CAR T-Cell Therapy Claims: End of REMS & KX Modifier Requirement

Related CR Release Date: December 9, 2025
MLN Matters Number: MM14204
Effective Date: June 26, 2025 
Related Change Request (CR) Number: CR 14204
Implementation Date: February 6, 2026 
Related CR Transmittal Numbers: R13432CP & R13432CP1

CR 14204 tells you about:

  • Providers to administer Chimeric Antigen Receptor (CAR) T-cell therapy in an FDA Risk Evaluation Mitigation Strategy (REMS) - approved facility
  • The KX modifier on Medicare Part B claims for CAR T-cell therapy

Make sure your billing staff know about these changes no longer required as of June 26. 2025.

View the complete CMS Medicare Learning Network (MLN) Matters (MM)14204.

Last Updated Dec 18 , 2025