Calidi Biotherapeutics is a clinical-stage biotechnology company developing oncolytic virus therapies for cancer. Oncolytic viruses are engineered to preferentially infect and replicate within cancer cells, killing tumors directly and triggering an immune response, while leaving healthy cells unharmed. Calidi's lead program is its RedTail platform, which uses an engineered vaccinia virus modified to evade immune clearance and survive in the bloodstream, allowing it to travel to and replicate at metastatic tumor sites throughout the body. The lead RedTail compound, CLD-401, can also be engineered to express therapeutic payloads — such as an immune activator — directly at the tumor site. The key differentiator Calidi is pursuing is systemic (intravenous) delivery: the only FDA-approved oncolytic virus, Amgen's T-VEC, requires direct injection into tumors and cannot reach metastatic disease. CLD-401 is entirely preclinical, with a Phase 1 trial targeted for 2026. Calidi also has two earlier-stage programs: CLD-201, a vaccinia virus loaded into stem cells targeting solid tumors, which recently received FDA Fast Track Designation for soft tissue sarcoma and is entering Phase 1; and CLD-101, an adenovirus delivered via neural stem cells targeting brain tumors, currently in two investigator-initiated Phase 1 trials. Calidi has no approved products and no revenue, funding operations entirely through equity raises. The company outsources manufacturing to CDMOs and has no commercial infrastructure.