Anorexia, Hypertension, Pneumothorax, and Hypothyroidism: Potential Signs of Improved Clinical Outcome Following Apatinib in Advanced Osteosarcoma

AIM: Apatinib, a specific tyrosine kinase inhibitor (TKI) that targets mainly vascular endothelial growth factor receptor-2 (VEGFR-2) as well as Ret, c-Kit and c-Src, has been assessed in patients with advanced osteosarcoma (phase II), the primary report of which has been published in PMID 30559126. This sub-study explored the potential signs of Adverse Events (AEs) for apatinib-treated osteosarcoma. METHODS: Participants with advanced osteosarcoma progressing upon chemotherapy received apatinib until disease progression or unacceptable toxicity. Toxicities, progression-free survival (PFS), and clinical benefit rate (CBR) following treatment were evaluated. RESULTS: Of the 41 patients recruited to the study, 37 received treatment and constituted the safety population. At data cut-off (December 30, 2017), median follow-up for safety was 7.37 (IQR, 6.33–11.07) months. The most common grade 3–4 AEs were pneumothorax (16.22%), wound dehiscence (10.81%), proteinuria (8.11%), diarrhea (8.11%), and skin reaction (8.11%). Only hypertension was an independent predictive factor for both PFS (hazard ratio [HR], 0.44; P = 0.07) and CBR (P = 0.07). Anorexia was also significantly related to a longer PFS in a Cox regression model (HR, 0.35; P =0.01). For CBR, pneumothorax and hypothyroidism showed more clinical benefit (P = 0.07 and 0.00, respectively). CONCLUSION: The results of this study suggest that anorexia, hypertension, pneumothorax, and hypothyroidism might be markers for a favorable clinical outcome following apatinib-treated refractory osteosarcoma.