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, Calif., March 17, 2026 (GLOBE NEWSWIRE) -- 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.
About R1 Therapeutics
R1 Therapeutics is a clinical-stage biopharmaceutical company focusing on the development of first-in-class therapies for patients with kidney disease. Its lead program, AP306, targets hyperphosphatemia in patients with chronic kidney disease on dialysis, a condition associated with serious bone and cardiovascular complications and poorer outcomes when phosphate remains uncontrolled. AP306 is a first-in-class pan phosphate active transport inhibitor designed to block three key phosphate transporters in the gut, with the potential to deliver rapid and effective phosphate lowering with a significantly reduced treatment burden. R1 has licensed exclusive global rights outside of Greater China to AP306 from Alebund Pharmaceuticals and is advancing a global Phase 2b development program. R1 launched with an oversubscribed $77.5 million Series A financing in March 2026 co-led by Abingworth, DaVita Venture Group, and F-Prime, with participation from Curie.Bio, SymBiosis, and U.S. Renal Care. For more information, visit www.r1therapeutics.com and follow R1 on LinkedIn.
About Alebund Pharmaceuticals
Alebund was founded in Shanghai in 2018. The Company focuses on the discovery, development, manufacturing, and commercialization of novel therapies primarily for kidney diseases and their complications, as well as other chronic conditions, to bring better therapeutic options to patients in China and globally. Alebund has built a diversified and balanced pipeline of seven drug candidates and one commercialized product (Mircera®) targeting a broad range of renal indications, including chronic kidney disease (CKD) and CKD complications, such as hyperphosphatemia, renal anemia, IgA nephropathy, diabetic kidney disease, focal segmental glomerulosclerosis (FSGS), and autosomal dominant polycystic kidney disease (ADPKD). Alebund has completed the construction of its manufacturing site in Yangzhou that will supply both drug substance and drug products of its product candidates upon commercial launch. Alebund has also established a dedicated in-house commercialization team in China responsible for promoting the renal products.
About Abingworth
Abingworth is a leading transatlantic life sciences investment firm and part of the global investment firm Carlyle. Abingworth helps transform cutting-edge science into novel medicines by providing capital and expertise to top calibre management teams building world-class companies. Since 1973, Abingworth has invested in approximately 200 life science companies, leading to over 50 mergers and acquisitions and more than 75 IPOs. Abingworth's therapeutics-focused investments fall into three categories: seed and early-stage, development stage, and clinical co-development. Abingworth supports its portfolio companies with a team of experienced professionals at offices in London, Menlo Park (California), and New York. For more information, please visit www.abingworth.com.
About F-Prime
F-Prime is a global venture capital firm investing in healthcare and technology. For over 50 years, our venture capital group has had the privilege of backing great entrepreneurs building groundbreaking companies.
With over $4.8 billion under management and a global portfolio of over 400 companies, we champion those dedicated to creating positive change in the world. In healthcare, we focus on therapeutics, medtech and healthtech and services in a stage-agnostic fashion. Our healthcare fund has created or co-created over 35 companies including Denali, Beam, Innovent, and Orchard and has helped build many others including Blueprint Medicines, Iora Health, PatientPing, Devoted and Ultragenyx. F-Prime portfolio companies have seen more than 35 products and drugs approved by regulatory agencies worldwide. Our team of investors, engineers, doctors and scientists is committed to bringing the insight, domain expertise and relationships required to help our companies make a transformational impact.
F-Prime has offices in Cambridge, MA, San Francisco, CA, and London, UK. Please visit fprimecapital.com and follow us on Twitter and LinkedIn.
About DaVita Inc.
DaVita (NYSE:DVA) is a health care provider focused on transforming care delivery to improve quality of life for patients globally. As a comprehensive kidney care provider, DaVita has been a leader in clinical quality and innovation for more than 25 years. DaVita cares for patients at every stage and setting along their kidney health journey – from slowing the progression of kidney disease to helping support transplantation. This includes ensuring they are supported at home, in dialysis centers, in the hospital and in skilled nursing facilities. As of December 31, 2025, DaVita served approximately 295,000 patients at 3,242 outpatient dialysis centers, of which 2,657 centers were located in the United States and 585 centers were located in 14 other countries worldwide. DaVita has reduced hospitalizations, improved mortality, helped improve health access and worked collaboratively to propel the kidney care community to adopt a higher quality standard of care for all patients, everywhere. To learn more, visit DaVita.com/About.
About Curie.Bio
Curie.Bio is a $1.25B global venture capital firm that helps founders discover and develop important new medicines. The firm partners with founders and management teams by investing in existing companies, creating focused spinouts, and building companies from scratch. Curie.Bio's Seed model uniquely combines capital with hands-on drug development, operating as both a drug discovery copilot and an investor. Its 100+ person team of experienced drug hunters, drug makers, and operators works closely with founders on a day-to-day basis to improve decision-making and increase the probability of success. Curie.Bio's Breakout Fund supplies translational capital to support more mature companies through key clinical and regulatory milestones. Learn more at www.curie.bio.
About SymBiosis Capital Management, LLC
SymBiosis is an investment firm focused on advancing biotherapeutics innovations for serious and life-threatening diseases. The firm is an active, global investor in groundbreaking medicines across many disease areas and financing stages, with a focus on programs in, or about to enter, human trials. SymBiosis invests through a series of long-duration investment vehicles with significant capacity for new investments. For more information, please visit www.symbiosis.vc or follow us on LinkedIn.
About U.S. Renal Care
U.S. Renal Care, the largest privately held and fastest-growing dialysis provider in the nation, partners with nephrologists to care for more than 37,000 people living with kidney disease across 32 states in the U.S. Since 2000, U.S. Renal Care has been a leader in clinical quality, innovation, and operational excellence – delivering the best experience and outcomes for its patients. Visit USRenalCare.com to learn more.
References
- United States Renal Data System. 2024. USRDS 2024 Annual Data Report. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases.
- Mark, Patrick B et al. 2025. Global, regional, and national burden of chronic kidney disease in adults, 1990–2023, and its attributable risk factors: a systematic analysis for the Global Burden of Disease Study 2023. The Lancet, Volume 406, Issue 10518, 2461 - 2482
- United States Renal Data System. 2024. USRDS 2024 Annual Data Report. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases.
- Ketteler M, Block GA, Evenepoel P, et al. 2017 Executive summary of the 2017 KDIGO Chronic Kidney Disease–Mineral and Bone Disorder (CKD-MBD) Guideline Update: what's changed and why it matters. Kidney Int. 2017;92:26–36
- Fissel R et al. 2016 Phosphate binder pill burden, patient-reported non-adherence, and mineral bone disorder markers: Findings from the DOPPS. Hemodial Int. 2016 January ; 20(1): 38–49. doi:10.1111/hdi.12315
- Wang L, Zuo L, Shi M, et al. 2025 A pan-inhibitor of phosphate transporters AP306 in hemodialysis patients. Kidney Int Rep. 2025;10(4):1143–1151. doi:10.1016/S2468-0249(25)00063-4
For further information: Optimum Strategic Communications Mary Clark, Isabelle Abdou, Eleanor Cooper Tel: +44 20 3922 0900 Email: [email protected]
