Parabilis Medicines raises $305M Series F for cancer programs

Parabilis Medicines has closed an oversubscribed $305 million Series F financing to advance its lead cancer drug candidate FOG-001 and expand its Helicon peptide platform. The round was co-led by RA Capital, Fidelity, and Janus Henderson at a higher valuation than the company’s previous financing.

Funding details: $305M USD (Series F)

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Parabilis Medicines, a Cambridge, Massachusetts–based clinical-stage biopharmaceutical company, has raised $305 million in an oversubscribed Series F financing to support the continued development of its cancer pipeline. The company is focused on targeting historically undruggable cancer drivers using its proprietary Helicon peptide platform. Parabilis Medicines operates from Cambridge and is building therapies aimed at both rare and common tumors.

The financing was co-led by RA Capital Management, Fidelity Management & Research Company, and Janus Henderson Investors. New investors joining the round include Frazier Life Sciences, Soleus Capital, and a life science–dedicated investment fund. Existing investors also participated heavily, including venBio Partners, Cormorant Asset Management, ARCH Venture Partners, GV, General Catalyst, Invus, and Foresite Capital, among others. The round was completed at an increased valuation compared to Parabilis’s prior financing.

The new capital will primarily support clinical development of FOG-001, also known as zolucatetide, Parabilis’s lead investigational therapy and the first direct inhibitor of the β-catenin and TCF interaction. The company plans to progress the drug toward a registrational trial in desmoid tumors while continuing evaluation across a broader range of genetically simple and complex tumor types. Funding will also be used to advance Parabilis’s discovery pipeline, including its prostate cancer programs, and to further expand the capabilities of its Helicon platform.

Parabilis Chairman, CEO, and President Mathai Mammen said the financing strengthens the company’s ability to advance zolucatetide across multiple tumor types while continuing to build a differentiated pipeline aimed at biology that has remained out of reach for decades. Investors echoed this view, noting that Parabilis’s Helicon technology offers a new way to address intracellular targets that traditional drug approaches have failed to reach.

The financing follows encouraging preliminary data presented in late 2025 from an ongoing Phase 1/2 trial of zolucatetide. Early results showed single-agent activity across several Wnt/β-catenin–driven tumor types, including desmoid tumors, which have received Fast Track designation from the U.S. Food and Drug Administration. Parabilis plans to share additional clinical data in 2026 while continuing to expand the application of its Helicon platform beyond its lead program.