Japan-based Renalys Pharma and Chugai Pharmaceutical have announced a definitive stock purchase agreement, under which Chugai will acquire Renalys. Renalys is advancing sparsentan in Japan; the medicine was initially developed by Travere Therapeutics, Inc. 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 commercialise 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 recognised for its rare-disease and nephrology expertise, will accelerate access for patients across Asia.
Chugai will pay up to JPY 16 billion in cash tied to regulatory milestone achievements for sparsentan and to net sales in Japan, South Korea, and Taiwan.
