A phase I dose-escalation study of pulsatile afatinib in patients with recurrent or progressive brain cancer

Background

Afatinib (BIBW2992; Gilotrif®) is a selective and irreversible inhibitor of the epidermal growth factor receptor (ErbB; EGFR) family. It inhibits EGFR, HER2, and HER4 phosphorylation, resulting in tumor growth inhibition and regression. This phase I dose-escalation trial of pulsatile afatinib examined the safety, drug penetration into the central nervous system, preliminary antitumor activity, and recommended phase II dose in patients with progressive or recurrent brain cancers.

Methods

Afatinib was taken orally once every 4 days or once every 7 days depending on dose cohort, until disease progression or unacceptable toxicity.

Results

A total of 24 patients received the investigational agent and were evaluable for safety analyses, and 21 patients were evaluable for efficacy. Dosing was administered at 80 mg every 4 days, 120 mg every 4 days, 180 mg every 4 days, or 280 mg every 7 days. A recommended phase II dose of pulsatile afatinib was established at 280 mg every 7 days as there were no dose-limiting toxicities in any of the dosing cohorts and all toxicities were deemed manageable. The most common drug-related toxicities were diarrhea, rash, nausea, vomiting, fatigue, stomatitis, pruritus, and limb edema. Out of the 21 patients evaluable for efficacy, 2 patients (9.5%) exhibited partial response based on Response Assessment in Neuro-Oncology criteria and disease stabilization was seen in 3 patients (14.3%).

Conclusions

Afatinib taken orally was safe and well-tolerated up to 280 mg every 7 days in brain cancer patients.

Characterization of molecular pathways for targeting therapy in glioblastoma

Glioblastoma remains the most common malignant brain neoplasm in adults. The available therapies for treatment have only modestly extended survival. Traditional chemotherapy agents have shown only slight effectiveness in controlling this disease. The use of molecular profiling has allowed personalized medicine options to be explored for the care of these individuals. Targeted therapies have shown significant benefit in numerous other cancer types with survival being extended significantly. In glioblastoma, several promising markers have been identified including vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR), and programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1). These targets have been shown to play a critical role in glioblastoma formation and proliferation. The pathways of these receptors have been elucidated in detail. This level of understanding has led to the a more robust understanding of possible mechanism of pathway modification. The targeting of these specific markers has led to the development of several selective therapies with additional therapies being evaluated. The clinical trials validating these markers have been promising but have yet to show a clear benefit in brain tumors. This identification of alternative methods to address these markers or identify additional targets may be the key to the fight against this disease. The molecular targeting of glioblastoma pathways may have significant impact on disease control and patient survival.

The next generation of cerebrospinal fluid (CSF)-based molecular diagnostics: Improving sensitivity and actionability in breast and lung cancer patients with CNS involvement

e14502

Background: Liquid biopsy has emerged as a minimally invasive and cost-effective strategy to assess cancer biomarkers without the risk of complications associated with surgical biopsies. Once a tumor has metastasized to the brain, circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) can be found in the cerebrospinal fluid (CSF). We analyzed CSF samples from patients(pts) with primary lung or breast cancer with either brain (BM) or leptomeningeal metastases (LM). Here we report the analytical and clinical validation of Target Selector CSF assays. Validation testing included pre-analytical and analytical steps. Methods: CSF was collected prospectively from pts with a prior solid tumor diagnosis and suspected BM or LM. CTCs were captured utilizing a primary ten antibody cocktail followed by biotinylated secondary antibodies that bind selectively to CTCs followed by staining with cytokeratin (CK), CD45, streptavidin and DAPI. CTCs were captured in a microfluidic channel,classified as either CK+ or CK-. Cell-free total nucleic acids (cfTNA) was extracted from CSF supernatant and underwent both Target Selector™ single gene and next-generation sequencing (NGS) lung and breast multi-gene testing to assess for molecular alterations. For NGS, data analysis was performed using Torrent Suite with annotation and curation by Ion Reporter and Oncomine Knowledgebase Reporter software. Results: The Target Selector CTC platform assays performed on clinical samples (n = 89) resulted in clinical accuracy = 85.4%, clinical precision (intra-assay, inter-assay, inter-operator, and inter-instrument) = 100% for each measure, clinical sensitivity = 80.0%, clinical specificity = 96.6%, positive predictive value (PPV) = 98%, negative predictive value (NPV) = 70.0%, and analytical specificity = 96.0% (acceptance criteria was 95%) at a limit of detection of 2 CTCs. For molecular analyses, Target Selector™ platform assays resulted in clinical accuracy = 87.4%, clinical sensitivity = 85.2%, clinical specificity = 88.3%, PPV = 76.7%, and NPV = 93.0%. Conclusions: Target Selector is a viable, sensitive, reproducible platform for CTC detection and molecular analysis of CSF samples from patients with breast or lung cancer with CNS metastases especially as the sensitivity of CSF cytology is low and MRI findings can be equivocal. Identifying CTCs and molecular alterations can help characterize both tumor genomic evolution as well as guide treatment following cancer metastasis to the CNS.