Impact of Bevacizumab on Visual Function, Tumor Size, and Toxicity in Pediatric Progressive Optic Pathway Glioma: A Retrospective Nationwide Multicentre Study

SIMPLE SUMMARY: Around 30% of children with optic pathway glioma (OPG) require next order systemic anticancer therapy (SAT) in case of progression. Bevacizumab (BVZ) is considered an effective subsequent SAT for pediatric low grade glioma. This retrospective nationwide multicentre study evaluated the effect of treatment with BVZ of 33 children with OPG. A new finding is that visual acuity stabilised (74.4%) or improved (20.5%) after treatment in 39 analysed eyes, visual field stabilised in 15.4% and improved in 73.1% of 25 eyes. Progression free survival from start of treatment decreased from 70.9% at 18 months to 38.0% at 36 months. Reversible severe toxicity was observed in five of 33 patients (15.2%). Our results suggest that the majority of patients with OPG treated with BVZ temporarily stabilize, however most show progression at a later time point. Visual functions, especially visual field, improve in a high percentage of patients. BVZ treatment is suggested to be a useful successive SAT. ABSTRACT: Backgrounds: Bevacizumab (BVZ) is used as a subsequent line of treatment for pediatric optic pathway glioma (OPG) in the case of progression. Data on the treatment effect concerning tumor progression and visual function are scarce and nationwide studies are lacking. Methods: We performed a retrospective, nationwide, multicentre cohort study including all pediatric patients with OPG treated with BVZ in the Netherlands (2009–2021). Progression-free survival, change in visual acuity and visual field, MRI-based radiologic response, and toxicity were evaluated. Results: In total, 33 pediatric patients with OPG were treated with BVZ (median 12 months). Visual acuity improved in 20.5%, remained stable in 74.4%, and decreased in 5.1% of 39 of all analysed eyes. The monocular visual field improved in 73.1%, remained stable in 15.4%, and decreased in 7.7% of 25 analysed eyes. Radiologic response at the end of therapy showed a partial response in 7 patients (21.9%), minor response in 7 (21.9%), stable disease in 15 (46.9%), and progressive disease in 3 (9.3%). Progression-free survival at 18 and 36 months after the start of BVZ reduced from 70.9% to 38.0%. Toxicity (≥grade 3 CTCAE) during treatment was observed in five patients (15.2%). Conclusion: Treatment of BVZ in pediatric patients with OPG revealed stabilisation in the majority of patients, but was followed by progression at a later time point in more than 60% of patients. This profile seems relatively acceptable given the benefits of visual field improvement in more than 70% of analysed eyes and visual acuity improvement in more than 20% of eyes at the cessation of BVZ.