ID #1094 Local Experience with the MEMMAT Regimen for Relapsed Medulloblastoma and ATRT in Hong Kong: Clinical Outcomes and Safety in Shunt-Dependent Patients
Dennis T L Ku, Evelyn R Lu, Christy Y K Mak, Eric C H Fu, Jeffrey P W Yau, Anselm C W Lee, Matthew M K ShingAbstract
Background
Relapsed medulloblastoma (MB) and atypical teratoid rhabdoid tumour (ATRT) present significant therapeutic challenges. The Medulloblastoma European Multitarget Metronomic Anti-Angiogenic Trial (MEMMAT) regimen offers a multi-agent anti-angiogenic approach for these high-risk patients. We aimed to evaluate the local experience in Hong Kong, focusing on the safety of intraventricular (IVe) chemotherapy in patients with ventriculoperitoneal (VP) shunts.
Methods
We retrospectively analyzed 5 paediatric patients (4 MB, 1 ATRT) treated with the MEMMAT regimen. Data on treatment duration, survival and toxicities were extracted from clinical records. For patients with programmable VP shunts (n = 4), a specific safety protocol was implemented: the shunt valve was adjusted to the highest resistance setting for 2 hours post-IVe chemotherapy administration to ensure adequate drug dwell time.
Results
All patients demonstrated clinical and radiological improvement upon starting MEMMAT. For MB patients, MEMMAT was administered for 12 to 25 months with overall survival (OS) following initiation ranging from 13.2 to 55 months. All MB patients underwent re-irradiation as part of the salvage treatment. Toxicity was manageable and included bevacizumab-related proteinuria and hypertension, thalidomide-related drowsiness, and one rare case of suspected celecoxib-related gastric outlet obstruction. One patient developed treatment-related AML 18 months after treatment. The shunt adjustment protocol was well tolerated in all 4 patients without adverse effects or symptoms of raised intracranial pressure.
Conclusion
MEMMAT is a robust regimen for treating children with relapsed MB and ATRT, including those with VP shunts. The 2-hour “highest value” valve adjustment is a safe and effective strategy for IVe drug delivery. Comprehensive training and precise validation of shunt settings are essential to ensure procedural safety.