Application of Physiologically Based Pharmacokinetic Modeling to Predict Drug Exposure and Support Dosing Recommendations for Potential Drug-Drug Interactions or in Special Populations: An Example Using Tofacitinib

Conventional vs Mechanistic IVIVC: A Comparative Study in Establishing Dissolution Safe Space for Extended Release Formulations

The use of in vitro-in vivo correlation (IVIVC) for extended release oral dosage forms is an important technique that can avoid potential clinical studies. IVIVC has been a topic of discussion over the past two decades since the inception of USFDA guidance. It has been routinely used for biowaivers, establishment of dissolution safe space and clinically relevant dissolution specifications, for supporting site transfers, scale-up and post approval changes. Although conventional or mathematical IVIVC is routinely used, other approach such as mechanistic IVIVC can be of attractive choice as it integrates all the physiological aspects. In the present study, we have performed comparative evaluation of mechanistic and conventional IVIVC for establishment of dissolution safe space using divalproex sodium and tofacitinib extended release formulations as case examples. Conventional IVIVC was established using Phoenix and mechanistic IVIVC was set up using Gastroplus physiologically based biopharmaceutics model (PBBM). Virtual dissolution profiles with varying release rates were constructed around target dissolution profile using Weibull function. After internal and external validation, the virtual dissolution profiles were integrated into mechanistic and conventional IVIVC and safe space was established by absolute error and T/R ratio's methods. The results suggest that mechanistic IVIVC yielded wider safe space as compared to conventional IVIVC. The results suggest that a mechanistic approach of establishing IVIVC may be a flexible approach as it integrates physiological aspects. These findings suggest that mechanistic IVIVC has wider potential as compared to conventional IVIVC to gain wider dissolution safe space and thus can avoid potential clinical studies.

Integrating Clinical Variability into PBPK Models for Virtual Bioequivalence of Single and Multiple Doses of Tofacitinib Modified-Release Dosage Form

Tofacitinib is a potent, selective inhibitor of the Janus kinase (JAK) family of kinases with a high degree of selectivity within the human genome's set of protein kinases. Currently approved formulations for tofacitinib citrate are immediate-release (IR) tablets, modified-release (MR) tablets, and IR solution. A once daily MR microsphere formulation was developed for use in pediatric patients. Demonstration of bioequivalence (BE) between the 10 mg once daily (q.d.) MR microsphere formulation and 5 mg twice daily (b.i.d.) IR solution is needed to enable the exposure-response analyses-based bridging to support regulatory approval. To assess BE between MR microsphere and IR solution, an innovative approach was utilized with physiologically-based pharmacokinetic (PBPK) virtual BE trials (VBE) in lieu of a clinical BE trial. A PBPK model was developed to characterize the absorption of different formulations of tofacitinib using Simcyp ADAM module. VBE trials were conducted by simulating PK profiles using the verified PBPK model and integrating the clinically observed intrasubject coefficient of variation (ICV) where BE was assessed with a predetermined sample size and prespecified criteria. The VBE trials demonstrated BE between IR solution 5 mg b.i.d. and MR microsphere 10 mg q.d. after a single dose on day 1 and after multiple doses on day 5. This research presents an innovative approach that incorporates clinically observed ICV in PBPK model-based VBE trials, which could reduce unnecessary drug exposure to healthy volunteers and streamline new formulation development strategies.

Safety of Janus kinase inhibitors compared to biological DMARDs in patients with rheumatoid arthritis and renal impairment: the ANSWER cohort study

Data on the safety of Janus kinase inhibitors (JAKis) in patients with renal impairment are lacking. This study aimed to investigate the safety of JAKis compared to biological (b) DMARDs in patients with rheumatoid arthritis (RA) and renal impairment. We used a multi-centre observational registry of patients with RA in Japan (the ANSWER cohort). We assessed the drug retention rates of b/targeted synthetic DMARDs with different modes of action (tumour necrosis factor inhibitors (TNFis), immunoglobulins fused with cytotoxic T-lymphocyte antigen (CTLA-4-Ig), interleukin-6 receptor inhibitors (IL-6Ris), and JAKis) in patients with RA stratified by pre-treatment estimated glomerular filtration rate (eGFR) levels. The time to discontinuation of bDMARDs or JAKis was analysed using a multivariate Cox proportional hazards model This study included 3775 patients, who were classified into three groups (the normal group (eGFR ≥ 60 mL/min/1.73 m2): 2893 patients; CKDa group (eGFR 45-60 mL/min/1.73 m2): 551; and CKDb group (eGFR < 45 mL/min/1.73 m2): 331). In the CKDb group, the 12-month drug retention rate due to adverse events (AE) was the lowest in patients treated with JAKi (TNFi: 93.1%; IL-6Ri: 94.1%; CTLA-4-Ig: 92.3%; JAKi: 75.1%). In the normal and CKDa groups, drug retention rates due to AE were similar among patients treated with bDMARDs and JAKi. In contrast, drug retention rates due to inefficacy were similar between bDMARDs and JAKis in all groups. In the Cox-proportional model, in the CKDb group, TNFi, IL-6Ri, and CTLA-4-Ig showed lower incidence of drug discontinuation due to AE than JAKis (TNFi: hazard ratio = 0.23 (95% confidence interval 0.09-0.61), IL-6Ri: 0.34 (0.14-0.81), CTLA-4-Ig: 0.36 (0.15-0.89)). JAKis showed the lowest drug retention due to AE in patients with moderate-to-severe and severe renal impairment (eGFR < 45 mL/min/1.73 m2). Physicians should pay more attention to renal function when using JAKis than when using bDMARDs.

