Achieving Mucosal Healing in Inflammatory Bowel Diseases: Which Drug Concentrations Need to Be Targeted?

Activation of P2Y1R impedes intestinal mucosa repair during colitis

Delayed intestinal mucosal healing is one of the pathogenic bases for the recurrence of inflammatory bowel disease (IBD), but how the IBD inflammatory environment impedes intestinal mucosa repair remains unclear. Adenosine diphosphate (ADP) is an endogenous ligand of P2Y1R that is highly produced at sites of inflammation. We herein identify a novel role of ADP to directly facilitate inflammation-induced epithelial permeability, delay wound healing, and disrupt tight junction integrity, and we found that P2Y1R, a receptor preferentially activated by ADP, was significantly upregulated in the colonic mucosa of ulcerative colitis (UC) patients and in colonic epithelial cells of colitis mice. Inhibition of P2Y1R significantly increased the epithelial permeability, decreased the wound healing capacity, and impaired the tight junction integrity in TNF-α-challenged Caco-2 cells. In parallel, the same effects in promoting intestinal mucosa repair were observed in DSS-induced colitis in P2Y1R-/- mice. Mechanistic investigation revealed that P2Y1R inhibition facilitated epithelial AMP-activated protein kinase (AMPK) phosphorylation and gut microbiota homeostasis reconstruction. Taken together, these findings highlight that P2Y1R activation plays an important role in impeding intestinal mucosa repair during colitis, and that P2Y1R is an attractive target for the therapy of IBD.

Efficacy and Safety of Ivarmacitinib in Patients With Moderate-to-Severe, Active, Ulcerative Colitis: A Phase II Study

BACKGROUND & AIMS

Current therapies for ulcerative colitis (UC) fail to achieve satisfactory disease control. Selective inhibition of Janus kinase (JAK) type 1 may improve clinical outcomes in patients with UC while avoiding the side effects associated with pan-JAK inhibition. The safety and efficacy of the selective JAK1 inhibitor ivarmacitinib (formerly SHR0302) were evaluated in patients with moderate-to-severe, active UC.

METHODS

AMBER2 was a double-blind, placebo-controlled, phase II trial conducted at 63 clinical centers in China, the United States, and Europe. Patients (N = 164) were randomized 1:1:1:1 to receive oral ivarmacitinib 8 mg once daily (QD), 4 mg twice daily (BID), or 4 mg QD, or placebo for 8 weeks, followed by an 8-week extension period. The primary endpoint was clinical response rate at week 8. Hochberg's procedure was used to control the study-wise type 1 error at alpha=0.1.

RESULTS

A total of 146 (89.0%) patients completed 8 weeks of treatment. Week 8 clinical response rates were significantly higher in the 8 mg QD (46.3%; P = .066), 4 mg BID (46.3%; P = .059), and 4 mg QD (43.9%; P = .095) groups vs placebo (26.8%). Week 8 rates of clinical remission were 22.0% (P = .020), 24.4% (P = .013), and 24.4% (P = .011) in the 3 ivarmacitinib treatment groups, respectively, vs 4.9% for placebo. During the initial 8-week period, treatment-emergent adverse events occurred in 43.9% to 48.8% of ivarmacitinib-treated patients and in 39.0% of the placebo group, and were predominantly mild. There were no deaths, or major adverse cardiovascular or thromboembolic events.

CONCLUSION

Ivarmacitinib demonstrated clinical efficacy and was well tolerated in patients with moderate-to-severe, active, UC. Ivarmacitinib represents a promising new treatment for moderate-to-severe UC.

CLINICALTRIALS

gov number, NCT03675477.

Recent advancements in clearance monitoring of monoclonal antibodies in patients with inflammatory bowel diseases

INTRODUCTION

Less than 50% of patients with inflammatory bowel diseases (IBD) receiving monoclonal antibody (mAb) therapy achieve endoscopic remission. Poor outcomes may indicate a need for dose optimization. During therapeutic drug monitoring (TDM), drug concentrations are measured, and when found too low, dosage regimen escalations are performed. To date, benefits of TDM of mAbs in patients with IBD are uncertain.

