Abstract 3P
Background
Glioblastoma (GBM) is the most common primary malignant brain tumor of adults, with an aggressive behavior and a poor prognosis associated. 90% of patients develop recurrence/progression after the first-line standard treatment with Stupp protocol. Evidence for second-line treatment remains controversial and no standard of care is established. The aim of this study was to provide real-word evidence on the use of bevacizumab plus irinotecan (BEV+IRI) as second-line treatment of GBM.
Methods
Retrospective study on adult patients with a first recurrence of a GBM, after treatment with Stupp protocol. Of these, we selected patients treated with BEV+IRI at second-line (10 mg/kg and 125 mg/m2, respectively, every 2 weeks), between 2011 and 2020, at our institution. Data were obtained from medical records. Progression-free survival (PFS) and overall survival (OS) were analyzed by the Kaplan-Meier method.
Results
42 patients were enrolled. 62% (n=26) were men and the median age was 53 years (35-78). Frontal localization of GBM was the most common (n=17, 40%). In the second-line all patients received BEV+IRI, with a mean of 19 cycles. A 20% dose reduction of IRI was necessary in 4 patients (2 cases due to severe thrombocytopenia; 2 cases due to deterioration of ECOG-PS). Response evaluation by magnetic resonance imaging revealed an objective response rate of 37% and 7%, at 3 and 6 months of treatment, respectively. There were no cases of complete response with this combination. The median PFS (mPFS) was 7 months (95% confidence interval [CI]=2.966-11.034), with a 6-month PFS of 81%. The median OS (mOS) was 8.5 months (95% CI=6.766-15.234), with a 6-month OS of 59.5%, 1-year OS of 43% and 2-year OS of 21%. The most frequent toxicities (any grade) were fatigue (n=35, 83%), diarrhea (n=26, 62%), anemia (n=23, 55%) and thrombocytopenia (n=19, 45%).
Conclusions
In this analysis mPFS and mOS were longer than the historical control group- mPFS: 7 versus 4 months (RTOG 0625); mOS: 8.5 versus 7.7 months (RTOG 0625). Toxicity profile was consistent with previously published data, but not insignificant. However, BEV+IRI is a regimen with activity in recurrent GBM and its toxicity is considered acceptable given the extremely unfavorable prognosis associated with this tumor.
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.