Sift Biosciences Closes $3.7M Pre-Seed Round for Peptide Immunotherapy Platform

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 $3.7 million pre-seed financing. The oversubscribed round was 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.

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.

The CEO and Cofounder stated that by harnessing infection-trained memory T cells, the company is developing a platform that can rapidly amplify immune responses in cancers that don't respond to today's treatments. The financing enables the company to demonstrate in vivo proof-of-concept and advance its lead programs.

Proceeds from the pre-seed financing will be used to advance in vivo efficacy studies, further develop and scale Sift's AI-driven peptide discovery engine, and support lead candidate nomination across its oncology pipeline.

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. The company was founded in 2024 as a UC Berkeley spin-out and is developing "T-cell booster" peptides designed to amplify immune responses in cancers and other immune diseases where current therapies fail. The company's initial focus is on gastrointestinal and gynecologic cancers, with an expanding pipeline in autoimmunity.