Effectiveness, safety, and drug sustainability of biologics in elderly patients with inflammatory bowel disease: A retrospective study

BACKGROUND

Biologic therapy resulted in a significant positive impact on the management of inflammatory bowel disease (IBD) however data on the efficacy and side effects of these therapies in the elderly is scant.

AIM

To evaluate retrospectively the drug sustainability, effectiveness, and safety of the biologic therapies in the elderly IBD population.

METHODS

Consecutive elderly (≥ 60 years old) IBD patients, treated with biologics [infliximab (IFX), adalimumab (ADAL), vedolizumab (VDZ), ustekinumab (UST)] followed at the McGill University Inflammatory Bowel Diseases Center were included between January 2000 and 2020. Efficacy was measured by clinical scores at 3, 6-9 and 12-18 mo after initiation of the biologic therapy. Patients completing induction therapy were included. Adverse events (AEs) or serious AE were collected during and within three months of stopping of the biologic therapy.

RESULTS

We identified a total of 147 elderly patients with IBD treated with biologicals during the study period, including 109 with Crohn’s disease and 38 with ulcerative colitis. Patients received the following biologicals: IFX (28.5%), ADAL (38.7%), VDZ (15.6%), UST (17%). The mean duration of biologic treatment was 157.5 (SD = 148) wk. Parallel steroid therapy was given in 34% at baseline, 19% at 3 mo, 16.3% at 6-9 mo and 6.5% at 12-18 mo. The remission rates at 3, 6-9 and 12-18 mo were not significantly different among biological therapies. Kaplan-Meyer analysis did not show statistical difference for drug sustainability (P = 0.195), time to adverse event (P = 0.158) or infection rates (P = 0.973) between the four biologics studied. The most common AEs that led to drug discontinuation were loss of response, infusion/injection reaction and infection.

CONCLUSION

Current biologics were not different regarding drug sustainability, effectiveness, and safety in the elderly IBD population. Therefore, we are not able to suggest a preferred sequencing order among biologicals.

The Microbiome as a Therapy in Pouchitis and Ulcerative Colitis

The gut microbiome has been implicated in a range of diseases and there is a rapidly growing understanding of this ecosystem's importance in inflammatory bowel disease. We are yet to identify a single microbe that causes either ulcerative colitis (UC) or pouchitis, however, reduced microbiome diversity is increasingly recognised in active UC. Manipulating the gut microbiome through dietary interventions, prebiotic and probiotic compounds and faecal microbiota transplantation may expand the therapeutic landscape in UC. Specific diets, such as the Mediterranean diet or diet rich in omega-3 fatty acids, may reduce intestinal inflammation or potentially reduce the risk of incident UC. This review summarises our knowledge of gut microbiome therapies in UC and pouchitis.

Ulcerative colitis: an update

Ulcerative colitis is a relapsing and remitting disease that is increasing in incidence and prevalence. Management aims to achieve rapid resolution of symptoms, mucosal healing and improvement in a patient's quality of life. 5-aminosalicylate acid medications remain the first-line treatment for mild to moderate disease. In the event of suboptimal response to these medications, escalation to immunosuppressive medications and biologics may be necessary. Importantly, despite best medical therapy, surgery may be required in a proportion of patients. The future will likely see an array of new therapeutic options for those with ulcerative colitis with the potential for a more personalised treatment approach.

Are we addressing the top 10 research priorities in IBD?

BACKGROUND

Since publication of the top 10 research priorities in inflammatory bowel disease (IBD) based on the James Lind Alliance Priority Setting Partnership, the question remains whether this has influenced the IBD-research landscape. This study aimed to create an overview of the current distribution of research interests of trials in the UK.

METHODS

The ClinicalTrials.gov database and European Union Clinical Trials Register were screened for clinical trials set up from 9 August 2016 to 16 November 2019 in the UK involving adult patients with IBD.

RESULTS

Of 20 non-industry-sponsored studies, a quarter investigated treatment strategies considering efficacy, safety and cost-effectiveness (priority 1). Four evaluated the role of diet (priorities 3 and 7). Development/assessment of biomarkers for patient stratification (priority 2) and fatigue (priority 8) were subject of three studies. IBD-related pain and control of diarrhoea/incontinence were each subject of 2 studies (priorities 4 and 6). The effect of gut microbiota (priority 10) and optimal strategy for perianal Crohn's disease (priority 5) was the focus of 2 studies each. One study evaluated surgery for terminal ileal Crohn's disease (priority 9). Of 63 industry-sponsored studies, 59 focused on priority 1.

