Efficacy and safety of apatinib for patients with advanced extremity desmoid fibromatosis: a retrospective study

Desmoid fibromatosis (DF) is a locally aggressive connective-tissue tumor arising in deep soft tissues. Although multiple therapeutic modalities have been demonstrated effective for DF, there is no standard systemic treatment for progressive and recurrent DF. As a part of systemic treatment, tyrosine kinase inhibitors have shown promising activity against DF with tolerable toxicity profiles. Thus, the aim of this study was to investigate the efficacy and safety of apatinib, a novel multi-target angiogenesis inhibitor, in patients with DF. We retrospectively analyzed the medical records of patients with advanced extremity DF regularly treated with apatinib between October 2017 and January 2020 in our center. Apatinib was initially administered with a dose of 250 mg daily and the dose was adjusted according to the toxicity. Tumor response was assessed by the Response Evaluation Criteria in Solid Tumors 1.1 criteria. The primary endpoint was progression-free survival (PFS); objective response rates and drug-related adverse events were also evaluated. A total of 22 (6 male, 16 female) patients with advanced extremity DF were included. The mean medication time was 17 months. None of the patients reached a complete response, but ten (45.5%) patients achieved partial response, and 11 patients (50%) achieved stable disease. One (4.5%) patient developed progressive disease, and the 1-year PFS rate was 95.2%. The disease control rate was 95.4% (21/22) and the objective response rate was 45.5% (10/22). Meanwhile, 18 (81.8%) patients with a tumor shrinkage were accompanied by a decreased signal intensity of lesions in T2-weighted magnetic resonance imaging. The most frequent adverse events included hand-foot syndrome (n = 7, 31.8%), fatigue (n = 6, 27.2%), local pain (n = 4, 18.1%), diarrhea (n = 4, 18.1%). Apatinib is an effective and well-tolerated option for patients with advanced extremity DF. Indeed, further prospective, randomized studies with larger cases are required to fully explore the clinical utility of apatinib in DF.