Sift Biosciences, a UC Berkeley spinout developing a next-generation peptide immunotherapy platform that integrates AI, metagenomics, and high-throughput immune profiling,  announced the closing of a $3.7M Pre-Seed financing, co-led by Freeflow Ventures and Lifespan Vision Ventures, with participation from Valuence Ventures, Eisai Innovation, SBI US Gateway Fund and other early supporters.

Sift is building a new class of peptide-based immunotherapies designed to engage pre-existing memory T cells to overcome the lack of immunogenicity that limits current cancer immunotherapies. The company’s initial focus is on immunologically “cold” solid tumors, including microsatellite-stable colorectal and ovarian cancers, where patients have few effective treatment options.

“Most immunotherapies fail not because the immune system is weak, but because it’s never meaningfully engaged,” said Clare Lou, Ph.D., CEO and Cofounder of Sift Biosciences. “By harnessing infection-trained memory T cells, we’re developing a platform that can rapidly amplify immune responses in cancers that don’t respond to today’s treatments. This financing enables us to demonstrate in vivo proof-of-concept and advance our lead programs.”

Sift’s platform identifies microbial analogs of tumor-associated epitopes, enabling rapid activation of highly responsive memory T-cell populations without requiring de novo immune priming. Early preclinical studies support the potential for faster, more potent, and more durable immune responses than existing approaches.

“Sift is tackling one of the most fundamental challenges in immuno-oncology with a differentiated and biologically grounded strategy,” said Kevin Barrett, Managing Partner at Freeflow Ventures. “Since day one, Clare and the team have had a clear vision for building a scalable platform, and we’re excited to support them through this next phase of execution.”

In parallel with oncology, Sift is exploring applications in autoimmune disease, where its platform may enable selective expansion of regulatory T cells to restore immune tolerance.

“Sift’s approach reflects a shift toward precision immune modulation by leveraging the immune system’s existing memory,” said Altar Munis, Ph.D., Associate at Lifespan Vision Ventures. “The platform’s potential across both cancer and autoimmunity makes it especially compelling.”

Proceeds from the Pre-Seed round will support in vivo efficacy studies, expansion of Sift’s AI-powered peptide discovery engine, and lead candidate selection for its oncology pipeline.