SAN CARLOS, Calif. — September 9, 2026
TwoStep Therapeutics announced an oversubscribed $62.5 million Series A financing alongside U.S. Food and Drug Administration (FDA) clearance of the company’s Investigational New Drug (IND) application for TS-104, its lead multi-specific peptide-drug conjugate (PDC). The IND clearance enables TwoStep to initiate a first-in-human Phase 1 clinical trial, with patient enrollment expected to begin later in 2026. The financing was led by Insight Partners and Medical Excellence Capital, with M Ventures and Pfizer Ventures joining as co-lead investors alongside existing backers NFX and 2048 Ventures. Stanford University and additional investors also participated, bringing TwoStep’s total capital raised to $71.2 million. The financing and regulatory milestone mark a significant transition for the company from platform development into clinical-stage oncology, while also providing capital to advance its radioligand program and develop next-generation peptide conjugates.
TS-104 Targets Heterogeneous Solid Tumors
TS-104 is designed to address a key limitation of conventional tumor-targeted therapies: heterogeneous expression of individual cell-surface targets. TwoStep’s platform uses a polyspecific integrin-binding peptide (PIP) as its targeting component rather than relying on a single tumor antigen. PIP is a small synthetic peptide designed to bind five tumor-associated integrins that are expressed across a broad range of solid tumors. By engaging multiple targets, the approach is intended to provide broader tumor recognition across different tumor types, patients and individual tumor cells, potentially reducing the limitations associated with target-low or target-negative populations. The targeting scaffold also offers properties that TwoStep believes are suited to drug delivery, including small molecular size, rapid internalization and flexible conjugation chemistry. The company has coupled PIP with the clinically validated cytotoxic payload MMAE to create TS-104, establishing the lead program for clinical evaluation of its multi-specific targeting strategy.e.
Series A Supports Clinical and Platform Expansion
The $62.5 million financing provides TwoStep with resources to advance TS-104 through early clinical development while expanding its broader targeted-therapy pipeline. The company plans to use the proceeds to support the Phase 1 program and advance its radioligand therapy program, while also exploring next-generation peptide-drug conjugates. The investor syndicate brings strategic and biotechnology expertise from Insight Partners, Medical Excellence Capital, M Ventures and Pfizer Ventures, alongside the company’s existing investors. The financing also expands TwoStep’s Board of Directors, with new appointments including representatives from the lead and co-lead investors. The company was founded in 2024 around scientific work developed at Stanford University, with Caitlyn Miller, PhD, serving as co-founder and CEO alongside Stanford faculty Jennifer Cochran, Nobel laureate Carolyn Bertozzi and Ronald Levy. The combination of institutional financing, academic science and FDA IND clearance provides a foundation for transitioning the PIP platform into human clinical testing
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TwoStep Builds Multi-Specific Precision Oncology Pipeline
The entry of TS-104 into clinical development establishes TwoStep Therapeutics’ PIP platform as the foundation for a broader precision oncology strategy. Unlike approaches dependent on one highly expressed antigen, the company’s polyspecific targeting architecture is intended to expand the potential reach of targeted therapies across heterogeneous solid tumors. The modular nature of PIP allows the same targeting scaffold to be paired with different therapeutic payloads, supporting development across cytotoxic drug delivery and radioligand therapy. The upcoming Phase 1 study will provide the first clinical assessment of whether multi-specific integrin targeting can translate into meaningful tumor delivery and therapeutic activity in patients. At the same time, the Series A financing gives TwoStep the ability to pursue additional pipeline opportunities beyond its lead asset. With $71.2 million in total capital raised and an FDA-cleared IND for TS-104, TwoStep is moving from platform validation toward clinical proof-of-concept while positioning its multi-targeting technology for broader solid-tumor applications.
Source: TwoStep Therapeutics, press release
