FOG-001 Receives FDA Fast Track Designation in Desmoid Tumors

The FDA has granted fast track designation to FOG-001 for the treatment of desmoid tumors.¹

The FDA’s fast track designation is intended to help facilitate the development and expedite the review of new therapies for serious conditions that address an unmet medical need. Fast track designation enables more frequent interactions with the FDA throughout development and provides eligibility features, such as rolling review and potential priority review.

“Obtaining fast track designation for FOG-001 reinforces our confidence in its potential to offer meaningful clinical benefit to patients with desmoid tumors, who today have no therapies that directly address the underlying disease biology,” said Fawzi Benzaghou, MD, chief medical officer of Parabilis Medicines, in a news release. “More than half of patients do not respond to current treatment options, which are also associated with high toxicities. By inhibiting the β-catenin:TCF [T-cell factor] interaction, FOG-001 has the potential to intervene at the source of disease and marks an important step forward in advancing our mission to drug the undruggable.”

This designation follows preliminary data first released at the 2025 European Society of Medical Oncologists Congress in October. More data will be presented at the Connective Tissue Oncology Society 2025 Annual Meeting, demonstrating that FOG-001 has clinically meaningful antitumor activity in desmoid tumors.

In an ongoing phase 1/2 trial (NCT05919264), 12 patients with desmoid tumors have been treated with FOG-001. As of the cutoff date of August 2025, tumor reductions were observed in all response-evaluable patients (n = 10), and an 80% objective response rate was observed in patients with more than 1 post-baseline scan (n = 5). No grade 4/5 treatment-related adverse events or discontinuations were reported.

The trial is testing FOG-001 as both a monotherapy and in combination with other anticancer agents in patients with advanced or metastatic solid tumors likely or known to harbor a Wnt pathway-activating mutation.

Additionally, FOG-001 is being evaluated across a broad range of rare and common Wnt/β-catenin-driven tumor types. Clinical data presented at the AACR-NCI-EORTC 2025 meeting showed FOG-001 had single-agent activity in 5 low-complexity tumor types where Wnt/β-catenin mutations are the primary drivers of the disease.² 

“The Wnt/β-catenin pathway is implicated in millions of cancer cases each year, yet remains unaddressed by approved therapies despite decades of effort,” said Mathai Mammen, MD, PhD, chairman and CEO of Parabilis Medicines, in a news release.¹ “FOG-001 demonstrates that our Helicon peptides can unlock disease biology once considered completely inaccessible—opening a new path to drug targets long though out of reach and medicines with the potential to fundamentally transform outcomes for patients.”

FOG-001 is an investigational first-in-class competitive inhibitor of β-catenin interactions with the TCF family of transcription factors and is currently in clinical development. FOG-001 is intended to block the Wnt signaling pathway irrespective of the various APC and β-catenin mutations that typically drive disease.

Parabilis Medicines plans to share additional FOG-001 data in 2026.

REFERENCES

1. Parabilis Medicines receives FDA fast track designation for FOG-001, the first and only direct inhibitor of the β-catenin:TCF interaction, for the treatment of desmoid tumors. News release. Parabilis Medicines. November 13, 2025. https://tinyurl.com/54maaz9a 

2.Parabilis Medicines presents clinical and preclinical data demonstrating broad potential of Helicon peptides at AACR-NCI-EORTC 2025. News release. Parabilis Medicines. Published October 24, 2025. Accessed November 13, 2025. https://tinyurl.com/3vpzhn5u