SAN DIEGO, June 24, 2026
Calidi Biotherapeutics presented new preclinical data on CLD-501, its investigational in situ T-cell engager candidate targeting TROP-2, at the T-Cell Engager Therapeutic Summit. The findings demonstrated the capabilities of the company’s proprietary RedTail platform to locally express T-cell engagers within the tumor microenvironment (TME), aiming to overcome one of the biggest challenges limiting T-cell engager therapies in solid tumors.
RedTail Combines Localized T-Cell Activation with Targeted Gene Expression
RedTail is Calidi’s systemically delivered oncolytic virotherapy platform engineered to selectively target tumors while delivering therapeutic genetic payloads directly into the tumor microenvironment. The platform enables localized production of complex biologics, including cytokines and T-cell engagers, reducing systemic exposure and minimizing the risk of off-target toxicity. According to the presented data, RedTail successfully expressed both functional T-cell engagers and the IL-15 Superagonist (IL-15 SA), promoting simultaneous T-cell activation and enhanced immune-mediated tumor destruction within solid tumors.
CLD-501 Targets TROP-2 to Address Solid Tumor Challenges
Calidi is developing CLD-501 to target TROP-2, a cell-surface protein widely expressed in several solid tumors but historically difficult to target because of its presence in healthy tissues and the associated risk of on-target, off-tumor toxicity. By restricting T-cell engager expression to the tumor microenvironment, the RedTail platform is designed to improve treatment precision while limiting unwanted effects in normal tissues. The company also plans to expand this approach to additional targets, including EGFR, EpCAM, and Nectin-4.
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Cadrenal Expands Pipeline in Immune and Thrombotic Diseases
Calidi continues to advance its RedTail platform across multiple oncology programs. Its lead RedTail candidate, CLD-401, is designed to express high levels of IL-15 SA to activate CD8⁺ T cells, natural killer (NK) cells, and gamma delta (γδ) T cells within tumors, with an Investigational New Drug (IND) application expected by the end of 2026. Alongside pipeline expansion, the company is actively pursuing strategic partnerships to accelerate clinical development and broaden the application of its targeted genetic medicine platform for difficult-to-treat solid tumors.
Source: Calidi Biotherapeutics press release
