TOKYO, JAPAN, October 24, 2025 — Renalys Pharma, Inc. (Headquarters: Tokyo; Representative Director Chaiman & CEO; BT Slingsby; “Renalys”) and Chugai Pharmaceutical Co., Ltd. (Headquarters: Tokyo; President & CEO: Osamu Okuda; “Chugai”) today announced a definitive stock purchase agreement, under which Chugai will acquire Renalys (the “Transaction”). Renalys is advancing sparsentan in Japan; the medicine was initially developed by Travere Therapeutics, Inc. (“Travere”) and is approved in the United States and Europe for the treatment of IgA nephropathy. As part of the Transaction, Chugai will gain exclusive rights to develop and commercialize sparsentan in Japan, South Korea, and Taiwan.
Founded to close Asia’s persistent “drug lag,” Renalys develops innovative therapies for chronic kidney disease across Japan and the region. The company has completed primary endpoint data collection in its Japan Phase III clinical trial of sparsentan for IgA nephropathy, with topline results expected in Q4 2025. Renalys has also reached agreements with the Pharmaceuticals and Medical Devices Agency (PMDA) on registrational trial plans for focal segmental glomerulosclerosis (FSGS) and Alport syndrome in Japan.
Renalys believes that transferring sparsentan to Chugai, a company recognized for its rare-disease and nephrology expertise, will accelerate access for patients across Asia.
BT Slingsby, MD, PhD, MPH, Representative Director, Chairman & CEO, and Co-Founder of Renalys, stated: “Renalys was built to close Asia’s drug lag with a simple promise: patients should not have to wait years for proven therapies. By advancing sparsentan in Japan, we proved that the model works. Partnering with Chugai now scales it—accelerating access across Japan and the region and setting a new standard for how innovative renal medicines reach patients.”
Ryutaro Shimazaki, Chief Development Officer of Renalys, added:
“Chugai brings scale, speed, and deep know-how in renal disease. Together, we will align development with PMDA expectations, prepare clinicians for adoption, and focus on the practical steps that get sparsentan to patients sooner. Our goal is simple and urgent: convert strong data into real access for people living with IgA nephropathy, FSGS, and Alport syndrome.”
Source: https://renalys.com/renalys-pharma-to-be-acquired-by-chugai-pharmaceutical/