Efficacy and Safety of Apatinib for Radiation-induced Brain Injury Among Patients With Head and Neck Cancer: An Open-Label, Single-Arm, Phase 2 Study

The treatment of radiation-induced brain injury (RI) caused by radiation therapy for head and neck cancer is challenging. Antiangiogenic therapy is a promising treatment. Apatinib is an oral tyrosine kinase inhibitor that selectively inhibits vascular endothelial growth factor receptor 2. We aimed to assess the efficacy and safety of apatinib in patients with RI.In this phase 2, open-label, single-arm, prospective study, we recruited patients aged 35 to 80 years with prior radiation therapy history for head and neck cancer who had newly diagnosed RI at the Sun Yat-sen Memorial Hospital, China. Apatinib was administered at a dosage of 250 mg once daily orally for 4 weeks. A Simon minimax 2-stage design was performed. The primary outcome was the proportion of patients with overall clinical efficacy, defined as a radiographic response of ≥25% reduction in baseline brain edema volume on magnetic resonance fluid attenuated inversion recovery images at week 4. Secondary end points were the overall improvement rate of brain necrosis, neurologic function, and safety.We screened 37 patients, 36 of whom were enrolled between October 17, 2019, and August 3, 2020. At the cutoff date, 36 patients were assessed for efficacy and safety (19 were enrolled in stage 1 and 17 in stage 2). Of the 36 patients evaluated for overall clinical efficacy, 22 patients (61.1%; 95% CI, 43.5%-76.9%) achieved the primary end point at week 4. Among the 31 patients with brain necrosis lesions, 19 patients (61.3%; 95% CI, 42.2%-78.2%) showed improvement of brain necrosis. The most common grade 1 to 2 adverse events were hand-foot syndrome, fatigue, and hypertension There were no treatment-related grade 4 to 5 toxic effects.Oral apatinib shows promising efficacy and is well-tolerated in patients with RI. Further randomized controlled studies are warranted.