5 and Supplementary Table 8). Efficacy of the IDH1-vac The overall response rate was 84.4% (95% CI 67.21–94.72%, 27 of 32 patients) of the SDS, corresponding to 86.7% (95% CI 69.28–96.24%, 26 of 30 patients) of the IDS at the end of study (EOS; Fig. 3a, Extended Data Fig. 6). In followup analyses of the SDS, three-year progression-free and death-free rates were 0.63 (95% CI 0.44–0.77) and 0.84 (95% CI 0.67–0.93), respectively. Two patients of the IDS (ID05 and ID30) who did not mount an IDH1-vac induced immune response (Extended Data Fig. 3) showed progression within two years, compared to patients with immune responses (two-year progression-free rate of 0.82 (95% CI 0.623–0.921) in patients with immune responses; Fig. 3b). IDH1-specific T cell responses and pseudoprogression In the SDS, pseudoprogression (PsPD) occurred in 12 of 32 patients (37.5%) compared to 10 of 60 (16.7%) in a molecularly matched control cohort (Supplementary Table 3). Contrast-enhancing PsPD diagnosed by brain imaging is indicative of intratumoral inflammatory reactions (Fig. 3c). There was no apparent association with age, extent of resec- tion, SOC treatment, or WHO grade. The longer median observation period (7.3 years) in the matched cohort caused a bias towards the detection of more PsPD. In NOA16, PsPD was associated with the onset of peripheral IDH1-vac-induced immune responses (Extended Data Fig. 7) and was restricted to patients with transient or sustained T cell immune responses; we did not detect PsPD in non-responder patients (Fig. 3d).