Calidi Biotherapeutics, Inc. announced that it entered into a collaboration agreement with SIGA Technologies in the first quarter of 2024, to support the development of Calidi?s systemic and targeted RTNova (CLD-400) virotherapy platform, which has the potential to provide a universal treatment for all tumor types. Calidi will initially focus on developing the RTNova platform for lung cancer and metastatic (or advanced stage) solid tumors which account for the majority of cancer deaths. The long-term collaboration between Calidi and SIGA aims to harness the capabilities of SIGA?s TPOXX, an antiviral agent effective against vaccinia virus.

The initial focus for the collaboration will be on testing the capacity of TPOXX to become a safety switch to manage RTNova?s spread in vivo. RTNova, an enveloped vaccinia virus, is designed to survive in the bloodstream, target multiple tumor sites, and kill tumor cells while altering the tumor immune microenvironment. This novel therapeutic approach not only facilitates easier administration but also broadens the potential patient population who can benefit from this treatment .

The U.S. Food and Drug Administration (FDA) approved oral TPOXX in July 2018 for the treatment of smallpox to mitigate the impact of a potential outbreak or bioterror attack. Preclinical studies have demonstrated TPOXX?s efficacy against all orthopox viruses that have been tested, including vaccinia (published in The New England Journal of Medicine, July 2018). The un mechanism of action of TPOXX coupled with published efficacy in animal studies make it an important addition to the development of vaccinia-based cancer therapies.