CT-P13 is the first subcutaneous infliximab molecule approved for the management of inflammatory bowel disease (IBD). Compared to intravenous therapy, SC infliximab offers a range of practical, micro- and macroeconomic advantages. Data from the rheumatological literature suggest that subcutaneous CT-P13 may lead to superior disease outcomes in comparison to intravenous infliximab. Existing studies in IBD have focussed on pharmacokinetic comparisons and are inadequately powered to evaluate efficacy and safety differences between the two modes of administration. However, emerging clinical trial and real-world data support comparable clinical, biochemical, endoscopic and safety outcomes between subcutaneous and intravenous infliximab in both luminal Crohn’s disease and ulcerative colitis. Across the available data, subcutaneous CT-P13 provides relative pharmacokinetic stability and higher trough drug levels when compared to intravenous administration. The clinical impact of this observation on immunogenicity and treatment persistence is yet to be determined. Trough levels between the two methods of administration should not be compared in isolation as any subcutaneous advantage must be considered in the context of comparable total drug exposure and the theoretical disadvantage of lower peak concentrations compared to intravenous therapy. Furthermore, target drug levels for subcutaneous CT-P13 associated with remission are not known. In this review, we present the available literature surrounding the pharmacokinetics of subcutaneous CT-P13 in the context of therapeutic drug monitoring and highlight the potential significance of these observations on the clinical management of patients with IBD.

Immune checkpoint inhibitors (ICI) are a form of immunotherapy that have revolutionized the treatment of a number of cancers. Specifically, they are antibodies targeted against established and emerging immune checkpoints, such as cytotoxic T-cell antigen 4 (CTLA4), programmed cell death ligand 1 (PD-L1) and programmed cell death 1 protein (PD-1) on CD8-positive T cells, which promote the destruction of tumor cells. While the immune checkpoint inhibitors are very effective in the treatment of a number of cancers, their use is limited by serious and in some cases life-threatening immune-related adverse events. While these involve many organs, one of the most prevalent serious adverse events is immune checkpoint inhibitor colitis, occurring in a significant proportion of patients treated with this therapy. In this review, we aim to broadly describe the immune-related adverse events known to occur within the gastrointestinal system and the potential role played by the intestinal microbiome.

Metastasis is considered one of the hallmarks of cancer and enhanced tumor invasion and metastasis is significantly associated with cancer mortality. Metastasis occurs via a series of integrated processes involving tumor cells and the tumor microenvironment. The innate immune components of the microenvironment have been shown to engage with tumor cells and not only regulate their proliferation and survival, but also modulate the surrounding environment to enable cancer progression. In the era of immune therapies, it is critical to understand how different innate immune cell populations are involved in this process. This review summarizes recent literature describing the roles of innate immune cells during the tumor metastatic cascade.

Prostate-specific membrane antigen (PSMA) positron emission tomography (PET) is widely used in prostate cancer. Recent studies indicate hepatocellular carcinoma (HCC) demonstrates PSMA PET uptake. The diagnostic accuracy of PSMA PET for HCC is not known. We conducted a systematic review and meta-analysis of studies assessing ⁶⁸Ga-PSMA-11 in HCC. Nine studies were included, with 196 patients and a total of 491 HCC lesions. Per-patient analysis yielded a pooled sensitivity of 89.8% (95% CI 78.5–95.5). Specificity was poorly reported, with insufficient data. When per-lesion level analysis was performed on seven studies, the pooled sensitivity was 94.5% (95% CI 82.9–98.4), and specificity was again poorly reported with insufficient data. Among the three studies with adequate data for full per-lesion meta-analysis, 115 lesions in 41 patients demonstrated sensitivity of 97.1% (95% CI 87.8–99.4), while specificity was 42.2% (95% CI 0.3–99.4). Two studies provided sufficient data for meta-analysis on a per-patient level (n = 50 patients), demonstrating a sensitivity of 92.5% (95% CI 64.0–98.9) and specificity of 72.4% (95% CI 1.3–99.8). PSMA PET demonstrates a high sensitivity for HCC and shows promise as an imaging modality for diagnosis and staging of HCC. However, the existing literature does not provide enough data to confidently evaluate its specificity and, therefore, accuracy. Further prospective studies are necessary, with a focus on the accurate reporting of benign lesions and inclusion of patients with an intermediate probability of HCC.

Introduction A substantial proportion of patients with inflammatory bowel disease (IBD) on intravenous infliximab require dose intensification. Accessing additional intravenous infliximab is labour-intensive and expensive, depending on insurance and pharmaceutical reimbursement. Observational data suggest that subcutaneous infliximab may offer a convenient and safe alternative to maintain disease remission in patients requiring dose-intensified infliximab. A prospective, controlled trial is required to confirm that subcutaneous infliximab is as effective as dose-intensified intravenous infliximab, to identify predictors of disease flare and to establish the role of subcutaneous infliximab therapeutic drug monitoring. Methods and analysis The DISCUS-IBD trial is an investigator-initiated, prospective, multicentre, randomised, open-label non-inferiority study comparing the rate of disease flares in participants randomised to continue dose-intensified intravenous infliximab to those switched to subcutaneous infliximab after 48 weeks. Participants are adult patients with IBD in sustained corticosteroid-free remission on any regimen of dose-intensified infliximab up to a maximum of 10 mg/kg 4-weekly intravenously. Participants allocated to intravenous infliximab will continue infliximab at the same dose-intensified regimen they were receiving at study enrolment. Subcutaneous infliximab dosing will be stratified by prior intravenous infliximab dosing. Clinical (Harvey-Bradshaw Index, partial Mayo score), biochemical (C reactive protein, faecal calprotectin), pharmacokinetic (drug-level±antidrug antibodies) and qualitative data are collected 12-weekly until study conclusion at week 48. 13 sites across Australia will participate in recruitment to reach a calculated sample size of 120 participants. Ethics and dissemination Multisite ethics approval was obtained from the Health District Human Research Ethics Committee (HREC) at The Alfred Hospital under a National Mutual Acceptance (NMA) agreement (HREC/90559/Alfred-2022; Local Reference: Project 618/22, version 1.6, 2 March 2023). Findings will be reported at national and international gastroenterology meetings and published in peer-reviewed journals. DISCUS-IBD was prospectively registered with the Australian and New Zealand Clinical Trials Registry (ANZCTR) prior to commencing recruitment. Trial registration number ACTRN12622001458729.

Li-Fraumeni Syndrome (LFS), caused by germline pathogenic variants in TP53, predisposes to a wide range of young-onset malignancies, particularly sarcoma, breast and brain cancer. More recently, an increased risk of gastric adenocarcinoma has been recognised, although uptake of surveillance upper endoscopy is unclear. Our retrospective review of 65 patients with LFS, of whom 53.8% had undergone endoscopy, identified four patients (6.2%) with gastro-esophageal junction (GEJ) adenocarcinomas. Two cases were found on asymptomatic screening and were early stage. No cases had family history of gastrointestinal malignancy. Reviewing genomic data from The Cancer Genome Atlas Program, 76.4% of sporadic esophageal adenocarcinomas harboured somatic TP53 pathogenic variants, compared with 39.9% of non-cardia gastric cancers. This similar pattern observed in germline and sporadic cases warrants further investigation. We propose that upper endoscopy be recommended to all patients with LFS, with a focus on appropriate surveillance of the GEJ.