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

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.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.

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).

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.