AREAS COVERED

This review presents an overview of what clearance monitoring is, how it can be performed, and why and when it may be valuable in treating patients with IBD. Virtual patients were used for illustration. A literature search was performed to summarize current evidence for clearance monitoring in IBD and other disease settings.

EXPERT OPINION

During clearance monitoring, mAb clearance is calculated and monitored over time. Higher mAb clearance in patients with IBD has been associated with higher target load (target-mediated drug disposition), protein-losing enteropathy (fecal drug loss), and immunogenicity. Although not prospectively confirmed, clearance monitoring might facilitate identification of (yet) asymptomatic disease flares or presence of (yet) undetectable anti-drug antibodies. Furthermore, clearance monitoring may be used to predict treatment outcomes. Whether dosage regimen adjustments can modify the clearance time course and the treatment outcome is to be determined.

A minimal physiologically based pharmacokinetic model to characterize colon TNF suppression and treatment effects of an anti-TNF monoclonal antibody in a mouse inflammatory bowel disease model

Biotherapeutic drugs against tumor necrosis factor (TNF) are effective treatments for moderate to severe inflammatory bowel disease (IBD). Here, we evaluated CNTO 5048, an antimurine TNF surrogate monoclonal antibody (mAb), in a CD45RB^high adoptive T cell transfer mouse colitis model, which allows examination of the early immunological events associated with gut inflammation and the therapeutic effects. The study was designed to quantitatively understand the effects of IBD on CNTO 5048 disposition, the ability of CNTO 5048 to neutralize pathogenic TNF at the colon under disease conditions, and the impact of dosing regimen on CNTO 5048 treatment effect. CNTO 5048 and TNF concentrations in both mice serum and colon homogenate were also measured. Free TNF concentrations in colon, but not in serum, were shown to correlate well with the colon pharmacodynamic readout, such as the summed histopathology score and neutrophil score. A minimal physiologically based pharmacokinetic (mPBPK) model was developed to characterize CNTO 5048 PK and disposition, as well as colon soluble TNF target engagement (TE). The mPBPK/TE model reasonably captured the observed data and provided a quantitative understanding of an anti-TNF mAb on its colon TNF suppression and therapeutic effect in a physiologically relevant IBD animal model. These results also provided insights into the potential benefits of using induction doses for the treatment of IBD patients.

Noninvasive Targeted Crohn Disease Management by Combining Endoscopic Healing Index and Therapeutic Drug Monitoring

Background and Aims

Therapeutic drug monitoring (TDM) with measurement of serum drug and antidrug antibody concentrations is used to optimize tumor necrosis factor antagonists (anti-TNF). The endoscopic healing index (EHI) is a validated serum-based assay to measure mucosal inflammation in adults with Crohn disease (CD). Our objectives were to evaluate the relationship between EHI and TDM results and to determine the anti-TNF concentration range associated with EHI <20 (consistent with endoscopic remission).

Methods

Adult and pediatric patients with CD (N = 1731) were selected retrospectively from a clinical laboratory cohort. Patients were selected if they had an ICD-10 code for CD and if results for EHI and TDM were available within 30 days of each other. The relationship between EHI and TDM results was examined and the anti-TNF concentration range associated with EHI <20 vs >50 was evaluated.

Results

Median anti-TNF concentration was higher in patients with EHI <20 vs >50 for infliximab (N = 796): 11.1 vs 3.4 µg/mL and for adalimumab (N = 935): 9.2 vs 5.0 µg/mL (P < 0.0001 both drugs). Patients with antibodies to infliximab (12.8%) or adalimumab (14.9%) had lower anti-TNF concentrations (P < 0.001 both drugs) and higher EHI (P < 0.01 both drugs). The concentration range for infliximab: 5-15 µg/mL (5-9 µg/mL in pediatric patients) and for adalimumab: 5-10 µg/mL (8 µg/mL in pediatric patients) best discriminated EHI <20 vs >50.

