Desmoid Tumors

Desmoid tumors (DTs), also referred to as aggressive fibromatosis or desmoid-type fibromatosis, are rare and debilitating soft-tissue tumors that can occur in both children and adults. They can arise in any part of the body with the most common sites being the upper extremities (arm, forearm, and hand), lower extremities (girdle, thigh, leg, and foot), abdominal wall, thoracic areas, and head and neck. Depending on their size and location, desmoid tumors can cause severe morbidities such as pain, internal bleeding, disfigurement, and limited range of motion. In some cases, desmoid tumors can be fatal if they impact vital organs.1

Desmoid tumors are most typically diagnosed in young adults between 20-30 years of age.1 There is also a two-to-three-fold predominance in females.2 It is estimated that desmoid tumors affect 2 to 4 per million people worldwide, and that there are 900 to 1,500 new cases diagnosed each year in the United States.3 Historically, desmoid tumors were treated with surgical resection or, in severe cases, amputation, but even with these interventions, high rates of tumor regrowth have been documented.4 There are no therapies currently approved for the treatment of desmoid tumors.

Our Investigational Therapy

Nirogacestat is an investigational oral, small molecule, gamma-secretase inhibitor that has been investigated in 24 patients with desmoid tumors across Phase 1 and Phase 2 clinical trials. SpringWorks is preparing to initiate the DeFi Study, a Phase 3, double-blind, randomized, placebo-controlled, global clinical trial in patients with desmoid tumors. The United States Food and Drug Administration (FDA) granted Orphan Drug designation and Fast Track designation for nirogacestat for the treatment of desmoid tumors.

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Patient Foundation:

Desmoid Tumor Research Foundation

The mission of The Desmoid Tumor Research Foundation is to aggressively fund research to accelerate the development of improved therapies, and ultimately find a cure for desmoid tumors. The foundation collaborates with dedicated researchers and clinicians worldwide to improve the lives of patients through education, awareness, and support.


1 Gounder, M. M., Thomas, D. M., & Tap, W. D. (2017). Locally Aggressive Connective Tissue Tumors. Journal of Clinical Oncology, 36(2), 202-209. doi:10.1200/JCO.2017.75.8482.

2 Skubitz, K. M. (2017). Biology and Treatment of Aggressive Fibromatosis or Desmoid Tumor. Mayo Clinic Proceedings, 92(6), 947-964. doi:10.1016/j.mayocp.2017.02.012

3 “Desmoid Tumor.” U.S. National Library of Medicine, National Institutes of Health,

4 Scaramussa, F.S. & Castro, U. B. (2016). Desmoid Tumor in Hand: A Case Report. SM Journal of Orthopedics, 2(3),1036.