R1 Therapeutics launches with oversubscribed $77.5 million Series A financing to advance first-in-class treatment for hyperphosphatemia in patients with chronic kidney disease

• Series A co-led by Abingworth, DaVita Venture Group, and F-Prime with participation from Curie.Bio, SymBiosis, and U.S. Renal Care
• Partnership with Alebund Pharmaceuticals to gain exclusive global development and commercial rights outside of Greater China for AP306, a differentiated pan phosphate transporter inhibitor, the only agent blocking the active transport of phosphate
• Advancing Phase 2b clinical development of AP306 as a monotherapy for hyperphosphatemia in patients with chronic kidney disease on dialysis

Redwood City, California – 17 March 2026 – R1 Therapeutics, Inc (“R1”), a clinical-stage biopharmaceutical company focused on the development of first-in-class therapies for patients with kidney disease, today announced its launch with an oversubscribed $77.5 million Series A financing, along with the exclusive global license to develop and commercialize AP306 outside of Greater China from China-based Alebund Pharmaceuticals, Ltd. (“Alebund”). The financing was co-led by Abingworth, F-Prime, and DaVita Venture Group, part of DaVita Inc. (NYSE: DVA), with participation from Curie.Bio, SymBiosis, and U.S. Renal Care.

Proceeds from the Series A financing will fund R1's global development program of AP306 in partnership with Alebund, including a Phase 2b study planned to start later this year.

AP306 is a first-in-class, pan phosphate transporter inhibitor in development as a monotherapy for the treatment of hyperphosphatemia in patients with chronic kidney disease (CKD). Whereas currently available approved phosphate lowering therapies work by inhibiting “passive” transport of phosphate through binding phosphate and other mechanisms, AP306 is distinguished as being the only agent that blocks the “active” transport of phosphate for the treatment of CKD.

The treatment of hyperphosphatemia is an important component in managing CKD patients, especially those on dialysis, yet it represents a high unmet need. More than 500,000 patients in the United States¹ and four million worldwide receive dialysis,² however more than 40% of US patients fail to achieve treatment targets.³ Uncontrolled hyperphosphatemia contributes to bone and cardiovascular disease, leading to significant risk of morbidity and mortality.⁴ Current phosphate binders, which have been the standard of care for 60 years, are limited by low binding capacity, high pill burden and poor gastrointestinal tolerability, contributing to poor adherence and limiting the effectiveness of these therapies.⁵

AP306 has been evaluated in a Phase 2a study in dialysis patients, with results published in Kidney International Reports⁶ demonstrating significant reduction in serum phosphate levels with good safety and tolerability.

R1 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 and a track record of pipeline advancement and company creation. Joining Dr. Polu is fellow Co-Founder, biotech veteran, and former Chief Development Officer at SpringWorks Therapeutics, L. Mary Smith, Ph.D., who will serve as Chief Operating Officer and lead R1’s development activities.

“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,” said Krishna Polu, M.D., Co-Founder, President and CEO of R1 Therapeutics. “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.”

“R1 Therapeutics brings together an exceptional leadership team with deep nephrology expertise and a clear vision for advancing AP306,” said Gavin Xia, CEO of Alebund Pharmaceuticals. “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.”

R1’s Board of Directors will be comprised of  Andrew Sinclair, Ph.D., Managing Director at Abingworth; Tom Musgrave, Vice President, Pharma Strategy at DaVita Venture Group; Chong Xu, Ph.D., Partner at F-Prime; Ben Auspitz, Managing Partner at Curie.Bio; Steve Landau, M.D., Independent Director; and Krishna Polu, M.D., Co-Founder, President and CEO of R1.

AP306 (previously known as EOS789) was originally discovered and developed by Chugai Pharmaceutical Co., Ltd. and subsequently licensed to Alebund Pharmaceuticals. Investigational New Drug (IND) applications to support AP306’s clinical development are open in both the United States and China