R1 Therapeutics is developing category-defining, first-in-class therapies for patients with kidney disease, starting with lead asset AP306 for the treatment of hyperphosphatemia in patients with chronic kidney disease (CKD).

R1 launched in March 2026 with an oversubscribed $77.5 million Series A financing and a partnership with Alebund Pharmaceuticals, Ltd. to gain exclusive global development and commercial rights outside of Greater China for AP306.

AP306 is a first-in-class, pan phosphate active transport inhibitor in development as a monotherapy for the treatment of hyperphosphatemia in patients with CKD. It is distinguished as being the only agent that blocks the “active” transport of phosphate for the treatment of CKD. 

AP306 has been evaluated in a Phase 2a study in dialysis patients demonstrating significant reduction in serum phosphate levels with good safety and tolerability. R1 plans to initiate a Phase 2b study in 2026 to advance the clinical development of AP306, which has the potential to bring a fundamentally new and more effective approach to the management of hyperphosphatemia. 

Headquartered in the San Francisco Bay Area, California, R1 is backed by a global investor syndicate including Abingworth, F-Prime, DaVita Venture Group, part of DaVita Inc. (NYSE: DVA), Curie.Bio, SymBiosis, and U.S. Renal Care.

To find out more, visit our website: https://r1therapeutics.com/

R1 Therapeutics

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