Strand Therapeutics has closed a $153 million Series B financing round to accelerate development of its programmable mRNA therapeutic platform, bringing the biotechnology company’s total funding to more than $250 million. The round was led by Kinnevik, with participation from new investors including Regeneron Ventures, ICONIQ, and Amgen Ventures.
The Cambridge-based company’s funding announcement comes alongside promising early clinical data from its lead program, STX-001, which targets solid tumors through localized delivery of interleukin-12 (IL-12). Initial Phase 1 results presented at the 2025 ASCO Annual Meeting showed multiple RECIST responses, including complete responses and prolonged disease stabilization in treatment-resistant patients.
Clinical Validation Drives Investor Interest
STX-001 represents a departure from traditional mRNA therapies by utilizing self-replicating mRNA designed to express IL-12 directly within tumor microenvironments. This approach aims to reprogram immune responses while maintaining localized therapeutic activity. The therapy demonstrated systemic immune activation and anti-tumor responses across multiple tumor types, including responses in non-injected lesions.
“We believe programmable RNA is the next frontier in therapeutics, and Strand has built the leading platform to unlock it” said Christian Scherrer, Senior Investment Director at Kinnevik, who will join Strand’s board of directors as part of the financing.
Platform Technology Addresses Delivery Challenges
Beyond its lead program, Strand Therapeutics has advanced STX-003, described as the first systemically administrable mRNA therapy with tumor targeting capabilities. Preclinical data presented at 2025 AACR and ASGCT meetings demonstrated the candidate’s ability to target IL-12 expression to tumors following systemic administration while avoiding off-target delivery to organs like the liver.
The company’s proprietary platform combines engineered mRNA modalities with genetically programmed logic circuits, enabling controlled therapeutic payload delivery directly into target cells and tissues. This technology foundation differentiates Strand from other mRNA developers by addressing key challenges around specificity and safety.
Expansion Plans and Pipeline Development
The Series B funding will support expansion of Strand’s existing clinical programs while advancing breakthrough pipeline assets. CEO and co-founder Jacob Becraft emphasized the company’s mission to serve patients with limited treatment options through programmable genetic medicines.
“With support from our investors, we’re advancing our vision of developing safe, effective, and accessible therapies through programmable genetic medicines, especially for those patients with few treatment options” Becraft stated.
IL-12, the cytokine targeted by both STX-001 and STX-003, is produced by immune cells including macrophages and dendritic cells. Its potent immunostimulatory properties have made it a target of interest for cancer immunotherapy, though delivery challenges have historically limited its therapeutic application.
The investment syndicate includes both new and returning participants, with existing investors FPV Ventures, Playground Global, Eli Lilly and Company, ANRI, and Potentum continuing their support. New participants beyond those mentioned include Alderline Group, JIC-VGI, LG Technology Ventures, and Gradiant Corporation.