TwoStep Therapeutics announced a $62.5 million Series A on September 9 alongside FDA clearance to begin human testing of its lead cancer-drug candidate. The biotech is developing treatments intended to deliver a therapeutic payload to solid tumors without depending on one uniformly present target.

Many targeted therapies use a feature on cancer cells as an address. But cells within a tumor do not necessarily display the same features in the same amounts. TwoStep's approach uses a small engineered peptide—a short chain of amino acids—designed to bind five tumor-associated integrins, proteins involved in how cells interact with their surroundings.

Its first candidate, TS-104, pairs that targeting component with MMAE, a cell-killing drug payload. The intended workflow is molecular delivery: the peptide recognizes targets and helps carry the attached drug into cancer cells. This is a proposed way to broaden tumor recognition, not evidence that TS-104 already works across cancer types in patients.

The company also plans to use the same targeting component for radioligand therapies, which deliver a radioactive payload to a tumor. The reusable part is the delivery molecule, while the attached payload changes. TwoStep's science page distinguishes those programs from its lead drug-conjugate candidate, keeping the pipeline broader than a single medicine without suggesting all programs are at the same stage.

Insight Partners and Medical Excellence Capital led the financing, with M Ventures and Pfizer Ventures joining as co-leads. The company says the round brings total funding to $71.2 million. Clearance of the investigational application allows a Phase 1 trial, with enrollment expected later this year; it is not FDA approval to market the treatment.

TwoStep launched in 2024 from research developed at Stanford. The next step is to learn whether its multi-target delivery idea can produce a useful balance of tumor activity and tolerability in people. That first clinical evidence will matter more than the number of possible payloads the platform can carry.