In this article
FDA Approval of Nirogacestat for Desmoid Tumors
The Food and Drug Administration authorized nirogacestat (OGSIVEO, SpringWorks Therapeutics, Inc.) on November 27, 2023, for adult patients with advancing desmoid tumors needing systemic treatment. This is the initial authorized therapy for desmoid tumors.
DeFi Clinical Trial and Efficacy Analysis
A study called DeFi (NCT03785964) looked at how well it worked. It was an international, multicenter, randomized (1:1), double-blind, placebo-controlled experiment with 142 patients who had desmoid tumors that were getting worse and could not be treated with surgery. Patients were qualified if the desmoid tumor had advanced within 12 months after screening. Participants were randomly assigned to take 150 mg of nirogacestat or a placebo orally twice a day until illness progression or intolerable toxicity.
Progression-free survival (PFS) calculated by RECIST v1.1 by a blinded independent central review or clinical progression assessed by the investigator and reviewed independently was the main way to measure how well the treatment worked. The median progression-free survival (PFS) was not determined in the nirogacestat group (95% CI: not determined) and was 15.1 months (95% CI: 8.4, not determined) in the placebo group. The hazard ratio (HR) was 0.29 (95% CI: 0.15, 0.55) with a p-value of less than 0.001. An initial investigation of progression-free survival (PFS) using solely radiographic progression revealed a hazard ratio of 0.31 (95% CI: 0.16, 0.62).
Objective Response Rate and Pain Management
The objective reaction rate (ORR) was an extra measure of effectiveness. The Objective Response Rate (ORR) was 41% (95% CI: 29.8, 53.8) for participants in the nirogacestat group and 8% (95% CI: 3.1, 17.3) for those in the placebo group (p-value=<0.001). The improvement in patient-reported worst pain from the beginning of the study, which favored the nirogacestat group, further confirmed the efficacy results.
Side Effects and Adverse Reactions
The prevalent adverse effects included diarrhea, ovarian toxicity, rash, nausea, exhaustion, stomatitis, headache, stomach discomfort, cough, alopecia, upper respiratory tract infection, and dyspnea.
Recommended Dosage and Administration
The suggested nirogacestat dosage is 150 mg taken twice a day orally, with or without food, until illness progresses or there is unacceptable toxicity. Each dose of 150 mg comprises three 50 mg pills.
View full prescribing information for OGSIVEO.
How CancerFax Helps
CancerFax is a specialist cancer access and patient-navigation platform. We help patients and families understand their options, organise medical records, coordinate hospital communication, and support cross-border treatment planning where appropriate.
We help collect and organise reports, scans, pathology, biomarker results, and treatment history for structured case review.
We communicate with hospitals or trial teams to assess whether a case may be suitable for further screening.
We support appointment coordination, document submission, translation, and direct communication with international departments.
For international patients, we help with practical coordination — travel planning, hospital admission guidance, and local support.
If this option is not suitable, we help explore other relevant treatments, clinical trials, or advanced care pathways.
From inquiry through to follow-up, our coordinators provide a single point of contact for the family.
CancerFax does not guarantee treatment access, eligibility, or clinical outcome. Our role is to help patients access accurate information, structured review, and appropriate specialist pathways.

About Susan Hau
Susan Hau is a distinguished researcher in the field of cancer cell therapy, with a particular focus on T cell-based approaches and cancer vaccines. Her work spans several innovative treatment modalities, including CAR T-cell therapy, TIL (Tumor-Infiltrating Lymphocyte) therapy, and NK (Natural Killer) cell therapy. Hau's expertise lies in cancer cell biolo…
✓ Reviewed for medical accuracy by the CancerFax review panel.
Medical Disclaimer
This article is for educational purposes only and should not replace medical advice, diagnosis, or treatment from a qualified oncology specialist. Every patient's case is different. Treatment decisions should always be made after a review of complete medical records by the treating medical team.
Treatment availability, eligibility, timelines, and access can change. Any clinical trial participation depends on detailed review and approval by the trial hospital or investigator.
