Problem

Autoimmune diseases arise when a hyperactive immune system attacks the body’s own tissues, creating persistent physical, mental, and financial burdens. The economics are substantial: the NIH says autoimmune conditions generate more than $100 billion in annual healthcare costs, while biologic treatments can cost roughly $10,000 to $500,000 per patient per year. Ditto’s core use case is to find new, potentially safer and more effective therapies for immune diseases while reducing the costly failure rate of conventional drug discovery, where billions of dollars can be wasted on candidates that never reach patients.

Product / Service

Ditto Bio is building an AI-enabled drug-discovery and protein-engineering platform based on parasite biology. It mines the genomes of viruses, ticks, and parasitic worms—organisms that have evolved for millions of years to control human immunity—then uses AI to identify drug-like proteins and engineers them into therapeutic candidates. The company says it begins with molecules that already function in humans, has identified proteins predicted to hit clinically validated targets, and is developing a tissue biobank to map immune memory and help design around immunogenicity.

The apparent delivery model is an early-stage platform and partnership business rather than a marketed drug. Ditto is seeking to work with industry immunologists, biologics developers, and protein designers by offering novel targets, natural protein scaffolds, and immunogenicity assays. The intended benefit is a new source of tightly binding protein therapeutics for autoimmune disease, with computational discovery and experimental design combined in a full design-build-test-learn cycle.

Market

Ditto competes at the intersection of autoimmune therapeutics, biologics, AI-enabled drug discovery, and computational protein engineering. Its distinctive approach is to use parasite-derived proteins as the starting point for drug discovery. The available research identifies no direct competitor, although adjacent computational drug-discovery and biotech companies such as Schrödinger, Recursion Pharmaceuticals, and Septerna are listed as possible or top competitors; these do not appear to replicate Ditto’s specific parasite-biology focus.

Ditto is an active, San Francisco-based Y Combinator Winter 2026 company founded in 2025 by three PhD scientists. Its disclosed early traction includes analyzing more than one million proteins, finding thousands predicted to engage clinically validated human targets, observing early experimental activity, and measuring binding as tight as 1–2 nM. No clinical-stage asset, customer, approved product, or revenue is disclosed in the available materials, so Ditto should be viewed as preclinical and effectively pre-revenue, despite meaningful platform-level scientific progress.