CAMBRIDGE, Mass. — Parabilis Medicines, led by chairman and CEO Dr. Mathai Mammen, has raised $305 million in an oversubscribed Series F financing to accelerate the clinical development of its lead cancer therapy zolucatetide (FOG-001) and expand its proprietary Helicon peptide platform, the company said.
The financing round was co-led by RA Capital Management, Fidelity Management & Research Company, and Janus Henderson Investors, with new participation from Frazier Life Sciences, Soleus Capital, and a life sciences-focused investment fund. A broad group of existing investors also joined the round, which was completed at a higher valuation than Parabilis’s previous financing.
Parabilis said proceeds from the funding will be used to advance zolucatetide, a first-in-class Helicon peptide designed to directly inhibit the β-catenin:TCF interaction, a critical driver of the Wnt/β-catenin signaling pathway. The drug is being developed across multiple tumor types, including progression toward a registrational trial in desmoid tumors, as well as continued evaluation in both genetically simple and biologically complex cancers.
The financing will also support the company’s broader discovery pipeline, including prostate cancer programs, and further expansion of the Helicon platform, which targets disease-driving proteins long considered undruggable.
“Our goal at Parabilis is to develop medicines with the potential to deliver truly life-changing impact for patients who urgently need new treatment options,” said Mammen, who serves as chairman, chief executive officer, and president. “This support enables us to advance zolucatetide across a range of rare and common tumor types while continuing to build a differentiated pipeline through our Helicon platform.”
The funding follows the presentation of preliminary data in the fourth quarter of 2025 from an ongoing Phase 1/2 clinical trial of zolucatetide. The trial targets the Wnt/β-catenin pathway, which is implicated in millions of cancer cases annually but is not addressed by any currently approved therapies.
Early clinical results showed single-agent activity across several low-complexity tumor types driven by Wnt/β-catenin alterations, including desmoid tumors, which have received Fast Track designation from the U.S. Food and Drug Administration, and adamantinomatous craniopharyngioma. The data also supported the rationale for combination approaches in more complex cancers such as microsatellite-stable colorectal cancer.
Parabilis said it plans to present additional data on desmoid tumors and early clinical signals in hepatocellular carcinoma and familial adenomatous polyposis, with further updates expected in 2026.
Beyond zolucatetide, the company highlighted continued progress across its Helicon platform, citing encouraging preclinical results from degrader programs targeting ERG and allosteric ARON, two historically difficult targets in prostate cancer.
“Successfully drugging a target long considered undruggable requires both deep biological insight and a differentiated technological approach,” said Jake Simson, partner at RA Capital. “With Helicons, Parabilis has established a platform with the potential to generate a robust pipeline of impactful therapies.”
Parabilis’s Helicon peptides are engineered to selectively engage intracellular disease-driving targets that are inaccessible to antibodies and poorly suited to traditional small-molecule drugs, offering a new strategy to address large portions of the human proteome previously beyond the reach of existing therapies.
