Core Viewpoint - Sanofi received a negative opinion from the European Medicines Agency's Committee for Medicinal Products for Human Use (CHMP) regarding the marketing authorization application for Rezurock (belumosudil) for treating chronic graft-versus-host disease (cGVHD) in adults and pediatric patients, and the company plans to seek a re-examination of this opinion [1][3]. Group 1: Product Information - Rezurock is a first-in-class selective ROCK2 inhibitor, currently approved in 20 countries, including the US, UK, and Canada, for patients aged 12 years and older with cGVHD after failure of at least two prior lines of systemic therapy [4][5]. - Since its first approval in the US in July 2021, more than 17,000 patients with cGVHD worldwide have been prescribed Rezurock [4]. Group 2: Clinical Evidence - The efficacy and safety of Rezurock are supported by several clinical studies, including the randomized, multicenter ROCKstar phase 2 study, which demonstrated consistent efficacy and tolerability for patients with cGVHD, as well as durable clinical responses over a period of three years [3][4]. Group 3: Impact of cGVHD - cGVHD is a life-threatening complication affecting up to 50% of patients who undergo stem cell transplants, and it is a major cause of morbidity and late non-relapse mortality following such procedures [2][6].