Abstract 371P
Background
Focal radiation necrosis of the brain (fRNB) is an adverse event (AE) following the treatment of benign or malignant brain lesions with stereotactic radiation therapy (SRT) or stereotactic radiosurgery (SRS). An increased incidence of fRNB has been reported in cancer patients (pts) treated with immune checkpoint inhibitors. Bevacizumab (BEV), a vascular endothelial growth factor-neutralizing monocolonal antibody, has shown to be an effective treatment for fRNB at a dose of 5-7.5 mg/kg Q2W x4. Based on pharmacokinetic/-dynamic data, a “low-dose regimen” of BEV (400 mg loading dose followed by 100 mg Q4W) was investigated in pts diagnosed with fRNB.
Methods
Clinical outcome data on all pts who received low-dose BEV for the treatment of fRNB at our center were retrospectively collected.
Results
Between March 2016 and December 2020, 10 pts (6 male, 4 female; median age 50 (range 31-68)) started treatment with low-dose BEV for fRNB. SRS/SRT had been administered for brain metastases from melanoma (5 pts), non-small cell lung cancer (2 pts), renal cell carcinoma (1 pt), medulloblastoma (1 pt), or arteriovenous malformation (1 pt). Three pts had previously been treated with and responded well to the BEV standard dosing regimen, but suffered a recurrence of fRNB after stopping BEV administrations. One pt did not receive a loading dose. All 10 pts had a marked improvement in clinical symptoms and magnetic resonance imaging (MRI) abnormalities. In the 3 pts who had previously been treated with the standard dose regimen of BEV, the response to the low-dose BEV regimen was identical. One pt with therapy-resistant partial epilepsy experienced a complete resolution of seizure activity after initiating treatment. There were no severe AE related to the BEV treatment. In 3 pts BEV was stopped after obtaining a maximal clinical and radiological response, but had to be resumed at the time of relapse of symptoms and MRI abnormalities. At the time of this report, 3 pts are on treatment with low-dose BEV and 7 pts are off-therapy with a remission of their fRNB. All pts treated with the low-dose regimen were alive at latest follow-up.
Conclusions
Treatment of fRNB with a low-dose regimen of BEV is an effective and cost-lowering alternative for standard-dose BEV.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
J.K. Schwarze: Non-Financial Interests, Personal, Other: MSD Oncology; Non-Financial Interests, Personal, Other: Amgen; Financial Interests, Personal, Invited Speaker: Novartis. G. Awada: Financial Interests, Personal, Invited Speaker: Novartis; Non-Financial Interests, Personal, Other: MSD; Non-Financial Interests, Personal, Other: Astellas; Financial Interests, Personal, Advisory Board: Novartis. B. Neyns: Financial Interests, Personal, Invited Speaker: Roche; Financial Interests, Personal, Invited Speaker: Bristol-Myers Squibb; Financial Interests, Personal, Invited Speaker: MSD; Financial Interests, Personal, Invited Speaker: Novartis; Financial Interests, Personal, Invited Speaker: AstraZeneca; Financial Interests, Institutional, Funding: Pfizer; Financial Interests, Institutional, Funding: Novartis; Financial Interests, Institutional, Funding: Roche; Financial Interests, Institutional, Funding: MSD. All other authors have declared no conflicts of interest.