Abstract 306P
Background
Angiogenesis is one of the most distinctive hallmarks of glioblastoma (GBM). The aim of this study is to assess the difference in terms of survival and safety between the 5mg/m2 and 10mg/m2 bevacizumab schedule in recurrent GBM.
Methods
All pts treated at Veneto Institute of Oncology from May 2013 to March 2022 were retrospectively reviewed. Major inclusion criteria were: histologically confirmed diagnosis of IDHwt GBM/IDHmut grade 4 astrocytoma, relapse after first or subsequent line of therapy, treatment with bevacizumab at 5mg/m2 or/and 10mg/m2 at physician’s discretion every 2 weeks.
Results
81 pts were enrolled. mFollowup was 10.9ms [95% CI 9.8-14.0], mAge was 53ys (range 18-81). 33pts (41%) received the 5mg/m2 schedule: 2 (6%) were IDHmut grade 4, 8 (24%) had ≥65ys and ECOG-PS was 0-1 in 16 (48%) and ≥2 in 17 (51%) respectively. MGMT was methylated in 15 of 30 (50%) evaluable pts. mNumber of prior lines of therapy was 2 (range 1-4) and 30% of pts received bevacizumab at first relapse. 28pts (84%) were evaluable for response: 7 (21%) and 5 (15%) showed PR and SD. 48pts received the 10mg/m2 schedule: 5 (10%) were IDHmut grade 4 astrocytoma; 29 (60%) had an ECOG-PS of 0-1 and 4 (8%) had ≥65ys, MGMT was methylated in 20 of 44 (45%) evaluable pts. 36pts (75%) received bevacizumab beyond the second line of therapy. 46pts (96%) were evaluable for response: 6 (12%) had PR, 19 (39%) SD. mOS from bevacizumab start was 7.3ms (95% CI 4.3-6.4), mPFS was 4.4ms [95% CI 3.7 – 6.4]. At univariate analysis, pts who received the 5 mg/m2 or the 10 mg/m2 schedule had a mOS of 5.4 and 7.7ms (p=0.08); mOS for pts with ECOG-PS < or ≥2 was 9.0 and 5.4ms (p=0.04), mOS for pts with <2 or ≥2 lines of therapy was 4.7 and 7.7ms (p=0.056). At multivariate analysis, MGMT methylated status was the only factor associated with OS (HR=0.48, 95% CI, p=0.002) and PFS (HR=0.33, 95% CI, p=0.001), while a number of prior lines of therapy ≥2 (HR=2.07, 95% CI, p=0.02) was associated only with PFS. Grade 3-4 most common AE were hypertension (18%) in pts treated with 5mg/m2 and hypertension (16%) and proteinuria (2%) in pts treated with 10mg/m2.
Conclusions
Bevacizumab at 5mg/m2 and 10mg/m2 seems to give comparable outcome in terms of survival in recurrent GBM. No difference was demonstrated for safety.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.