Conclusions

We report the anti-TNF concentration range associated with EHI <20. Combined testing of EHI and TDM is proposed as a noninvasive approach for treat-to-target management which could improve the ability to monitor disease and optimize anti-TNF therapy.

Assessing adherence to infusion-based biologic therapies in patients with inflammatory bowel disease

BACKGROUND

The intravenous biologics infliximab and vedolizumab are effective long-term therapies for inflammatory bowel disease (IBD). Though highly effective, suboptimal adherence may result in loss of response and adverse sequelae. The extent and outcomes of suboptimal adherence with intravenous biologics, including in IBD, requires further evaluation.

OBJECTIVES

To ascertain adherence to infliximab and vedolizumab infusions, and determine factors associated with poorer adherence within an IBD cohort.

METHODS

A retrospective single-centre cohort study of IBD patients, assessing adherence to infliximab and vedolizumab over 2 years (July 1, 2017 to June 30, 2019) was conducted. Medical and pharmacy dispensing records were used to determine date of infusion. Adherence was assessed using the continuous, multiple interval measure of medication gaps (CMG). Objectively measured disease remission was achieved if one or more of endoscopic remission, faecal calprotectin <100 μg/mL and/or CRP <5 mg/mL occurred within 3 months of end of follow-up. Bivariate analysis and multiple linear regression elucidated factors associated with poorer adherence.

RESULTS

Of 193 IBD patients, 132 (68.4%) had Crohn's disease. One hundred and thirty six (70.5%) patients received infliximab and 57 (29.5%) received vedolizumab with a median 13 [IQR 11-14] doses administered per patient over 2 years. Adherence according to CMG was similar between infliximab and vedolizumab groups (median 1.5% vs 1.2%, p = 0.31). In multiple linear regression analysis male sex, shorter IBD duration and clinic non-attendances were each associated with poorer adherence (Beta 4.69, 3.90, 3.56 respectively, p < 0.05) and objective disease remission was inversely associated with poorer adherence (Beta -3.27, p < 0.05).

CONCLUSION

There was a wide range of adherence to biologic infusions in this IBD cohort with poorer adherence associated with patient related factors. Conversely, objectively measured remission was strongly associated with adherence. This emphasises the need for targeted interventions to improve adherence and monitoring, and mitigate treatment delays.

Therapeutic drug monitoring in patients on biologics: lessons from gastroenterology

PURPOSE OF REVIEW

To give an overview on the role of therapeutic drug monitoring (TDM) of biologics in patients with inflammatory bowel disease (IBD).

RECENT FINDINGS

Numerous prospective exposure-response relationship studies and post-hoc analyses of randomized controlled trials (RCTs) show a positive correlation between biologic drug concentrations and favorable clinical outcomes in IBD. These studies also demonstrate that higher drug concentrations appear to be needed to achieve more stringent objective therapeutic outcomes. Reactive TDM rationalizes the management of primary nonresponse and secondary loss of response to antitumor necrosis factor (anti-TNF) therapy and is more cost-effective when compared with empiric dose optimization. Furthermore, recent data suggest that proactive TDM, with the goal of targeting a threshold drug concentration, is associated with better therapeutic outcomes when compared with empiric dose escalation and/or reactive TDM of infliximab or adalimumab. Finally, proactive TDM can also efficiently guide infliximab de-escalation or discontinuation in patients with IBD in remission.

SUMMARY

Reactive TDM is currently considered as standard of care, whereas proactive TDM is emerging as a new therapeutic strategy for better optimizing anti-TNF therapy in IBD. However, more data from prospective studies are needed before a wide implementation of TDM-based algorithms in real life clinical practice for newer biologics.

The Future of Precision Medicine

Precision medicine is an emerging framework to maximize therapeutic benefit by modifying the treatment for individual patients based on their variations in demographic, genomic, and environmental factors. In particular, "Pharmacogenomics" and "Therapeutic Drug Monitoring" are key elements of individualized drug treatment, staging Clinical Pharmacology at the forefront of precision medicine.