OBJECTIVE: To investigate the question of whether salvage therapy with the 
programmed cell death protein 1 (PD-1)-blocking antibodies nivolumab or 
pembrolizumab with or without bevacizumab offers clinical or survival benefit in 
patients with recurrent high-grade gliomas (HGGs).
METHODS: This was a single-institution retrospective observational study in 31 
adult patients who received pembrolizumab (Keytruda) or nivolumab (Opdivo) with 
or without concurrent bevacizumab for recurrent high-grade glioma.
RESULTS: Median progression-free survival (mPFS) from first anti-PD-1 dose was 
3.2 months (95% confidence interval [CI] 2.2-4.2), and there was no difference 
in patients receiving nivolumab (mPFS 3.8 months, 95% CI 1.7-5.8) compared to 
patients receiving pembrolizumab (mPFS 2.3 months, 95% CI 1.7-2.8, log rank 3.1, 
p = 0.08). There was also no difference in mPFS if patients had previously 
received bevacizumab (mPFS 3.2 months, 95% CI 2-4.3) or were bevacizumab naive 
(mPFS 3.7, 95% CI 0-7.9, log rank 1.3, p = 0.3). The median survival from date 
of first anti-PD-1 dose was 6.6 months (95% CI 4.2-9.1).
CONCLUSION: Salvage therapy with nivolumab or pembrolizumab with or without 
bevacizumab does not confer a survival benefit in this heavily pretreated 
unselected patient population. Until the results of the currently ongoing 
clinical trials become available, the use of PD-1-blocking antibodies should be 
considered in selected individuals only.
CLASSIFICATION OF EVIDENCE: This retrospective observational study provides 
Class IV evidence that for patients with recurrent HGGs, salvage therapy with 
nivolumab or pembrolizumab does not significantly improve survival.