A Nationwide Evaluation of Bevacizumab-based Treatments in Paediatric Low-Grade Glioma in the UK: Safety. Efficacy, Visual Morbidity and Outcomes.

Overview

abstract

BACKGROUND: Bevacizumab is increasingly used in children with Paediatric Low-Grade Glioma (PLGG) despite limited evidence. A nationwide UK service evaluation was conducted to provide larger cohort 'real life' safety and efficacy data including functional visual outcomes. METHODS: Children receiving Bevacizumab-based treatments (BBT) for PLGG (2009-2020) from 11 centres were included. Standardised neuro-radiological (RANO-LGG) and visual (logMAR visual acuity) criteria were used to assess clinical-radiological correlation, survival outcomes and multivariate prognostic analysis. RESULTS: Eighty-eight children with PLGG received BBT either as 3 rd line with Irinotecan (85%) or alongside 1 st/2 nd line chemotherapies (15%). Toxicity was limited and minimal. Partial response (PR, 40%), stable disease (SD, 49%), and progressive disease (PD, 11%) were seen during BBT. However, 65% progressed at 8 months (median) from BBT cessation, leading to a radiology-based 3yr-progression-free survival (PFS) of 29%. Diencephalic syndrome (p= 0.03) was associated with adverse PFS. Pre-existing visual morbidity included unilateral (25%) or bilateral (11%) blindness. Improvement (29%) or stabilisation (49%) of visual acuity were achieved, more often in patients' best eyes. Vision deteriorated during BBT in 14 (22%), with 3-year visual-PFS of 53%; more often in patients' worst eyes. A superior visual outcome (p=0.023) was seen in Neurofibromatosis type 1-associated Optic Pathway Glioma (OPG). Concordance between visual and radiological responses was 36%; optimised to 48% using only best eye responses. CONCLUSIONS: BBTs provide effective short-term PLGG control and delay further progression, with a better sustained visual (best >worst eye) than radiological response. Further research could optimise the role of BBTs towards a potentially sight-saving strategy in OPG.