Cumulative Antibiotic Use Significantly Decreases Efficacy of Checkpoint Inhibitors in Patients with Advanced Cancer.

BACKGROUND: With the advent of immunotherapy, substantial progress has been made in improving outcomes for patients with advanced cancer. However, not all patients benefit equally from treatment, and confounding immune-related issues may have an impact. Several studies suggest that antibiotic use (which alters the gut microbiome) may result in poorer outcomes for patients treated with immune checkpoint inhibitors (ICI). MATERIALS AND METHODS: This is a large, single-site retrospective review of n = 291 patients with advanced cancer treated with ICI (n = 179 melanoma, n = 64 non-small cell lung cancer, and n = 48 renal cell carcinoma). Antibiotic use (both single and multiple courses/prolonged use) during the periods 2 weeks before and 6 weeks after ICI treatment was investigated. RESULTS: Within this cohort, 92 patients (32%) received antibiotics. Patients who did not require antibiotics had the longest median progression-free survival (PFS), of 6.3 months, and longest median overall survival (OS), of 21.7 months. With other clinically relevant factors controlled, patients who received a single course of antibiotics had a shorter median OS (median OS, 17.7 months; p = .294), and patients who received multiple courses or prolonged antibiotic treatment had the worst outcomes overall (median OS, 6.3 months; p = .009). Progression-free survival times were similarly affected. CONCLUSION: This large, multivariate analysis demonstrated that antibiotic use is an independent negative predictor of PFS and OS in patients with advanced cancer treated with ICIs. This study highlighted worse treatment outcomes from patients with cumulative (multiple or prolonged courses) antibiotic use, which warrants further investigation and may subsequently inform clinical practice guidelines advocating careful use of antibiotics. IMPLICATIONS FOR PRACTICE: Antibiotic use is negatively associated with treatment outcomes of immune checkpoint inhibitors (ICI) in advanced cancer. Cumulative antibiotic use is associated with a marked negative survival outcome. Judicious antibiotic prescribing is warranted in patients receiving treatment with ICI for treatment of advanced malignancy.

Utility of ctDNA to support patient selection for early phase clinical trials: the TARGET study.

Next-generation sequencing (NGS) of circulating tumor DNA (ctDNA) supports blood-based genomic profiling but is not yet routinely implemented in the setting of a phase I trials clinic. TARGET is a molecular profiling program with the primary aim to match patients with a broad range of advanced cancers to early phase clinical trials on the basis of analysis of both somatic mutations and copy number alterations (CNA) across a 641 cancer-associated-gene panel in a single ctDNA assay. For the first 100 TARGET patients, ctDNA data showed good concordance with matched tumor and results were turned round within a clinically acceptable timeframe for Molecular Tumor Board (MTB) review. When a 2.5% variant allele frequency (VAF) threshold was applied, actionable mutations were identified in 41 of 100 patients, and 11 of these patients received a matched therapy. These data support the application of ctDNA in this early phase trial setting where broad genomic profiling of contemporaneous tumor material enhances patient stratification to novel therapies and provides a practical template for bringing routinely applied blood-based analyses to the clinic.

An unusual case of leptomeningeal carcinomatosis in a patient with primary adenocarcinoma of the lung.

A 72-year-old man was brought to the emergency department with acute onset confusion and haemoptysis. Chest X-ray showed a possible lung mass, while CT head showed a fluid-filled, space-occupying lesion (SOL) in the right frontal lobe of the brain. MRI head indicated that this SOL had spilt its contents into the subarachnoid and intraventricular spaces. Due to a fluctuating Glasgow Coma Scale (GCS), the patient underwent emergency debulking. Macroscopically, a frail-walled cystic tumour filled with straw-coloured fluid was noted; histology confirmed metastasis from a primary lung adenocarcinoma. Whole brain radiotherapy was given, with a view to commence systemic therapy. The patient, however, deteriorated and unfortunately passed away a few weeks after completing radiotherapy. This patient presented with leptomeningeal metastasis as the first presentation of a lung adenocarcinoma, and had a highly unusual mechanism by which leptomeningeal spread had occurred, with metastatic brain tumour spilling its contents into the meningeal spaces.