Desmoid tumors, also called aggressive fibromatosis, are rare locally-invasive mesenchymal tumors driven primarily by aberrant activation of the Wnt/beta-catenin signaling pathway, either through somatic CTNNB1 mutations in sporadic cases or germline APC mutations in patients with familial adenomatous polyposis. They do not metastasize, but recurrent local growth can encase nerves, vessels, and viscera, and surgery alone fails in a substantial share of patients.
The approved targeted option is nirogacestat (Ogsiveo) from SpringWorks Therapeutics, a gamma-secretase inhibitor cleared by the FDA in 2023, with sorafenib also used off-label. The peptide modality is now entering the field through Parabilis Medicines's zolucatetide, a cell-penetrating helical peptide that blocks beta-catenin directly. Public filings cite a 74% objective response rate in a 19-patient desmoid-tumor cohort behind dose expansion. Parabilis plans a Phase 3 in the first half of 2027, funded by a June 10, 2026 upsized $670 million IPO that set the venture-backed biotech record.
Stories here cover desmoid-tumor program readouts and the Wnt-pathway competitive set. See [[zolucatetide]], [[parabilis-medicines]], and [[helical-peptide]] for adjacent threads.
Parabilis Medicines (Nasdaq: PBLS) opened June 10 at $33.35 and closed at $31.60 on its Nasdaq debut, a 58% first-day gain after pricing an upsized $670 million IPO at $20 per share — above the previously announced $17-19 range and well past the $476 million initial target Parabilis set on June 4. The 33.5 million-share offering breaks the venture-backed biotech IPO record. Proceeds extend runway for the lead asset zolucatetide, a cell-penetrating helical peptide targeting Wnt/β-catenin in cancer, with a Phase 3 in desmoid tumors expected in the first half of 2027.
Parabilis Medicines (formerly FogPharma) set terms June 4 for a Nasdaq IPO under ticker PBLS: 25 million shares at $17-19, raising about $413 million, or up to $476 million if underwriters exercise the overallotment. Proceeds fund its lead asset zolucatetide, a cell-penetrating helical peptide that blocks beta-catenin, through dose expansion and into Phase 3 for desmoid tumors, plus studies in familial adenomatous polyposis and hepatocellular carcinoma. The offering follows a $75 million Regeneron investment tied to a collaboration worth up to $2.3 billion for antibody-helicon conjugates.
Parabilis Medicines (formerly FogPharma) filed its S-1 on May 19 to list on Nasdaq under ticker PBLS, seeking ~$100M to fund Phase 3 of zolucatetide (FOG-001), a stabilized helical peptide and the first direct inhibitor of the β-catenin:TCF interaction. As of February 16, 38 desmoid-tumor patients were dosed; 25 had sufficient follow-up to be response-evaluable, all showed tumor reduction, and 74% of the 19 patients with ≥2 post-baseline scans hit RECIST 1.1 objective response. The IPO follows a $305M Series F in January and a Regeneron research deal worth up to $2B. FDA granted fast track designation for desmoid tumors.