Redwood City, CA – March 17, 2026 – R1 Therapeutics has officially emerged from stealth mode, announcing an oversubscribed $77.5 million Series A financing to support the development of a novel treatment for chronic kidney disease (CKD) patients suffering from hyperphosphatemia.
The financing round was co-led by Abingworth, F-Prime Capital, and DaVita Venture Group, with additional participation from Curie.Bio, SymBiosis, and U.S. Renal Care.
Focus on First-in-Class Therapy
Alongside its launch, R1 Therapeutics has secured an exclusive global license (outside Greater China) from Alebund Pharmaceuticals for AP306, a first-in-class pan-phosphate transporter inhibitor.
AP306 is being developed as a monotherapy for hyperphosphatemia, a serious condition characterized by elevated phosphate levels in the blood, commonly affecting patients with CKD on dialysis.
Unlike traditional phosphate binders that target passive phosphate absorption, AP306 is designed to block active phosphate transport, potentially offering a differentiated and more effective treatment approach.
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Addressing a Significant Unmet Need
Hyperphosphatemia remains a major clinical challenge. In the United States alone, over 500,000 patients on dialysis are affected, with millions more globally. Poorly controlled phosphate levels are associated with bone disorders and cardiovascular complications, contributing to increased morbidity and mortality.
Current standard-of-care therapies, including phosphate binders, often suffer from low efficacy, high pill burden, and poor patient adherence, highlighting the need for innovative treatment options.
Advancing Clinical Development
Proceeds from the Series A financing will primarily support the global development program for AP306, including a planned Phase 2b clinical trial expected to begin later in 2026.
Early clinical data from prior studies have demonstrated significant reductions in serum phosphate levels with favorable safety and tolerability, positioning AP306 as a promising candidate in the CKD treatment landscape.
Strategic Positioning
R1 Therapeutics is positioning itself as a clinical-stage biopharmaceutical company focused on kidney disease, aiming to deliver first-in-class therapies that address unmet needs in nephrology.
The company’s partnership with Alebund Pharmaceuticals and backing from leading life sciences investors underscores strong confidence in its approach and pipeline.
cGxPwire Insight
The launch of R1 Therapeutics reflects continued investor interest in renal disease and metabolic disorder therapies, particularly those targeting high-burden conditions like CKD. With a differentiated mechanism of action and a clear clinical roadmap, AP306 could represent a meaningful advancement in the treatment of hyperphosphatemia.
Source: R1 Therapeutics press release.
