Stanford spinout TwoStep raises $62.5M to tackle ADC challenges

TwoStep Therapeutics, a biotech emerging from Stanford, has closed a $62.5 million Series A to advance its work on antibody-drug conjugate (ADC) tumor penetration and toxicity. The round, reported by *note.com*, also includes the first mention of its lead program, TS-104, a preclinical compound described as a peptide-based therapy aimed at improving on current ADC designs.

The funding arrives as the ADC field faces growing scrutiny over its constraints. Clinicians have pointed to issues like limited penetration into solid tumors and off-target effects, which can narrow the therapeutic window. TwoStep’s approach centers on using peptides to potentially enhance delivery while reducing toxicity. If successful, this could broaden ADC applications beyond their current stronghold in hematologic cancers. If not, the company risks becoming another entrant in a crowded space trying to refine the same core challenges.

What stands out about this round isn’t just the amount—$62.5 million is substantial but not exceptional in today’s biotech market—but the context. TwoStep is entering a sector where differentiation is increasingly critical. Recent large raises, like Enveda’s $311 million Series E, highlight how AI-driven drug discovery is becoming a baseline expectation for biotechs seeking significant funding. TwoStep isn’t positioning itself as an AI-first company, but it’s wagering that its peptide-based platform can achieve what other approaches haven’t: solving the delivery problem. This is a gamble, given that peptides come with their own complexities, such as rapid clearance and potential immune responses.

The company’s connection to Stanford may play a role in its appeal. TwoStep’s scientific founder has a background in chemistry that has previously influenced linker technology, which could have helped attract investors. However, this also raises expectations. Backers will likely look for evidence that TS-104 can demonstrate meaningful advantages over existing therapies, not just incremental progress.

One gap in the current reporting is the lack of detail about TwoStep’s broader pipeline beyond TS-104. The Series A suggests the company is still in early development, meaning human data could be at least a year away. That’s a lengthy timeline in a competitive space where other companies are already advancing clinical-stage ADC platforms. TwoStep’s peptide approach could set it apart, but peptides have historically faced hurdles in oncology due to stability and delivery issues. Without compelling preclinical data soon, the $62.5 million raise might start to feel like an uphill battle.

The round also prompts questions about the broader ADC investment trend. While some biotech funding is flowing into alternative platforms, like Typewriter’s $56 million Series A for non-viral gene therapy, TwoStep’s raise indicates continued interest in companies that can address ADC limitations. The key for investors will be whether these companies can move beyond vague promises of "better" and provide concrete evidence of improvement. TwoStep’s focus on tumor penetration and toxicity is a step toward specificity, but the real test will be whether its data can deliver on that promise.

For now, the story reflects the ADC sector’s broader dynamics: high potential, high uncertainty, and a widening divide between a few standout successes and many others struggling to carve out a niche. TwoStep has the backing and the narrative, but in biotech, those only go so far. The next critical milestone won’t be another funding announcement—it’ll be whether TS-104 can show progress where others haven’t.

Sources: note.com