Promising results from a phase 3 trial could represent a paradigm shift in treatment of patients with desmoid tumors, say National Cancer Institute (NCI) researchers. Sorafenib tosylate extended progression-free survival (PFS) compared with that of placebo in 87 patients with desmoid tumors or aggressive fibromatosis (DT/DF).
Desmoid tumors or aggressive fibromatosis are rare sarcomas, usually found in the extremities or the abdomen and occasionally associated with familial adenomatous polyposis or Gardner syndrome. Effectiveness of current treatments—surgery, radiation, chemotherapy—is generally limited, says Jeff Abrams, MD, clinical director of NCI’s Division of Cancer Treatment and Diagnosis.
Sorafenib is a targeted treatment that interferes with the growth of cancer cells and new blood vessels that feed the tumors. It is approved for some patients with advanced kidney, liver, and thyroid cancers. It was chosen for the NCI trial because in earlier studies DT shrank in patients on sorafenib, and patients had fewer symptoms, including less pain.
Patients were assigned to receive sorafenib 400 mg/d or placebo. The trial was designed to assess improvement in PFS from 6 months for placebo to 15 months for sorafenib. Based on an interim analysis of the first 75 patients enrolled, the observed improvement in PFS exceeded the target. Patients on sorafenib were more likely to experience drug-related adverse effects, but those were generally not severe.
Treatment assignments have been disclosed to patients still receiving treatment and their physicians. Those who were receiving sorafenib can continue therapy, and those on placebo can switch to sorafenib.