Efficacy and safety of therapeutic alpha-1-microglobulin RMC-035 in reducing kidney injury after cardiac surgery: a multicentre, randomised, double-blind, parallel group, phase 2a trial.

Background: Cardiac surgery invariably triggers acute kidney stress causing adverse renal outcomes. The AKITA study evaluated the efficacy and safety of RMC-035, a novel analogue of alpha-1-microglobulin, for reducing cardiac surgery-associated kidney injury. Methods: In this randomised double-blind placebo-controlled phase 2a study, we randomly assigned (1:1) adult hospitalised patients undergoing open-chest cardiac surgery at high risk for acute kidney injury (AKI) at 21 sites in North America and Europe to receive either RMC-035 (1.3 or 0.65 mg/kg) or placebo (1:1) for 2 days (5 intravenous infusions), stratified by region and renal function. Eligible patients had at least one pre-defined AKI risk factor. Patients with severe renal impairment (estimated glomerular filtration rate [eGFR] <30 mL/min/1.73 m Findings: Patient enrolment was stopped at interim analysis due to futility. Between March 31, 2022 and July 12, 2023, 177 patients (RMC-035: 89, placebo: 88) were randomised and treated. AKI rate for RMC-035 vs placebo was 50.6% (n = 45) and 39.8% (n = 35) (relative risk [RR]: 1.30, 90% confidence interval [90% CI]: 0.99, 1.71; p = 0.12). A short-lived creatinine increase was observed with the higher RMC-035 dose. Treatment with RMC-035 was associated with improved secondary renal outcomes at Day 90: placebo-adjusted eGFR change from baseline 4.3 mL/min/1.73 m Interpretation: In this proof-of-concept study, RMC-035 did not reduce AKI 72 h after cardiac surgery. Evaluations may have been confounded by a drug-induced transient creatinine increase in a subgroup of patients. RMC-035 was associated with improved secondary renal outcomes. These results merit further investigation and should be interpreted with caution, as the study was not powered for these outcomes. Funding: Guard Therapeutics.