Sift Biosciences, a Berkeley-based biotechnology company developing an AI-powered peptide immunotherapy platform, has raised $3.7 million in an oversubscribed pre-seed funding round co-led by Freeflow Ventures and Lifespan Vision Ventures. Participants include Valuence Ventures, Eisai Innovation, and SBI US Gateway Fund. The capital will fuel platform development, including planned in vivo proof-of-concept studies for T-cell boosters targeting immunologically cold solid tumors and autoimmune diseases.
AI Peptides Target Cold Tumors
The round comes amid heightened investor interest in next-generation immunotherapies leveraging AI and microbiome insights. Sift's approach stands out by mining microbial-derived peptides to activate pre-existing memory T cells, sidestepping the slower process of de novo T-cell priming required by many CAR-T and TIL therapies.
Solid tumors, which comprise the majority of cancer cases, often prove resistant to existing immunotherapies. Immunologically 'cold' tumors like microsatellite-stable colorectal and ovarian cancers exhibit low T-cell infiltration and poor responses to checkpoint inhibitors such as PD-1/PD-L1 blockers. Current solutions struggle to ignite robust immune responses in these environments, leaving a significant unmet need for patients facing low response rates.
Microbial Boosters Amplify T Cells
Sift Biosciences' proprietary platform integrates AI, metagenomics, and high-throughput T-cell screening to identify 'T-cell booster' peptides. These peptides harness pre-existing immunity from the human microbiome, delivering faster and more potent responses compared to traditional methods that rely on engineering new T cells. Unlike CAR-T therapies, which face manufacturing complexities and limited solid tumor efficacy, Sift's peptides offer a modular, off-the-shelf potential for both oncology and autoimmunity—where regulatory T cells could be modulated to dampen overactive responses.
The company's dual pipeline addresses oncology's cold tumor challenge while extending to autoimmune diseases, differentiating it from oncology-focused peers like those developing TILs or bispecifics.
Investors signal strong validation for this novel strategy. Freeflow and Lifespan Vision, known for backing deep tech biotech, co-led the round, joined by strategic pharma players Eisai Innovation—highlighting potential for peptide tech in drug development—and SBI US Gateway. This mix of growth capital and strategic investment underscores confidence in Sift's ability to translate microbiome-derived insights into clinical assets, positioning it for preclinical milestones.
Immunotherapy Market Draws Early Capital
The immunotherapy sector continues to attract significant early-stage funding as AI accelerates discovery. Sift's oversubscribed raise reflects broader trends in precision immunology, where platforms targeting microbiome-T cell interactions are emerging. With non-dilutive support including a $1M grant, Sift joins a cohort of AI-biotech spinouts pushing boundaries in solid tumor access.
Strategic pharma involvement points to partnerships ahead, as big players seek differentiated modalities beyond antibodies and cell therapies.
Berkeley Spinout's Elite Team
Founded in 2024 as a UC Berkeley spinout, Sift is led by microbiologist and bioinformatician Yue Clare Lou—a Forbes 30 Under 30 honoree—and immunologist Maddie Williams. The seven-person team draws from Juno Therapeutics, Bristol Myers Squibb, and Celgene, bringing expertise in T-cell engineering and multiple patents to bear on peptide discovery.
Platform Advances to In Vivo POC
With $3.7M in tow plus a $1M grant, Sift plans to execute in vivo proof-of-concept studies, advancing its preclinical platform toward validation in cold tumor models and autoimmune indications.