Ulcerative Colitis in Adulthood and in Older Patients: Same Disease, Same Outcome, Same Risks?

The number of patients with inflammatory bowel disease (IBD) approaching an older age, together with the number of over-60-year-old patients newly diagnosed with IBD, is steadily increasing, reaching 25% of all patients. The present review focuses on late-onset ulcerative colitis (UC) and its initial disease course in comparison with that observed in younger adults in terms of extension at onset and the risk of proximal disease progression, medical treatment, surgery and hospitalization in the first years after diagnosis. We summarize the clues pointing to a milder disease course in a population which frequently presents major frailty due to comorbidities. With increasing age and thus increasing comorbidities, medical and surgical therapies frequently represent a challenge for treating physicians. The response, persistence, and risks of adverse events of conventional therapies indicated for late onset/older UC patients are examined, emphasizing the risks in this particular population, who are still being treated with prolonged corticosteroid therapy. Finally, we concentrate on data on biotechnological agents for which older patients were mostly excluded from pivotal trials. Real-life data from newer agents such as vedolizumab and ustekinumab show encouraging efficacy and safety profiles in the population of older UC patients.

A Systematic Review on Disease-Drug-Drug Interactions with immunomodulating drugs: A Critical Appraisal of Risk Assessment and Drug Labelling

Aim

Use of immunomodulating therapeutics for immune‐mediated inflammatory diseases may cause disease‐drug‐drug interactions (DDDIs) by reversing inflammation‐driven alterations in the metabolic capacity of cytochrome P450 enzymes. European Medicine Agency (EMA) and US Food and Drug Administration (FDA) guidelines from 2007 recommend that the DDDI potential of therapeutic proteins should be assessed. This systematic analysis aimed to characterize the available DDDI trials with immunomodulatory drugs, experimental evidence for a DDDI risk and reported DDDI risk information in FDA/EMA approved drug labelling.

Method

For this systematic review, the EMA list of European Public Assessment Reports of human medicine was used to select immunomodulating monoclonal antibodies (mAbs) and tyrosine kinase inhibitors (TKIs) marketed after 2007 at risk for a DDDI. Selected drugs were included in PubMed and Embase searches to extract reported interaction studies. The Summary of Product Characteristics (SPCs) and the United States Prescribing Information (USPIs) were subsequently used for analysis of DDDI risk descriptions.

Results

Clinical interaction studies to evaluate DDDI risks were performed for 12 of the 24 mAbs (50%) and for none of the TKIs. Four studies identified a DDDI risk, of which three were studies with interleukin‐6 (IL‐6) neutralizing mAbs. Based on (non)clinical data, a DDDI risk was reported in 32% of the SPCs and in 60% of the USPIs. The EMA/FDA documentation aligned with the DDDI risk potential in 35% of the 20 cases.

Conclusion

This systematic review reinforces that the risk for DDDI by immunomodulating drugs is target‐ and disease‐specific. Drug labelling information designates the greatest DDDI risk to mAbs that neutralize the effects of IL‐6, Tumor Necrosis Factor alfa (TNF‐α) and interleukin‐1 bèta (IL‐1β) in diseases with systemic inflammation.

Physiologically-Based Pharmacokinetic Modelling to Investigate Baricitinib and Tofacitinib Dosing Recommendations for COVID-19 in Geriatrics