CONCLUSIONS

This study presents an impression of the breadth of the IBD-research landscape in the UK, in light of the top 10 research priorities published in 2016. Optimal treatment strategy has been the most studied research priority by academic and industry-sponsored trials. Fewer studies focused on patient-reported outcomes. It remains debatable to what extent the current research landscape adequately represents all stakeholders' viewpoints on needs for expanded knowledge in IBD, particularly the patients' perspective.

Elderly patients with inflammatory bowel disease: Updated review of the therapeutic landscape

High-quality data remains scarce in terms of optimal management strategies in the elderly inflammatory bowel disease (IBD) population. Indeed, available trials have been mostly retrospective, of small sample size, likely owing to under-representation of such a population in the major randomized controlled trials. However, in the last five years, there has been a steady increase in the number of published trials, helping clarify the estimated benefits and toxicity of the existing IBD armamentarium. In the Everhov trial, prescription strategies were recorded over an average follow-up of 4.2 years. A minority of elderly IBD patients (1%-3%) were treated with biologics within the five years following diagnosis, whilst almost a quarter of these patients were receiving corticosteroid therapy at year five of follow-up, despite its multiple toxicities. The low use of biologic agents in real-life settings likely stems from limited data suggesting lower efficacy and higher toxicity. This minireview will aim to highlight current outcome measurements as it portends the elderly IBD patient, as well as summarize the available therapeutic strategies in view of a growing body of evidence.

Kinesin-mediated axonal transport of a membrane compartment containing beta-secretase and presenilin-1 requires APP

Proteolytic processing of amyloid precursor protein (APP) generates amyloid-beta peptide and has been implicated in the pathogenesis of Alzheimer's disease. However, the normal function of APP, whether this function is related to the proteolytic processing of APP, and where this processing takes place in neurons in vivo remain unknown. We have previously shown that the axonal transport of APP in neurons is mediated by the direct binding of APP to the kinesin light chain subunit of kinesin-I, a microtubule motor protein. Here we identify an axonal membrane compartment that contains APP, beta-secretase and presenilin-1. The fast anterograde axonal transport of this compartment is mediated by APP and kinesin-I. Proteolytic processing of APP can occur in the compartment in vitro and in vivo in axons. This proteolysis generates amyloid-beta and a carboxy-terminal fragment of APP, and liberates kinesin-I from the membrane. These results suggest that APP functions as a kinesin-I membrane receptor, mediating the axonal transport of beta-secretase and presenilin-1, and that processing of APP to amyloid-beta by secretases can occur in an axonal membrane compartment transported by kinesin-I.

Ligand induction of retinoic acid receptors alters an acute infection by murine cytomegalovirus

Here we report that administration of retinoids can alter the outcome of an acute murine cytomegalovirus (MCMV) infection. We show that a crucial viral control element, the major immediate-early enhancer, can be activated by retinoic acid (RA) via multiple RA-responsive elements (DR2) that bind retinoid X receptor-retinoic acid receptor (RAR) heterodimers with apparent dissociation constants ranging from 15 to 33 nM. Viral growth is dramatically increased upon RA treatment of infected tissue culture cells. Using synthetic retinoid receptor-specific agonists and antagonists, we provide evidence that RAR activation in cells is required for mediating the response of MCMV to RA. Oral administration of RA to infected immunocompetent mice selectively exacerbates an infection by MCMV, while cotreatment with an RAR antagonist protects against the adverse effects of RA on MCMV infection. In conclusion, these chemical genetic experiments provide evidence that an RAR-mediated pathway can modulate in vitro and in vivo infections by MCMV.

