AT-22ALISERTIB MONOTHERAPY IN THE TREATMENT OF RELAPSED ATYPICAL TERATOID RHABDOID TUMOR (ATRT)

AT-22. ALISERTIB MONOTHERAPY IN THE TREATMENT OF RELAPSED ATYPICAL TERATOID RHABDOID TUMOR (ATRT) Magimairajan Issai Vanan1, Patrick McDonald2, Colin Kazina3, Junliang Liu1, Sherry Krawitz4, Martin Bunge5, Annie Ong1, and Brent Orr6; CancerCare Manitoba/Winnipeg Children’s Hospital, Winnipeg, MB, Canada; Pediatric Neuro-surgery/BC Children’s Hospital, Vancouver, BC, Canada; Pediatric Neuro-Surgery/University of Manitoba, Winnipeg, MB, Canada; Neuropathology/University of Manitoba, Winnipeg, MB, Canada; Radiology/University of Manitoba, Winnipeg, MB, Canada; Pathology/ St Jude Children’s Research Hospital, Memphis, TN, USA Atypical teratoid rhabdoid tumors (ATRTs) account for up to 20% of brain tumors in children less than 3yrs of age. The overall prognosis of ATRTs is extremely poor with median survival in the range of 10-18mths from the time of diagnosis. Aurora A Kinase (AURKA) encodes a protein that regulates the formationandstabilityof themitotic spindleand ishighlyactive inATRTthrough loss of the INI1 tumor suppressor gene. Alisertib (MLN8237) is a selective small molecule inhibitor of AURKA. We report a case of recurrent ATRT treated with alisertib monotherapy producing sustained and durable disease remission. Our patient underwent gross total resection (GTR) of the Posterior fossa tumor at diagnosis and was initially treated as per ACNS0333 protocol. She remained in remission for 15 months after completion of chemotherapy when she relapsed in the right frontal lobe. She underwent sub-total resection (STR) followed by focal IMRT (54Gy/30 fractions) followed by chemotherapy (DFCI-IRS-III, modified protocol) with Doxorubicin / Etoposide alternating with Actinomycin-D and triple intrathecal chemotherapy. After 7 months of treatment, she relapsed again in the right frontal region, presenting with focal seizures. She received 10 cycles of alisertib (60mg/m2 by mouth once daily for 7 days of a 21 day treatment cycle) monotherapyand is clinically stablewith her imaging showingsustained regression of disease. Somnolescence and neutropenia were the most common side effects seen in our patient. Neuro-Oncology 18:iii1–iii6, 2016. doi:10.1093/neuonc/now065.21 #The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.