Alebund Doses First Patient in Global Phase IIb Hyperphosphatemia Trial

Alebund Pharmaceuticals (09637.HK) has dosed the first patient in a global Phase IIb trial of AP306, a first-in-class oral drug for hyperphosphatemia in dialysis patients. The study, running at sites in the United States and China, will enroll about 168 patients across six fixed-dose regimens and a placebo arm over eight weeks. Topline results are expected in the first half of 2027.

AP306 targets a different biology than the phosphate binders that dominate the market. Instead of binding phosphate in the gut, it blocks three intestinal phosphate transporters – including NaPi-IIb and PiT-1 – that actively absorb phosphate into the blood. That could cut the pill burden and improve control in a patient population where current therapies often fall short, the company said.

Alebund already has Phase II data from a China-only trial. AP306 monotherapy lowered serum phosphate by 2.51 mg/dL from baseline, compared with 1.08 mg/dL for the active comparator sevelamer carbonate. At weeks seven and eight, nearly 95% of patients on AP306 had serum phosphate below 5.5 mg/dL, versus about 50% for sevelamer. The most common side effect was diarrhea, generally mild and resolving within two weeks. No serious adverse events were reported, and the discontinuation rate was below 5%. Results were published in Kidney International Reports.

Persistently elevated phosphate drives vascular calcification and secondary hyperparathyroidism, increasing the risk of cardiovascular events and death, according to studies cited in the release. About 76% of dialysis patients in China fail to hit the target serum phosphate range of 3.5 to 5.5 mg/dL, versus 52% in the U.S. and 39% in Japan. The number of dialysis patients in China is projected to grow from 1.3 million in 2025 to 3.4 million by 2035, a compound annual growth rate of about 10.1%, according to data cited in the company's June prospectus.

Phosphate binders like sevelamer and lanthanum carbonate work in the gut lumen, meaning patients must take them with every meal. AP306's transporter inhibition approach could allow less frequent dosing without meals, a major convenience advantage, the company said. The drug was originally discovered by Chugai Pharmaceutical and licensed to Alebund for global rights.

The trial has received Breakthrough Therapy Designation from China's National Medical Products Administration, a status that can accelerate review and provide more frequent regulator interaction. It signals that the NMPA sees AP306 as addressing a significant unmet need.

Alebund is running the Phase IIb trial jointly with R1 Therapeutics, a U.S.-based biotech focused on kidney disease. Under a December 2025 deal, Alebund licensed ex-China rights to AP306 to R1, while retaining full control in mainland China, Hong Kong, Macau, and Taiwan. The two companies are co-sponsors and each handles regulatory submissions in its own territory.

The hyperphosphatemia market is large and underserved. The global phosphate binder market was estimated at roughly $2.5 billion in 2025, with growth tied to the rising dialysis population. A drug that works through a different mechanism and requires fewer pills could capture significant share, analysts have said. Alebund's sales team is already in place in China, and the company said it plans to commercialize AP306 itself in that market if approved.

Alebund's pipeline includes seven investigational drugs and one marketed product, Mircera, for renal anemia. The most advanced candidate, AP301, has completed a registrational Phase III trial in China and is in a global MRCT. AP303 is in Phase I. The company has a manufacturing site in Yangzhou and a nephrology sales team in China.

The stock is listed on the Hong Kong Stock Exchange under ticker 09637. The company raised capital through an IPO in June 2026, with a prospectus that outlined the AP306 development plan. Investors have been watching the Phase IIb data as a near-term catalyst.

The Phase IIb trial is double-blind and placebo-controlled, with six fixed-dose arms. The primary endpoint is change in serum phosphate from baseline to the end of treatment. Secondary endpoints include the proportion of patients reaching the target range and time to phosphate control. The company said the data will inform the Phase III design.

Topline results are expected in the first half of 2027, a timeline that puts a potential new drug application filing in the 2028-2029 timeframe if the data are positive.