As reported on PharmaBiz, Alebund Pharmaceuticals has announced the first patient has been enrolled and treated in a global Phase IIb clinical trial evaluating AP306, an investigational therapy for hyperphosphatemia in patients undergoing maintenance hemodialysis. The multi-regional study is being conducted across sites in the United States and China and is jointly sponsored by Alebund and R1 Therapeutics.
AP306 is an oral, first-in-class pan-phosphate transporter inhibitor designed to reduce phosphate absorption in the intestine. Unlike traditional phosphate binders, which work by binding dietary phosphate in the gastrointestinal tract, AP306 targets three key phosphate transporters—NaPi-IIb, PiT-1, and PiT-2—to limit active phosphate uptake. The candidate was originally discovered by Chugai Pharmaceutical and later licensed to Alebund, which holds worldwide development and commercialization rights.
The newly launched Phase IIb study is a randomized, double-blind, placebo-controlled trial expected to enroll approximately 168 adults receiving maintenance hemodialysis. Participants will be assigned to one of six fixed-dose AP306 treatment groups or placebo for eight weeks. Investigators will assess safety, tolerability, and the drug’s ability to lower serum phosphate concentrations.
The primary outcome measure is change in serum phosphate levels from baseline to the end of treatment. Secondary objectives include evaluating the proportion of patients achieving target phosphate levels and the time required to reach phosphate control. Top-line data from the trial are anticipated in the first half of 2027.
Regulatory approval for the study has been obtained from China’s Human Genetic Resources Administration, and enrollment is underway, including at Peking University People’s Hospital, which serves as the lead site in China.
Hyperphosphatemia remains a major challenge for patients with chronic kidney disease (CKD) who require dialysis. Elevated phosphate levels are linked to complications such as vascular calcification, secondary hyperparathyroidism, bone disease, cardiovascular events, and increased mortality. Although dialysis, dietary restrictions, and phosphate-binding medications are widely used, many patients continue to struggle with phosphate control. Treatment limitations, including gastrointestinal side effects, high pill burden, and adherence difficulties, highlight the need for alternative therapeutic approaches.
Earlier clinical findings have been encouraging. In a completed Phase II study conducted in China, AP306 demonstrated a greater reduction in serum phosphate levels than sevelamer carbonate, a commonly prescribed phosphate binder. Patients receiving AP306 experienced an average decline of 2.51 mg/dL from baseline, compared with 1.08 mg/dL in the comparator arm. Nearly 95% of patients treated with AP306 achieved phosphate levels below 5.5 mg/dL during weeks seven and eight, versus roughly half of those receiving sevelamer carbonate.
The safety profile in that study was generally favorable. Gastrointestinal adverse events, primarily mild-to-moderate diarrhea, were the most frequently reported side effects and typically resolved within two weeks. No serious treatment-related adverse events were reported in the AP306 group, and discontinuation due to adverse events occurred in fewer than 5% of participants. Results from the trial were published in Kidney International Reports.
The therapy’s potential has also been recognized by regulators. In June 2024, China’s National Medical Products Administration granted AP306 Breakthrough Therapy Designation for the treatment of hyperphosphatemia in patients with chronic kidney disease.
The ongoing collaboration between Alebund and R1 Therapeutics stems from licensing and equity agreements signed in December 2025. Under the arrangement, R1 holds exclusive rights to develop, manufacture, and commercialize AP306 outside mainland China, Hong Kong, Macau, and Taiwan, while Alebund retains control in those markets. Both companies are responsible for conducting clinical and regulatory activities within their respective territories and are sharing data to support the global development program.
With dialysis populations continuing to grow worldwide and many patients remaining inadequately controlled on existing therapies, the Phase IIb trial marks an important step in determining whether AP306 can offer a new treatment option for managing hyperphosphatemia in CKD patients receiving dialysis.
