Rezubio, a clinical-stage biotechnology company, has completed dosing of the first cohort in a Phase 1 clinical trial evaluating RZ-520, an investigational inhaled therapy for chronic respiratory diseases. The programme has received clearance from the US Food and Drug Administration (FDA) and China’s National Medical Products Administration (NMPA).

The Phase 1 study is designed to evaluate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of RZ-520 in healthy volunteers. The completion of first-cohort dosing marks the transition of the candidate into clinical development.

RZ-520 is the second clinical-stage candidate developed using Rezubio’s proprietary Membrane-Anchored Drug Design (MADD) platform. The investigational therapy is designed for inhaled administration, with the aim of maintaining local drug exposure in the lungs while limiting systemic distribution.

According to Rezubio, preclinical studies of inhaled RZ-520 demonstrated therapeutic activity across multiple disease models, along with low systemic drug exposure. The company is now evaluating whether these findings translate into a favourable safety, pharmacokinetic and pharmacodynamic profile in humans.

Yusheng Xiong, CEO of Rezubio, said, “The dual IND clearances from the FDA and NMPA and first cohort dosing of RZ-520 mark a pivotal milestone for both this program and our MADD platform. Advancing our second MADD-derived drug candidate into clinical development further validates the power of our platform to design tissue-targeted therapies that address a broad spectrum of challenging diseases.”

RZ-520 is designed to provide sustained local exposure in the lung while limiting systemic distribution. The approach is intended to investigate whether tissue-selective drug delivery can improve the therapeutic profile of treatments for chronic respiratory conditions.

Rezubio’s MADD platform is focused on developing tissue-targeted therapeutics with prolonged local residence and tailored pharmacokinetic properties. The platform is being applied to potential therapies targeting cell-surface proteins in the respiratory and gastrointestinal tracts.