Dr. Spira on the Examination of RTX-240 in a Phase 1 Trial with Solid Tumors

Alexander I. Spira, MD, PhD, FACP, research institute director, Thoracic and Phase 1 Trial Program, Virginia Cancer Specialists Research Institute, Virginia Cancer Specialists, clinical assistant professor, Johns Hopkins, discusses the examination of RTX-240 in a phase 1 trial (NCT04372706) with solid tumors.

The open label, multidose phase 1 trial evaluated RTX-240 in patients with relapsed/refractory or locally advanced solid tumors. RTX-240 is an allogeneic, off-the-shelf cellular therapy product candidate that is engineered to simultaneously present hundreds of thousands of copies of the costimulatory molecule 4-1BB ligand and IL-15TP in their native forms.

Data were presented at the 2022 AACR Annual Meeting, demonstrating that RTX-240 elicited some responses and prolonged stable disease. Phase 1 of the trial also established the recommended phase 2 dose of 5 x 1010 cells administered every 3 weeks.

Challenges with cellular therapies include their difficulty to produce and the toxicity associated with many of the current cellular therapies that require hospitalization, Spira says. This creates a need for a new generation that is less toxic off-the-shelf agents, which served as the rationale for developing RTX-240, Spira adds.

RTX-240 is unique because it is a red blood cell (RBC) therapy that engineers RBCs taken from donor cells to express 4-1BB and IL-15TP, Spira continues. The rationale is to use different aspects of the immune system to engage cancer cells and effectively attack them, Spira adds. Moreover, it is an off-the-shelf therapy and doesn't need to be personalized, Spira concludes.