Janus kinase (JAK) inhibitors baricitinib and tofacitinib are recommended by the US National Institutes of Health as immunomodulatory drugs for coronavirus disease 2019 (COVID-19) treatment. In addition, baricitinib has recently received Emergency Use Authorization from the US Food and Drug Administration, although the instruction provided dosing information only for adults. Geriatrics with organ dysfunction are one of the most vulnerable cohorts when combating the pandemic. The aim of the present work was to evaluate current dosing strategies of baricitinib and tofacitinib for potential COVID-19 treatment for White and Chinese geriatric patients with chronic renal impairment. An established physiologically-based pharmacokinetic (PBPK) modeling framework for age-dependent simulations was utilized. PBPK drug models adopted from literature were first verified. Several population models representing different age groups, ethnicities, and stages of renal impairment were used for prospective simulations. Notwithstanding the increase in systemic exposure of both drugs resulting from renal dysfunction was more pronounced for geriatrics than general White populations, our simulations confirmed their current dosage adjustments based on renal functions are broadly adequate. The exception being White older subjects with mild renal impairment where current recommendation of 4 mg baricitinib yielded a 2.31-fold increase in systemic exposure, and reduction to 2 mg could mitigate the potential risk to an acceptable 1.15-fold. Comparable relationships between systemic exposure and renal dysfunction were observed for both drugs in the Chinese population. In summary, PBPK modeling of both JAK inhibitors supports the rational and prudent dose adjustments of these COVID-19 therapeutics among adult patients of different age groups and renal functions.

Efficacy and Safety of Ertugliflozin in Type 2 Diabetes: A Systematic Review and Meta-Analysis

Objective: To evaluate the efficacy and safety of ertugliflozin in patients with type 2 diabetes.

Methods: MEDLINE, EMBASE, and Cochrane Library were searched (July 31, 2021) for phase II/III randomized clinical trials, which reported the efficacy and safety of ertugliflozin. Continuous variables were calculated as weighted mean difference (WMD) and associated 95% confidence intervals (CIs); dichotomous data were expressed as risk ratios (RRs) with 95% CIs.

Results: Nine randomized clinical trials including 5638 type 2 diabetes patients were included. For efficacy, ertugliflozin significantly reduced HbA1c (%) (WMD −0.452%; 95% CI −0.774 to −0.129), fasting plasma glucose (FPG) (WMD −0.870 mmol/L; 95% CI −1.418 to −0.322), body weight (WMD −1.774 kg; 95% CI −2.601 to −0.946), and blood pressure levels (systolic blood pressure: WMD −2.572 mmHg; 95% CI −3.573 to −1.571 and diastolic blood pressure: WMD −1.152 mmHg; 95% CI −2.002 to −0.303) compared with placebo and other hypoglycaemic agents. Compared with placebo, ertugliflozin was superior in reducing HbA1c (%) (WMD −0.641%) and FPG (WMD −1.249 mmol/L). And compared with active agents, ertugliflozin also could decrease HbA1c by 0.215% and FPG by 0.266 mmol/L. The interactive effect between different controls was significant (Pinteraction of 0.039). For safety, similar to other sodium-glucose cotransporter type-2 inhibitors, ertugliflozin mainly increased the risk of genital mycotic infection (RR: 4.004; 95% CI 2.504–6.402). There was no significant difference in the incidence of any adverse events (AEs), AEs related to study drug, serious AEs, deaths, and discontinuations due to AEs. Results were consistent with the most primary outcomes in subgroups analysis and sensitivity analysis.

Conclusion: Ertugliflozin was relatively effective and tolerated in patients with type 2 diabetes compared with placebo or other hypoglycaemic agents, except for a high risk of genital mycotic infection.

Systematic Review Registration: (ClinicalTrials.gov), identifier (CRD42020206356).

Review article: time to revisit Child-Pugh score as the basis for predicting drug clearance in hepatic impairment

BACKGROUND

Prescription information for many drugs entering the market lacks dosage guidance for hepatic impairment. Dedicated studies for assessing the fate of drugs in hepatic impairment commonly stratify patients using Child-Pugh score. Child-Pugh is a prognostic clinical score with limitations in reflecting the liver's metabolic capacity.

AIMS

To demonstrate the need for better drug dosing approaches in hepatic impairment, summarise the current status, identify knowledge gaps related to drug kinetic parameters in hepatic impairment, propose solutions for predicting the liver disease impact on drug exposure and discuss barriers to dosing guidance in those patients.

METHODS

Relevant reports on dosage adjustment in hepatic impairment were analysed concerning the prediction of the impairment impact on drug kinetics using physiologically-based pharmacokinetic (PBPK) modelling.

RESULTS

PBPK models are suggested as a potential framework to understand drug clearance changes in hepatic impairment. Quantifying changes in abundance and activity of drug-metabolising enzymes and transporters, understanding the impact of shunting, and accounting for interindividual variations in drug absorption could help in extending the success of these models in hepatically-impaired populations. These variables might not correlate with Child-Pugh score as a whole. Therefore, new metabolic activity markers, imaging techniques and other scoring systems are proposed to either support or substitute Child-Pugh score.

CONCLUSIONS

Many physiological changes in hepatic impairment determining the fate of drugs do not necessarily correlate with Child-Pugh score. Quantifying these changes in individual patients is essential in future hepatic impairment studies. Further studies assessing Child-Pugh alternatives are recommended to allow better prediction of drug exposure.