Lgg-18. bevacizumab: good for eyes and mri’s! a national uk assessment of visual and radiological outcomes of bevacizumab therapy in paediatric low-grade glioma (plgg)

Bevacizumab (BEV) is increasingly used for PLGGs in varying manners despite limited evidence. The potential for BEV to preserve or rescue vision in OPGs has not yet been explored. We performed a nationwide UK evaluation of BEV use for PLGG to provide large cohort safety & efficacy (radiological & visual) data. A retrospective UK multi-centre analysis of patients treated with BEV for PLGG 2009-2020. Clinical patient, tumour, treatment and toxicity data were analysed from medical records. Age-adjusted LOGMAR visual acuity and radiological MRI assessments (RANO) were reviewed from initiation of BEV until latest follow-up. Standardized radiological & visual criteria assessed efficacy and clinical–radiological correlation. 88 PLGG patients from 11 PTCs received BEV either 3rd-line with irinotecan (85%) or alongside 1st/2nd line chemotherapy (15%) at median age 6 years (0.65-17). Median duration from diagnosis to BEV was 38 months. PLGGs included:15% Non-OPGs, 85% OPGs. Cohort OS 92% at median follow-up 34 months(3-106). Toxicity was limited and minimal. 8% stopped BEV for CTCAE grade 2+ toxicities, & 3 patients had SAEs (2 intracranial haemorrhages, 1 thrombosis) after stopping BEV without obvious alternative cause. Overall radiological response (SD/PR/CR) was 88%; median duration to best response 3 months. Overall visual response (stable/improved) was 72%; median duration to best response 3-6 months. Superior visual outcomes were seen in NF1-OPGs (p=0.02). Concordance between visual and radiological responses was 36%; 48% using best eye only visual responses. 65% patients with treatment response had tumour progression (all-cause) within 8 months of BEV cessation. Visual responses endured significantly longer than radiological responses (p0.03). BEV is a generally safe and effective treatment for PLGG. Most patients demonstrated on-treatment radiological and visual response. Preservation of response after BEV was limited, though visual responses endured better than radiological responses. BEV may have a unique role as a sight-saving strategy in OPG.