RARE-10. INITIAL EXPERIENCE IN EPENDYMOMA WITH INVESTIGATIONAL CANCER-TARGETING BXQ-350 SapC-DOPS NANOVESICLES: A RARE TUMOR CASE STUDY

• Published in: Neuro-oncology (Charlottesville, Va.) Va.), 2018-11, Vol.20 (suppl_6), p.vi238-vi238
• Main Authors: Puduvalli, Vinay, Villano, John, Wise-Draper, Trisha, Morris, John, Johnson, Angela, SantaCruz, Karen, Kerwin, Audra, Cline-Parhamovich, Karen, Dupis, Edouard, Mabray, Marc, Rixe, Olivier
• Format: Article
• Language: English
• Subjects: Abstracts
• ISSN: 1522-8517; 1523-5866
• DOI: 10.1093/neuonc/noy148.987

Abstract BACKGROUND Ependymomas are rare primary nervous system tumors accounting for about 3% of adult brain tumors in the United States. The current standard of care includes surgical resection and radiation therapy, with more than half experiencing relapse and poor outcomes. Saposin C and dioleylphosphatidylserine (SapC-DOPS) nanovesicles are a novel investigational treatment agent that can cross the blood-brain barrier and selectively target externalized phosphatidylserine that is expressed on tumor cell surfaces. METHODS We examined a rare complex ependymoma case enrolled in the ongoing Phase 1b study of SapC-DOPS cancer-targeting agent BXQ-350 (NCT02859857). The patient received cycle 1 (BXQ-350 2.4 mg/kg IV infusion at Day 1–5, 8, 10, 12, 15, 22) and 3 additional cycles (1x28 days), and was followed until death for safety, response, RANO, and ECOG. RESULTS A 67-year old white male with recurrent Grade III anaplastic ependymoma diagnosed 3 years before enrollment and with a history of surgical intervention exhibited measurable extra-axial (6.4x3.2 cm) and inferolateral intracranial components on MRI, accompanied by palpable skull mass. At baseline, the lesion was 6.4 x 3.2 cm with stable disease per RANO and ECOG of 1. After 2 cycles, minor decrease in size of intracranial enhancing components was reported (overall stable disease per RANO). The patient received 4 total cycles of BQX-350 without related adverse events or toxicities, and cycle 5 was withheld due to volume progression on MRI. He died 6 months post-enrollment. Post-mortem histology and gross anatomy showed extensive tumor necrosis with chondroid differentiation and gross signs of metastatic disease in the lungs, thoracic, and lumbar spine on microscopy. CONCLUSIONS: While further study of cancer-targeting SapC-DOPS nanovesicle efficacy in adult patients with ependymoma is needed, good tolerability in rare aggressive tumors was observed. The role of extensive necrosis and possibly treatment-related intracranial mass reduction supports additional investigations in this indication.