Eric Burton

Supplemental Fig. 3. ERB-B-2 Status of Patients.

Supplemental Fig. 4. Histogram illustrating ERBB2 relative copy number in plasma and CSF cfDNA samples from 12 patients during their T samples from 12 patients during their Tsamples from 12 patients during their T samples from 12 patients during their T-DM1/TMZ combination therapy.

Supplemental Fig 2. Total mutation Burden by MB.

Supplemental Fig. 1. Neurocognitive assessments comparing patients presenting progression versus no progression.

Purpose:Preclinical data showed that prophylactic, low-dose temozolomide (TMZ) significantly prevented breast cancer brain metastasis. We present results of a phase I trial combining T-DM1 with TMZ for the prevention of additional brain metastases after previous occurrence and local treatment in patients with HER2+ breast cancer.Patients and Methods:Eligible patients had HER2+ breast cancer with brain metastases and were within 12 weeks of whole brain radiation therapy (WBRT), stereotactic radiosurgery, and/or surgery. Standard doses of T-DM1 were administered intravenously every 21 days (3.6 mg/kg) and TMZ was given orally daily in a 3+3 phase I dose escalation design at 30, 40, or 50 mg/m2, continuously. DLT period was one 21-day cycle. Primary endpoint was safety and recommended phase II dose. Symptom questionnaires, brain MRI, and systemic CT scans were performed every 6 weeks. Cell-free DNA sequencing was performed on patients’ plasma and CSF.Results:Twelve women enrolled, nine (75%) with prior SRS therapy and three (25%) with prior WBRT. Grade 3 or 4 AEs included thrombocytopenia (1/12), neutropenia (1/12), lymphopenia (6/12), and decreased CD4 (6/12), requiring pentamidine for Pneumocystis jirovecii pneumonia prophylaxis. No DLT was observed. Four patients on the highest TMZ dose underwent dose reductions. At trial entry, 6 of 12 patients had tumor mutations in CSF, indicating ongoing metastatic colonization despite a clear MRI. Median follow-up on study was 9.6 m (2.8–33.9); only 2 patients developed new parenchymal brain metastases. Tumor mutations varied with patient outcome.Conclusions:Metronomic TMZ in combination with standard dose T-DM1 shows low-grade toxicity and potential activity in secondary prevention of HER2+ brain metastases.

Background: LB100 is a protein phosphatase 2A (PP2A) inhibitor. Glioma models show inhibition of PP2A by LB100 causes cell death. Whether LB100 crosses the human blood brain barrier (BBB) is unknown. We sought to determine the pharmacokinetic (PK) properties of LB100 in human subject gliomas. Methods: A two-stage, phase 0 trial was done. Eligibility required a recurrent adult diffuse type of glioma deemed surgically resectable. In the first stage, 5 patients were pre-surgically dosed with LB100. Resected tumor then underwent PK analysis by LC-MS/MS. If one of five tumors demonstrated a PK response three additional subjects would be enrolled. Pharmacokinetic effect would be declared significant if at least 2 of 8 patients demonstrated a PK response and pharmacodynamic studies would then be performed. Results: Five patients were evaluable. Glioblastoma, (n=2), Astrocytoma IDH-mutant grade 3-4 (n=2), and Oligodendroglioma IDH-mutant, grade 2 (n=1). Mean C _max was 146 ng/mL (range: 95-179 ng/mL). Mean plasma half-life (T _1/2 ) was 1.2 hours (range: 1.09-1.46 hours). Mean plasma drug exposure (AUC _INF ) was 414 hr*ng/mL (range: 325 to 468 ng*hr/mL. Average concentration of LB100 in tumor was 0.19 nM (range: 0 to 0.67 nM). Average plasma concentration of LB100 was 77.26 nM (range: 30.81 to 132.26 nM). The percent of drug penetration into the brain was 0.31% (range: 0% to 1.04%). The IC ₅₀ of PP2A is 0.2-0.4 uM; showing drug penetration was inadequate. Conclusion: In this first PK analysis of LB100 in human gliomas there was poor penetration of LB100 into glial tumors. Statement of Translational Relevance: This phase 0 study represents the first pharmacokinetic (PK) analysis of LB100 in human brain cancers. It demonstrates there is poor penetration of LB100 crossing the blood brain barrier (BBB) into central nervous system (CNS) tumors. The ratio of the LB100 concentration in tumor to plasma tissue was much less than one percent, which resulted in a median LB100 tumor tissue concentration of 0.19 nM or 1000-fold less than a previously established minimum IC50 of 0.2uM, targeting the enzyme protein phosphatase 2A. This study highlights the importance of phase 0 studies as a component of new drug development for patients with CNS tumors. The poor brain tumor penetration demonstrated in this investigation will inform decision making regarding future LB100 clinical trials. Unless efforts are successful to reengineer LB100 to increase BBB permeability, upcoming trials will focus on non-CNS tumors.

Purpose: Multidisciplinary tumor boards (MTBs) integrate clinical, molecular, and radiological information and facilitate coordination of neuro-oncology care. During the COVID-19 pandemic, our MTB transitioned to a virtual and multi-institutional format. We hypothesized that this expansion would allow expert review of challenging neuro-oncology cases and contribute to the care of patients with limited access to specialized centers. Methods: We retrospectively reviewed records from virtual MTBs held between 04/2020–03/2021. Data collected included measures of potential clinical impact, including referrals to observational or therapeutic studies, referrals for specialized neuropathology analysis, and whether molecular findings led to a change in diagnosis and/or guided management suggestions. Results: During 25 meetings, 32 presenters discussed 44 cases. Approximately half (n = 20; 48%) involved a rare central nervous system (CNS) tumor. In 21% (n = 9) the diagnosis was changed or refined based on molecular profiling obtained at the NIH and in 36% (n = 15) molecular findings guided management. Clinical trial suggestions were offered to 31% (n = 13), enrollment in the observational NCI Natural History Study to 21% (n = 9), neuropathology review and molecular testing at the NIH to 17% (n = 7), and all received management suggestions. Conclusion: Virtual multi-institutional MTBs enable remote expert review of CNS tumors. We propose them as a strategy to facilitate expert opinions from specialized centers, especially for rare CNS tumors, helping mitigate geographic barriers to patient care and serving as a pre-screening tool for studies. Advanced molecular testing is key to obtaining a precise diagnosis, discovering potentially actionable targets, and guiding management.

Supplemental Fig. 3. ERB-B-2 Status of Patients.