecologic Oncology group (MaNGO) and University of Milan-Bicocca and European Institute of Oncology IRCCS, Milan, Italy, 6GOG-F and Mayo Clinic, Jacksonville, FL, USA, 7Belgium and Luxembourg Gynaecological Oncology Group (BGOG) and University Hospital Leuven Kefir Cancer Institute, Leuven, Belgium, 8Polish Gynecologic Oncology Group (PGOG) and Medical University of Gdańsk, Gdańsk, Poland, 9GOG-F and Sarasota Memorial Healthcare System, Sarasota, FL, USA, 10Dutch Gynecological Oncology Group (DGOG) and Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, Netherlands, 11Israeli Society of Gynecologic Oncology (ISGO) and Wolfson Medical Center, Holon, Israel, 12Groupe d'Investigateurs National des Etudes des Cancers Ovariens et du sein (GINECO) and Centre Hospitalier Régional Universitaire (CHRU) de Besançon, Besançon, France, 13GTG-UK and Barts Health NHS Trust, London, United Kingdom, 14Taipei Veterans General Hospital, National Yang Ming Chiao Tung University, and Female Cancer Foundation, Taipei, Taiwan; China Medical University Hospital, Taichung, Taiwan, 15GOG-F and Zangmeister Cancer Center, Columbus, OH, USA, 16GINECO and Institut de Cancérologie de Lorraine - Alexis Vautrin, Vandœuvre-lès-Nancy, France, 17GEICO and Hospital Universitario Infanta Sofía, Madrid, Spain, 18Yonsei University College of Medicine, Seoul, Korea, Republic of, 19Eastern European Gynecologic Oncology Group (CEEGOG) and University Hospital Ostrava, Ostrava, Czech Republic, 20AbbVie Inc., North Chicago, IL, USA, 21Analysis Group, Inc., Boston, MA, USA, 22Source Health Economics, London, United Kingdom, 23GINECO and Centre CARIO - HPCA, Plérin, France, 24GINECO and Institut Bergonié, Bordeaux, France.
1Gynecologic Oncology Group Foundation (GOG-F) and the Ohio State University Comprehensive Cancer Center, Columbus, OH, USA, 2Gynae-oncology Trials Group United Kingdom (GTG-UK) and Barts Health NHS Trust and University College London Hospital, London, United Kingdom, 3GOG-F and Valley Health System, Paramus, NJ, USA, 4Multicenter Italian Trials in Ovarian Cancer and Gynecologic Malignancies (MITO), Kore University, Enna, Italy, and A.O. Cannizzaro, Catania, Italy, 5Mario Negri Gynecologic Oncology group (MaNGO) and University of Milan-Bicocca and European Institute of Oncology IRCCS, Milan, Italy, 6GOG-F and Mayo Clinic, Jacksonville, FL, USA, 7Belgium and Luxembourg Gynaecological Oncology Group (BGOG) and University Hospital Leuven Kefir Cancer Institute, Leuven, Belgium, 8Polish Gynecologic Oncology Group (PGOG) and Medical University of Gdańsk, Gdańsk, Poland, 9GOG-F and Sarasota Memorial Healthcare System, Sarasota, FL, USA, 10Dutch Gynecological Oncology Group (DGOG) and Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, Netherlands, 11Israeli Society of Gynecologic Oncology (ISGO) and Wolfson Medical Center, Holon, Israel, 12Groupe d'Investigateurs National des Etudes des Cancers Ovariens et du sein (GINECO) and Centre Hospitalier Régional Universitaire (CHRU) de Besançon, Besançon, France, 13GTG-UK and Barts Health NHS Trust, London, United Kingdom, 14Taipei Veterans General Hospital, National Yang Ming Chiao Tung University, and Female Cancer Foundation, Taipei, Taiwan; China Medical University Hospital, Taichung, Taiwan, 15GOG-F and Zangmeister Cancer Center, Columbus, OH, USA, 16GINECO and Institut de Cancérologie de Lorraine - Alexis Vautrin, Vandœuvre-lès-Nancy, France, 17GEICO and Hospital Universitario Infanta Sofía, Madrid, Spain, 18Yonsei University College of Medicine, Seoul, Korea, Republic of, 19Eastern European Gynecologic Oncology Group (CEEGOG) and University Hospital Ostrava, Ostrava, Czech Republic, 20AbbVie Inc., North Chicago, IL, USA, 21Analysis Group, Inc., Boston, MA, USA, 22Source Health Economics, London, United Kingdom, 23GINECO and Centre CARIO - HPCA, Plérin, France, 24GINECO and Institut Bergonié, Bordeaux, France.
