Alebund Pharmaceuticals, an integrated biopharmaceutical company focused on innovative therapies for renal diseases and related chronic conditions, has completed patient enrollment in the global phase 3 pivotal multi-regional clinical trial of AP301 for the treatment of hyperphosphatemia in chronic kidney disease (CKD) patients undergoing maintenance dialysis.

The trial, known as RESPOND-2 (Study AP301-HP-03), was conducted across the United States and China and enrolled a total of 282 dialysis-dependent CKD patients with hyperphosphatemia, including 138 participants in the US and 144 in China. The study is led by Dr Geoffrey A. Block of US Renal Care, while Professor Xiaoqiang Ding of Zhongshan Hospital, Fudan University serves as the China principal investigator.

AP301 is a next-generation fiber-iron-based phosphate binder designed to offer stronger phosphate-binding capability, improved gastrointestinal tolerability, minimal risk of iron overload and easier administration without the need for chewing before swallowing. The therapy is intended to improve patient adherence and enhance long-term phosphate control.

RESPOND-2 is a double-blind, randomised, multi-regional phase III clinical trial evaluating AP301 against an ineffective low-dose comparator. The study includes an eight-week dose titration phase, a 24-week open-label treatment period and a three-week randomised withdrawal phase. The primary endpoint focuses on changes in serum phosphate levels from baseline following the dose titration period.

Based on prior clinical data, Alebund has reached an agreement with the US Food and Drug Administration (FDA) that RESPOND-2 will serve as the single pivotal study supporting US regulatory registration for AP301.

Hyperphosphatemia remains one of the most common complications among CKD patients, particularly those on dialysis. Persistently elevated phosphate levels are associated with vascular calcification, secondary hyperparathyroidism, renal bone disorders, cardiovascular complications and increased mortality risk. Existing phosphate binders are often associated with gastrointestinal side effects, high pill burden and poor patient compliance, resulting in inadequate phosphate control for many patients worldwide.

The company highlighted that AP301 had previously demonstrated strong efficacy and safety outcomes in its completed China phase 3 trial, RESPOND-1, which enrolled 474 participants across 50 clinical sites. In that study, AP301 achieved non-inferior phosphate reduction compared with sevelamer carbonate, while also showing sustained long-term phosphate control, higher target attainment rates and lower daily dosing requirements.

The safety profile of AP301 was reported to be favourable, with the most common adverse events being mild diarrhoea and discoloured feces. No evidence of iron accumulation was observed during the 52-week treatment period.

Following the positive clinical progress, Alebund stated that it has aligned with China’s National Medical Products Administration (NMPA) and plans to submit a New Drug Application (NDA) for AP301 in the near future.

The company noted that completion of enrollment in the global phase 3 study marks a significant milestone in the global registrational development of AP301 and reflects Alebund’s growing capabilities in advancing international clinical programmes for kidney disease therapies.