R1 Therapeutics Launches with Oversubscribed $77.5M Series A to Advance Phase 2b Trial for Kidney Disease Drug AP306

R1 Therapeutics announced its launch on March 17, 2026, with an oversubscribed $77.5 million Series A financing co-led by Abingworth, DaVita Venture Group, and F-Prime, with participation from Curie.Bio, SymBiosis, and U.S. Renal Care.1 2

The funding will support global development of AP306, a first-in-class pan-phosphate transporter inhibitor for hyperphosphatemia in CKD patients on dialysis, including a Phase 2b trial starting later in 2026 with data expected in 2027.1 2 4 6

R1 secured exclusive global rights outside Greater China for AP306 from Alebund Pharmaceuticals; AP306 uniquely blocks active phosphate transport, unlike existing binders.1 2 4

AP306 originated from Chugai Pharmaceutical, licensed to Alebund in 2021, with Phase 2a data in January 2025 showing significant serum phosphate reduction and good tolerability.2 4

Led by CEO Krishna Polu, M.D., R1 aims to address high pill burden and poor adherence issues with current phosphate binders.1 2 4 5