R1 Therapeutics launches with oversubscribed USD 77.5m Series A. March 17, 2026 R1 Therapeutics, a clinical-stage biopharmaceutical company headquartered in Redwood City, California, has launched with an oversubscribed Series A financing totaling USD 77.5 million. The company is focused on developing therapies for chronic kidney disease, the lead program targeting hyperphosphatemia in dialysis patients. R1 acquired exclusive global rights outside of Greater China to that program - AP306, a pan phosphate transporter inhibitor - via a license deal with China-based Alebund Pharmaceuticals announced alongside the Series A. The round was co-led by Abingworth, F-Prime, and DaVita Venture Group, part of DaVita Inc. (NYSE: DVA), with participation from Curie.Bio, SymBiosis, and US Renal Care. The company said proceeds will fund a global development program for AP306, including a Phase IIb study planned to begin later this year. This is R1 Therapeutics' first disclosed funding round, coinciding with the company's formal launch. AP306, previously known as EOS789, was originally discovered by Chugai Pharmaceutical Co. and subsequently licensed to Alebund Pharmaceuticals, which conducted a Phase IIa study in hemodialysis patients in China. Results from that trial, published in Kidney International Reports, showed statistically significant reductions in serum phosphate with a tolerable safety profile. AP306 is described as the only clinical-stage agent that blocks active phosphate transport via three GI-tract transporters - NaPi-2b, PiT-1, and PiT-2 - distinguishing it from phosphate binders, which inhibit passive transport and have been the standard of care for six decades. More than 40% of US dialysis patients fail to reach phosphate targets with existing therapies, which carry high pill burden and GI tolerability issues, the company said. R1 is led by co-founder, president, and CEO Krishna Polu, M.D., a nephrologist with more than 20 years of biopharmaceutical experience. Co-founder L. Mary Smith, Ph.D., who previously served as chief development officer at SpringWorks Therapeutics, joins as chief operating officer. Your email address will not be published. Required fields are marked *

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