Alebund Pharmaceuticals (Jiangsu) has received clearance from the US Food and Drug Administration (FDA) for its Investigational New Drug (IND) application for AP308, an engineered recombinant IgA protease being developed as a potential treatment for immunoglobulin A nephropathy (IgAN).

The company plans to initiate a first-in-human clinical trial of AP308, marking the transition of the drug candidate from preclinical research into clinical development.

AP308 is designed to target pathogenic IgA and IgA-containing immune complexes associated with IgAN. The candidate is based on an IgA protease derived from Thomasclavelia ramosa, a human commensal bacterium, and is engineered to cleave IgA1, galactose-deficient IgA1 (Gd-IgA1), polymeric IgA and IgA immune complexes.

According to Alebund, AP308 is designed to directly target IgA immune complexes and complement C3 deposited in the glomeruli. The candidate was developed using the company’s Long-Acting Protease Engineering Platform, which aims to improve stability, extend circulating half-life and reduce renal clearance while maintaining IgA-cleaving activity.

Preclinical studies have provided evidence of AP308’s potential activity in IgAN models. In a humanised mouse model, once-weekly subcutaneous dosing for eight weeks reduced circulating human IgA and IgA immune complexes by approximately 80 percent compared with controls. The treatment was also associated with near-complete clearance of glomerular IgA deposits, reduced proteinuria and improvements in kidney pathology.

In a separate preclinical study, a single dose of AP308 completely cleared pre-existing chronic glomerular IgA and complemented C3 deposits within seven days. The company reported no signals of liver or kidney toxicity or significant increases in anti-drug antibody titres following repeated dosing. The findings were published in May 2026 in Kidney International.

Alebund began collaborating with Peking University First Hospital in 2022 to explore IgA proteases as potential treatments for IgAN and subsequently developed AP308 as a drug candidate. The company holds global rights to develop, manufacture and commercialise AP308.

IgAN is characterised by the accumulation of IgA-containing immune complexes in the kidney’s glomeruli, which can cause inflammation and progressive kidney damage. Current treatment approaches primarily focus on reducing IgA production or controlling downstream inflammation, while direct removal of pathogenic immune complexes deposited in the kidney remains an area of investigation.

With FDA IND clearance, Alebund will now advance AP308 into clinical testing to evaluate its safety, tolerability and potential therapeutic activity in humans.