Paris-based Signadori Bio SAS has closed an EUR 11.1 million seed extension round to advance its in vivo monocyte engineering platform for solid tumours, with Taiho Ventures joining existing backers Sofinnova Partners and Invivo Partners in the financing.
Proceeds will be directed toward advancing lead programme SiB-2101 to lead candidate nomination, continued development of the proprietary monocyte engineering platform, and expansion of the company's scientific and operational teams. Sofinnova Partners has backed the company since its formation in March 2025 through a strategic partnership with Gustave Roussy, Europe's largest cancer center. Invivo Partners joined as a co-investor in April 2025, ahead of the formal seed round closure.
Signadori Bio was founded by Dr. Jean-Luc Perfettini and Professor Nathalie Chaput, both based at Gustave Roussy, where the underlying science was developed. The platform centers on the role of p21 (CDKN1A) as a regulator of myeloid anti-tumor activity. Overexpression of p21 in monocytes suppresses SIRPα, the receptor that binds to the CD47 "don't eat me" signal on tumor cells, enabling monocyte-derived macrophages to engulf and destroy cancer cells that would otherwise evade immune clearance. Engineered macrophages then release interferon-γ, which reprograms surrounding immunosuppressive tumor-associated macrophages, reshaping the broader tumor microenvironment.