BACKGROUND: Results of our previous study showed high objective response but 
short-term activity of apatinib in advanced osteosarcoma. We aimed to 
investigate the activity of apatinib in combination with camrelizumab in 
patients with inoperable high-grade osteosarcoma progressing after chemotherapy.
METHODS: This open-label, phase 2 trial was conducted at Peking University 
People's Hospital. We enrolled patients with advanced osteosarcoma progressed 
after chemotherapy. Patients received 500 mg apatinib orally once daily plus 
200 mg camrelizumab by intravenous infusion every 2 weeks until disease 
progression or unacceptable toxicity. The primary endpoint was progression-free 
survival (PFS) and clinical benefit rate at 6 months, which were based on RECIST 
V.1.1.
RESULTS: 43 patients were enrolled between January 25 and September 4, 2018. 
With median follow-up time of 48.3 (Q1, Q3, 30.6, 66.6) weeks, 13 (30.23%, 
95% CI 17.2%, 40.1%) of 43 patients were progression free at 6 months and the 
6-month PFS rate was 50.9% (95% CI 34.6%, 65.0%). Until final follow-up, the 
objective response rate was 20.9% (9/43) and two patients with durable disease 
control were observed. Patients with programmed cell death 1 ligand-1 (PD-L1) 
tumor proportion score ≥5% and pulmonary metastases tended to have a longer PFS 
in comparison to the others (p=0.004 and 0.017, respectively). Toxic effects led 
to dose reductions, or interruptions, or both in 24 (55.8%) of 43 patients and 
permanent discontinuation in 4 (9.3%) patients. There were no treatment-related 
deaths.
CONCLUSIONS: Although the combination of apatinib and camrelizumab seemed to 
prolong PFS in comparison to single agent apatinib in treating advanced 
osteosarcoma, it did not reach the prespecified target of 6-month PFS of 60% or 
greater. Overexpression of PD-L1 and the presence of pulmonary metastases only 
were associated with longer PFS.
TRIAL REGISTRATION NUMBER: NCT03359018.