OBJECTIVES: In MIRASOL, mirvetuximab soravtansine (MIRV) was the first therapy to improve median overall survival (OS) versus investigator’s choice of chemotherapy (ICC) in platinum-resistant ovarian cancer (PROC). Median OS and hazard ratios are common in oncology trials, but they only reflect when 50% mortality is reached and can mislead if proportional hazards are not met in the presence of long-term survivors. Mean OS, calculated using restricted mean survival time (RMST) and survival extrapolation, provides an assessment across the entire follow-up period to better capture long-term survival benefit.
METHODS: RMST was obtained from the area under the Kaplan-Meier (KM) OS curve using all follow-up data from MIRASOL (up to 40 months) for MIRV and ICC. Parametric modeling was used to extrapolate survival beyond data observation up to 60 months; models were chosen based on best statistical and visual fitting (log-logistic for MIRV and Weibull for ICC). An additional conservative scenario using Weibull in both arms was also used.
RESULTS: Mean OS differences measured with RMST favored MIRV over ICC at all time points, progressively increasing to a 4.11-month difference at 40 months (19.70 vs 15.59 months). Modeled mean OS differences favored MIRV by 5.26 months (21.01 vs 15.76 months) and 6.59 months (22.45 vs 15.86 months) at 48- and 60-month follow-up, respectively, with 4.75- and 5.30-month differences, respectively, when Weibull was used to model MIRV.
CONCLUSIONS: The 4.11-month mean OS advantage for MIRV at 40 months measured with RMST increased to nearly 7 months when modeled to 5 years, substantially exceeding the 3.51-month median OS benefit from the MIRASOL long-term follow-up. Mean OS captures survival benefit more appropriately given KM curve divergence over time. With the longer-term survivorship demonstrated in MIRASOL, mean survival provides valuable information for patients, physicians, and health technology assessment bodies and supports MIRV as the standard of care in FRα-positive PROC.
METHODS: RMST was obtained from the area under the Kaplan-Meier (KM) OS curve using all follow-up data from MIRASOL (up to 40 months) for MIRV and ICC. Parametric modeling was used to extrapolate survival beyond data observation up to 60 months; models were chosen based on best statistical and visual fitting (log-logistic for MIRV and Weibull for ICC). An additional conservative scenario using Weibull in both arms was also used.
RESULTS: Mean OS differences measured with RMST favored MIRV over ICC at all time points, progressively increasing to a 4.11-month difference at 40 months (19.70 vs 15.59 months). Modeled mean OS differences favored MIRV by 5.26 months (21.01 vs 15.76 months) and 6.59 months (22.45 vs 15.86 months) at 48- and 60-month follow-up, respectively, with 4.75- and 5.30-month differences, respectively, when Weibull was used to model MIRV.
CONCLUSIONS: The 4.11-month mean OS advantage for MIRV at 40 months measured with RMST increased to nearly 7 months when modeled to 5 years, substantially exceeding the 3.51-month median OS benefit from the MIRASOL long-term follow-up. Mean OS captures survival benefit more appropriately given KM curve divergence over time. With the longer-term survivorship demonstrated in MIRASOL, mean survival provides valuable information for patients, physicians, and health technology assessment bodies and supports MIRV as the standard of care in FRα-positive PROC.
Conference/Value in Health Info
2026-05, ISPOR 2026, Philadelphia, PA, USA
Value in Health, Volume 29, Issue S6
Code
CO101
Topic
Clinical Outcomes
Topic Subcategory
Clinical Outcomes Assessment
Disease
SDC: Oncology