Recognition properties of a sequence-specific DNA binding antibody

A sequence-specific DNA-binding antibody was previously generated by incorporating a 17 amino acid alpha-helix from the DNA-binding domain of the transcription factor TFEB into the HCDR3 site of a recombinant human Fab fragment. The recombinant DNA-binding antibody, called Fab-E box, binds the TFEB recognition sequence CACGTG (an E box site) with a 5-10-fold lower affinity than TFEB. Here, we have determined the precise kinetics of interaction of Fab-E box with DNA and show that the lower affinity of Fab-E box relative to TFEB for E box DNA is due to a higher dissociation rate. DNase I protection assays show Fab-E box physically interacts with one half-site of the E box. Additional DNA target sites of Fab-E box were identified by DNase I protection assays. A compilation of these binding sites indicates that the recognition elements for Fab-E box binding include a half-site of the E box, CAW, with an 8 bp consensus sequence identified as YNYYCAWW. Thus, the DNA determinants for Fab-E box recognition extend beyond one-half site of the E box sequence, with preferences for pyrimidines and A+T-rich sequences in the 5' and 3' outer regions of the binding site, respectively. Apparent dissociation constants of Fab-E box for a subset of these target DNA sequences are 5-10-fold greater than the DNA-binding affinity of the antibody with the E box site. Therefore, these results identify important DNA specificity determinants for high-affinity binding by Fab-E box.

Contributions of the TATA box sequence to rate-limiting steps in transcription initiation by RNA polymerase II

We have examined the role of the TATA box in determining transcription initiation frequency in vitro by studying a collection of promoters containing different TATA sequences in the context of the adenovirus major late promoter. In addition to measuring transcription rates, we have determined how the sequence changes affected the association and dissociation kinetics and the affinity of TBP binding. We observed that transcription from promoters containing the highest affinity TATA boxes is limited by the rate with which TBP associates with the promoter. In contrast, transcription from promoters containing lower affinity TATA boxes appears to be limited both by how much TBP is bound and by the relatively low occupancy of the conformation that can undergo subsequent steps in preinitiation complex assembly. The implications of these results in understanding the mechanism of transcription enhancement by transcriptional activators is discussed.

Generation of a transcription map at the HSD17B locus centromeric to BRCA1 at 17q21

A detailed transcription map of the 320-kb region containing the HSD17B locus on chromosome 17 was generated. Thirty unique cDNA fragments, retrieved following the hybridization of immobilized YACs to primary pools of cDNAs prepared from RNA of mammary gland, ovary, placenta, and the Caco-2 cell line, were aligned into 10 transcription units by physical mapping and hybridization to RNAs of a series of tissues. The cDNAs were then further characterized by sequencing and used to screen mammary gland cDNA libraries. Fragments corresponding to the broadly expressed gamma-tubulin and Ki antigen genes were identified. A full-length cDNA clone encoding a 117-amino-acid protein homologous to the rat ribosomal protein L34 was isolated. Portions of genes with restricted patterns of expression were also obtained, including the previously characterized HSD17B1. One new gene, for which a full-length cDNA was isolated, was found to have an interesting tissue-specific pattern of expression with abundant mRNA in both the colon and the testis and in the mammary carcinoma cell line BT-474. This contrasted with the barely detectable level observed in several tissues including normal mammary gland. Of the five additional transcription units identified, one showed no similarity, two showed identity to human expressed sequences, and two displayed similarity to genes of animal species by amino acid alignment. These latter cDNA clones include potential homologues of a rat nuclear tyrosine phosphatase and of a factor of Drosophila that is known to be involved in the negative regulation of transcription of segment identity genes.

Kinetic analysis of yeast TFIID-TATA box complex formation suggests a multi-step pathway

The eukaryotic transcription factor TFIID recognizes and binds a promoter sequence element called the TATA box. We have analyzed the interaction of yeast TFIID with the consensus TATA box sequence of the adenovirus major late promoter. To facilitate this detailed characterization, we developed a method for obtaining quantitative information from a gel retardation (bandshift) assay, allowing measurement of the rate and extent of TFIID-TATA box complex formation. Using this assay and DNase I protection assays, we determined that the association rate constant for TFIID binding to the major late promoter was too low to be consistent with a simple diffusion-limited association, suggesting that the binding proceeds by a multi-step pathway. Furthermore, we found that the slow rate of TFIID binding reported by other research groups was not the consequence of a rate-limiting conformational change, as has been previously suggested. Instead, we observed that the formation of a stable TFIID-TATA box complex was relatively rapid (complete in less than 1 min) at saturating concentrations of TFIID. We have proposed a two-step pathway consistent with the observed kinetics and have considered the possible contributions of each step to the overall rate of TFIID binding. This study lays the groundwork for a systematic characterization of the interaction of TFIID with additional TATA box sequences, including an experimental test of the possibility that different steps in the binding reaction are rate-limiting for different promoters.