TwoStep Therapeutics Lands $62.5M and FDA IND Clearance for Peptide-Based ADC Alternative
- TwoStep Therapeutics, a 2024 Stanford spinout, announced an oversubscribed $62.5M Series A financing on September 10, 2026, alongside FDA clearance of the investigational new drug (IND) application for its lead candidate, TS-104.
- The round was led by Insight Partners and Medical Excellence Capital, with pharma-linked corporate venture arms M Ventures (Merck KGaA) and Pfizer Ventures co-leading; existing investors NFX, 2048 Ventures, and Stanford University also participated, bringing total funding raised to $71.2M.
- TS-104 is a first-in-class multi-specific peptide-drug conjugate (PDC) that pairs a polyspecific integrin-binding peptide, engineered to bind five tumor-associated integrins across solid tumors, with the cytotoxic payload MMAE, also used in several approved antibody-drug conjugates.
- The company positions this peptide-based platform as an alternative to antibody-based ADCs for reaching solid tumor targets.
- The IND clearance opens the way for a first-in-human Phase 1 trial, with patient enrollment expected later this year.
PDCs are pitching themselves as the cheaper, more tumor-penetrant cousin of ADCs — same MMAE payload, smaller delivery vehicle, potentially better access to solid-tumor stroma where antibodies struggle. That's a direct pitch at the ADC franchise now dominating oncology dealmaking. The investor list matters more than the dollar figure: M Ventures and Pfizer Ventures co-leading, not just writing a check, reads as two ADC-heavy pharmas hedging their own franchises and buying an early look at a modality that could either complement or cannibalize their antibody platforms. Oversubscribed Series A plus IND clearance inside two years of founding is a fast validation cycle for a still-unproven conjugate class — worth watching whether Phase 1 tolerability holds up before any partnering thesis gets real.
Exclusive: Cancer biotech TwoStep gets $62.5M to take twist on ADCs into clinic ↗