Rinatabart

Rinatabart (F131) is an IgG1-κ human antibody targeting FOLR1, with its corresponding isotype control being Human IgG1 kappa, Isotype Control. The Fc region of Rinatabart is engineered to reduce antibody-dependent cellular cytotoxicity ( ADCC ) and complement-dependent cytotoxicity ( CDC ) activities. The K D values of Rinatabart binding to human FOLR1 in two sets of BLI assays are 1.528 nM and 5.296 nM, respectively. Rinatabart shows significantly lower affinity for FOLR2 and mouse FOLR1, and no reliable specific binding to FOLR3 and rat FOLR1. Rinatabart can be used in studies of FOLR1 targeting and antibody-drug conjugates ^[1].

In Vitro, Rinatabart (F131) exhibits KD values of 1.528 nM and 8.148 nM for binding to human and cynomolgus monkey FOLR1, respectively, and shows significantly weaker or negligible binding to human FOLR2, human FOLR3, mouse FOLR1, and rat FOLR1^[1]. Rinatabart binds to FOLR1-positive JEG-3 cells with an EC50 of 1.549 nM, but does not specifically bind to FOLR1-negative PC-3 cells^[1]. Rinatabart (10 μg/mL; 0-4 h) is rapidly internalized into FOLR1-positive OVCAR-3, KB, JEG-3, NCI-H441 and OV90 cells, but not into FOLR1-negative PC-3 cells^[1]. Rinatabart (10 μg/mL; 0-23 h) undergoes time-dependent internalization into HeLa and RPTEC/TERT1 cells, and exhibits strong internalization ability among the tested anti-FOLR1 antibodies^[1].

References:
[1]. Zhao B. FOLR1 binding agents, conjugates thereof and methods of using the same. WO2022217022A1. 2022