DIPG-72. LONG-TERM SURVIVAL OF A CLASSIC DIFFUSE INTRINSIC PONTINE GLIOMA TREATED WITH NIMOTUZUMAB

BACKGROUND: Long-term survival in diffuse intrinsic pontine glioma is rare, and typically associated with atypical imaging and/or atypical clinical course. Although most patients harbor hotspot mutations in H3.1/3-K27M, a proportion of patients have alternate mutations, despite a typical clinicoradiological course. Herein we describe a long-term survivor with a classical presentation, treated with nimotuzumab, highlighting the challenges associated with such cases. CASE REPORT: A 5 year old male, diagnose in 2012 with a 10 day history multiple cranial neuropathies and a right hemiparesis. Cranial MRI revealed a poorly delimited diffuse pontine tumor and secondary hydrocephalus. Tumor biopsy was not performed due to the classic clinical presentation, and he received 54Gy/30 of radiation plus concomitant weekly nimotuzumab 150mg/m2. Initial tumor dimensions were 43x31x28mm. Nimotuzumab 150mg/m2 was continued every 2 weeks. Image assessment at week 12 of treatment revealed 16.9% volume increase, 4 weeks after radiotherapy completion. Nevertheless, subsequent neuroimaging at 24(th), 36(th), 60(th), 96(th) and 108(th) weeks of nimotuzumab therapy showed a sustained and progressive tumor cytoreduction of 47.5%, 59%, 62.2%, 63.8% and 67%, respectively, when compared with post-radiotherapy dimensions. Currently, the patient is 13y old, good school performance, no neurologic disabilities. The last MRI at 394 weeks of nimotuzumab revealed dimensions of 21x19x14mm which corresponds to 70% of reduction compared with initial volume. CONCLUSIONS: Our case of progressive cytoreduction over two years of a classic DIPG, diagnosed in the era prior to the discovery of the K27M mutation, highlights the challenges associated with long-term survival of this devastating entity.