Longitudinal real-world surveillance of infection outcomes in CAR-T and bispecific therapy recipients: the CLARITY study protocol

Introduction Infections are a leading cause of non-relapse mortality following chimeric antigen receptor T-cell therapy (CAR-T) and bispecific antibody (BsAb) therapies. However, infection data from clinical trials are often incomplete, lack pathogen-level detail and rarely capture late infectious complications.

This C AR-T treatment in L ymphoma: A nalysis of R isk of I nfection following T herap y (CLARITY) study aims to generate real-world, longitudinal infection data with extended follow-up to characterise infection timing, including late events and inform risk prediction in patients with lymphoma and myeloma receiving novel immunotherapies. Methods and analysis CLARITY is a multicentre observational cohort study across six Australian centres enrolling adults treated with CAR-T or BsAb therapies.

A co-designed REDCap (Research Electronic Data Capture) instrument captures infections classified as microbiologically defined, clinically defined or fever of unknown origin, using internationally standardised definitions. Patients were enrolled between 2019 and 2023, with at least 2 years follow-up per patient, allowing time-updated data on immunosuppressive exposures, haematological recovery and prophylaxis.

Multivariable regression and landmark analyses will estimate infection incidence and identify dynamic risk factors over time.