SHANGHAI, China – May 6, 2026
Alebund Pharmaceuticals (Jiangsu) Limited has announced the completion of patient enrollment in its global Phase III pivotal clinical trial (RESPOND-2) evaluating AP301, a novel fiber-iron-based phosphate binder for the treatment of hyperphosphatemia in chronic kidney disease (CKD) patients on dialysis. The study enrolled 282 patients across the United States and China, exceeding the planned 264 participants, marking a critical milestone toward U.S. regulatory approval, as the trial is intended to serve as the single pivotal study for FDA registration. Led by prominent nephrology experts, the trial aims to address a major unmet need in CKD management, where current therapies fail to adequately control serum phosphate levels in a significant proportion of patients.
Innovative Trial Design and Clinical Strategy
RESPOND-2 is a double-blind, randomized, multi-regional Phase III trial designed to rigorously evaluate both efficacy and durability of AP301. The study includes three structured phases: an 8-week dose titration phase, a 24-week open-label treatment phase, and a 3-week randomized withdrawal phase, allowing for comprehensive assessment of phosphate control over time.
The primary endpoint focuses on reduction in serum phosphate levels, while the key secondary endpoint evaluates maintenance of phosphate control after treatment withdrawal. This layered design is strategically important, as it not only demonstrates initial efficacy but also long-term therapeutic sustainability, a critical factor in chronic diseases like CKD. Importantly, AP301 is engineered to offer higher phosphate-binding capacity, improved gastrointestinal tolerability, and reduced pill burden, directly targeting the key limitations of existing phosphate binders that often lead to poor patient adherence.
Strong Clinical Evidence and Competitive Positioning
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Data from the previously completed China Phase III trial (RESPOND-1) provides strong support for AP301’s clinical potential. In that study, AP301 demonstrated non-inferiority to sevelamer carbonate, a widely used standard therapy, with comparable reductions in serum phosphate levels at Week 12. More importantly, long-term data showed superior phosphate control, higher target attainment rates (66.7% vs. 58.6%), and lower daily dosing requirements, positioning AP301 as a potentially best-in-class oral phosphate binder.
The drug also showed sustained efficacy over 52 weeks, reinforcing its suitability for long-term management. Safety outcomes were favorable, with mild gastrointestinal side effects such as diarrhea and discolored feces, and notably, no evidence of iron accumulation, addressing a major concern associated with iron-based therapies. These results highlight AP301’s potential to significantly improve both clinical outcomes and patient compliance, which remains a major challenge in current CKD treatment paradigms.
Addressing a Large Unmet Medical Need
Hyperphosphatemia remains a critical and undercontrolled complication in CKD, affecting approximately 95% of dialysis patients globally. Despite existing treatment options, a large proportion of patients fail to achieve target phosphate levels, with studies indicating only 40–50% of patients reach guideline-recommended ranges. Elevated serum phosphate is strongly associated with vascular calcification, cardiovascular events, and increased mortality, making effective management essential.
Current therapies are often limited by high pill burden, gastrointestinal intolerance, and suboptimal adherence, creating a substantial gap in care. AP301 directly addresses these issues with a more patient-friendly formulation and improved tolerability profile, which could translate into better real-world effectiveness and reduced healthcare burden. Given the projected growth of the phosphate binder market, expected to reach USD 6 billion globally by 2035, AP301 is strategically positioned to capture significant market share if approved.
Regulatory Outlook and Commercial Potential
With enrollment now complete, Alebund is advancing toward data readout and regulatory submission, having already aligned with both the FDA and China’s NMPA on the development pathway. The company plans to leverage RESPOND-2 as the core registrational study for global approval, accelerating its timeline for commercialization. Backed by a diversified renal pipeline and established manufacturing capabilities, Alebund is positioning itself as a key innovator in kidney disease therapeutics. If successful, AP301 could redefine the standard of care for hyperphosphatemia, offering a more effective, safer, and patient-centric treatment option in a market with clear unmet needs.
Source: Alebund Pharmaceuticals press release
