Actym Therapeutics Reports Preclinical Data Demonstrating ACTM-838’s Ability To Generate Anti-Tumor Immunity

Actym Therapeutics, a Berkeley-based biotechnology company focused on the discovery and development of transformational immunotherapies to treat cancer, has announced that an abstract highlighting detailed in vivo and in vitro preclinical data of its lead candidate, ACTM-838, was accepted for presentation at the Society for Immunotherapy of Cancer (SITC) 37th Annual Meeting, to be held virtually and at the Boston Convention & Exhibition Center from November 8 to 12, 2022.  ACTM-838 is Actym’s lead candidate from its proprietary STACT platform and encodes an engineered IL-15 payload (IL-15plex) and engineered STING payload (eSTING). The data showed ACTM-838 to offer powerful efficacy as a single agent, including when used in checkpoint refractory tumors, and to work synergistically when used in combination with anti-PD1 therapies.

“The data we are presenting at SITC highlights the power of ACTM-838 to overcome the highly immunosuppressive tumor microenvironment and generate durable anti-tumor immunity in preclinical models,” said Christopher Thanos, Ph.D., Actym’s President, CEO, and Cofounder. “ACTM-838 is systemically delivered, with potent, tumor-specific effects. These preclinical data give us confidence in our approach to comprehensively and broadly re-program the tumor microenvironment as we prepare to enter the clinic in 2023.” 

Research highlights include:

• Broad and comprehensive reprogramming of the immunosuppressive tumor microenvironment (TME) to an anti-tumor immunophenotype occurs after safe, intravenous dosing with ACTM-838. 
• Profound immune infiltration and activation across T-cells, macrophages, dendritic cells, and B-cells, after treatment with ACTM-838.
• Potent ACTM-838 single agent efficacy and highly synergistic efficacy in combination with anti-PD1 therapies in checkpoint refractory breast and colon cancer tumor models, inducing complete responses in both regimens. As a monotherapy, ACTM-838 generated durable immunity upon re-challenge in cured animals.
• Increased T-cell infiltration and activation, and decreased T-regs after treatment with ACTM-838. Myeloid cell re-polarization to a preferred, dual M1/M2 phenotype was also observed.  
• Overcoming a known immune evasion strategy for tumors (downregulation of MHC class I) and observing MHC class I upregulation in the TME, after ACTM-838 treatment. 

“Our preclinical work has shown ACTM-838’s efficacy in transforming the tumor microenvironment both as a potent single agent and in synergy with anti-PD1 therapies,” said Chan Whiting, Ph.D., Actym’s Chief Development Officer and Head of Research and Development. “We look forward to entering the clinic next year with this new and potentially powerful therapeutic approach, and bringing hope to cancer patients with limited treatment options.”

SITC Presentation Details:

ABSTRACT #1065:  ACTM-838, a microbial-based immunotherapy that enriches in solid tumors after IV dosing, reverses the immunosuppressive TME to promote durable anti-tumor immunity, alone and in combination with anti-PD1 in mice  

DATE: Thursday, November 10, 2022

TIME: 9:00 AM EST

PRESENTER: Akshata Udyavar, Ph.D., Senior Director, Immunology & Translational Sciences, Actym Therapeutics

LOCATION:  Boston Convention & Exhibition Center, Boston, MA USA