R1 Therapeutics, a clinical-stage biopharmaceutical company focused on kidney disease, has launched with an oversubscribed $77.5 million Series A financing to advance a first-in-class treatment for hyperphosphatemia in patients with chronic kidney disease.
The funding round was co-led by Abingworth, DaVita Venture Group, and F-Prime, with participation from Curie.Bio, SymBiosis, and U.S. Renal Care. Alongside the financing, the company secured exclusive global rights outside of Greater China to develop and commercialize AP306 from Alebund Pharmaceuticals.
The proceeds will support R1’s global development program for AP306, including a Phase 2b clinical trial expected to begin later this year.
AP306 is being developed as a monotherapy for hyperphosphatemia in patients with chronic kidney disease on dialysis. Unlike existing phosphate-lowering therapies that rely on binding phosphate to inhibit passive transport, AP306 targets active phosphate transport by blocking three key transporters in the gastrointestinal tract. The company believes this mechanism could offer improved efficacy with a lower pill burden and better tolerability.
Hyperphosphatemia remains a significant unmet need in chronic kidney disease management. More than 500,000 patients in the United States and approximately four million worldwide receive dialysis, yet over 40% of U.S. patients fail to meet treatment targets. Poorly controlled phosphate levels are associated with bone and cardiovascular complications, increasing the risk of morbidity and mortality. Current standard-of-care phosphate binders are often limited by low binding capacity, high pill burden, and gastrointestinal side effects, contributing to poor adherence.
AP306 has already demonstrated promising results in a Phase 2a study in dialysis patients, showing significant reductions in serum phosphate levels along with favorable safety and tolerability.
R1 Therapeutics is led by Co-Founder, President, and CEO Krishna Polu, M.D., a nephrologist with more than 20 years of experience in the biopharmaceutical industry. He is joined by Co-Founder L. Mary Smith, Ph.D., who serves as Chief Operating Officer and leads development activities.
The company’s board includes representatives from its lead investors along with independent leadership, positioning R1 to advance its clinical pipeline and address longstanding challenges in kidney disease treatment.
AP306, previously known as EOS789, was originally discovered by Chugai Pharmaceutical and later licensed to Alebund Pharmaceuticals. Investigational New Drug applications for the therapy are active in both the United States and China as development progresses.
KEY QUOTES:
“We are excited to be launching R1 Therapeutics in partnership with Alebund and with support from a strong, experienced syndicate including DaVita and U.S. Renal Care, recognized global providers transforming kidney care. This backing, plus a differentiated clinical-stage asset, positions us to address one of the most persistent challenges in managing patients with chronic kidney disease. AP306 represents a fundamentally new approach to treating hyperphosphatemia. By blocking the active transport of phosphate through three different phosphate transporters in the GI tract, initial clinical studies suggest AP306 has the potential to deliver superior efficacy with substantially lower pill burden compared to current phosphate binder therapies. If successful, AP306 should redefine the class of phosphate lowering therapies and become the treatment of choice for the management of hyperphosphatemia.”
Krishna Polu, M.D., Co-Founder, President, And CEO Of R1 Therapeutics
“R1 Therapeutics brings together an exceptional leadership team with deep nephrology expertise and a clear vision for advancing AP306. This asset addresses a significant unmet need in a large, underserved patient population. We are delighted to partner with R1 Therapeutics to develop AP306 globally and improve outcomes for the millions of CKD patients struggling with inadequate phosphate control.”
Gavin Xia, CEO Of Alebund Pharmaceuticals
