Design and conduct considerations for studies in patients with hepatic impairment

Opportunities and Challenges of Hepatic Impairment Physiologically Based Pharmacokinetic Modeling in Drug Development-An IQ Perspective

PBPK models are gaining special interest as a drug development tool to estimate the effect of intrinsic and extrinsic factors on drug pharmacokinetics. The IQ Consortium Clinical Pharmacology Organ Impairment Working Group conducted a survey across IQ Consortium member pharmaceutical companies to understand current practices on how PBPK is used in understanding the effect of hepatic impairment (HI) on drug disposition and its impact on clinical development. Responses from 21 participants indicated that most organizations (~86%) are already using PBPK models for HI assessment. The survey results indicate that PBPK models have been influential in optimizing the design of dedicated HI study with 57% of respondents using PBPK models to inform the design elements of dedicated HI studies, and the majority of these respondents using the PBPK model to support internal decision making regarding the HI study. Additionally, the PBPK model was used by 62% of the respondents to predict drug plasma protein binding. Despite common usage of the PBPK models by drug developers, 14.3% of the respondents discussed their PBPK modeling strategy with regulatory agencies with only two cases where the regulators accepted the PBPK model. In conclusion, although the use of PBPK models to support regulatory decisions regarding drug use in HI is currently limited, its future is promising, and the success of such models needs collaboration between regulators and drug developers to shrink the knowledge gap in the use of PBPK as an impactful tool for drug development in patients with HI.

Effects of Hepatic or Renal Impairment on Pharmacokinetics of Fruquintinib

Fruquintinib (FRUZAQLATM) is a highly selective tyrosine kinase inhibitor of all three vascular endothelial growth factor receptors (-1, -2, and -3). Two Phase 1, open-label, single-dose studies investigated the impact of hepatic or renal impairment on the pharmacokinetics and tolerability of fruquintinib. Participants with moderate renal impairment (creatinine clearance [CrCl] 30-59 mL/min; eight participants) and matched healthy controls (eight participants for each study) received fruquintinib 5 mg. Participants with moderate hepatic impairment (Child-Pugh B; eight participants) and severe renal impairment (CrCl 15-29 mL/min; eight participants) received fruquintinib 2 mg. Pharmacokinetic samples were collected over 240 h. Fruquintinib pharmacokinetics were similar between participants with moderate hepatic impairment and healthy controls; geometric mean ratios (GMRs) and 90% confidence intervals (CIs) for maximum plasma concentration (Cmax), area under the plasma concentration-time curve from 0 to time of last measurable concentration (AUC0-t), and AUC from 0 to infinity (AUC0-inf) were 1.04 (0.87-1.24), 0.89 (0.64-1.23), and 0.91 (0.66-1.26), respectively. Fruquintinib pharmacokinetics were similar between participants with severe or moderate renal impairment and healthy controls. Compared with healthy controls, the respective GMRs (90% CIs) for Cmax, AUC0-t, and AUC0-inf for participants with severe renal impairment were 0.89 (0.78-1.03), 0.97 (0.83-1.14), and 1.01 (0.85-1.19), and for participants with moderate renal impairment were 0.95 (0.78-1.15), 1.06 (0.89-1.26), and 1.07 (0.89-1.28). Fruquintinib was generally well tolerated. These results support fruquintinib use without dose adjustment (5 mg daily, 3 weeks on, and 1 week off) in patients with moderate hepatic impairment or moderate to severe renal impairment.

Effect of Hepatic Impairment or Renal Impairment on the Pharmacokinetics of Aficamten

BACKGROUND AND OBJECTIVE

Aficamten, a small-molecule, selective cardiac myosin inhibitor, is under development for the treatment of symptomatic obstructive hypertrophic cardiomyopathy (oHCM). Aficamten is primarily eliminated by hepatic metabolism with renal excretion playing a minor role. The objective of this investigation was to evaluate the pharmacokinetics (PK) of aficamten in moderate hepatic impairment or mild to moderate renal impairment to inform dosing recommendations in HCM patients with mild or moderate hepatic impairment or mild to moderate renal impairment.

METHODS

The impact of hepatic impairment on the PK of single-dose aficamten 20 mg was evaluated in a phase 1 single-dose, open-label, parallel-group study, in healthy participants with moderate (n = 8) hepatic impairment (Child-Pugh B classification) versus participants with normal hepatic function (n = 8). Safety was monitored throughout. The effect of renal impairment on aficamten PK was assessed using population PK (PopPK) modelling of phase 2/3 clinical data in patients with oHCM.

RESULTS

Aficamten PK was similar in participants with moderate hepatic impairment and those with normal hepatic function. No serious or severe treatment-emergent adverse events or clinically significant laboratory abnormalities were reported. There were no clinical meaningful differences in aficamten exposure in patients with oHCM with mild or moderate renal impairment and those with normal renal function.

CONCLUSIONS

No clinically relevant changes in aficamten PK were observed in participants with moderate hepatic impairment. Population PK analysis indicated mild or moderate renal impairment and had no statistically or clinically significant impact on aficamten PK in patients with oHCM. Aficamten dose adjustment may not be necessary in patients with mild or moderate hepatic or renal impairment.

Phase I Study to Evaluate the Effect of Hepatic Impairment on Pharmacokinetics and Safety of Tegoprazan, a Potassium Competitive Acid Blocker

INTRODUCTION

Tegoprazan is a potassium-competitive acid blocker, and its systemic exposure is presumably affected by hepatic clearance and bioavailability. This study aimed to investigate the effect of hepatic impairment (HI) on the safety and pharmacokinetics of tegoprazan and metabolite.

METHODS

An open-label, multicenter, parallel-group study was conducted in patients with mild (n = 8), moderate (n = 8) and severe (n = 1) HI according to the Child-Pugh classification as well as controls. Healthy subjects (n = 8) were matched to patients with the moderate category based on age, body mass index and sex. Blood and urine samples were obtained to evaluate the concentrations of tegoprazan and metabolite (M1) until 48 h after a single oral administration of 50 mg of tegoprazan.

RESULTS

The geometric mean ratio with a 90% confidence interval of maximum plasma concentration and area under the plasma concentration-time curve for tegoprazan in patients with impaired hepatic function compared to controls were 0.8228 (0.4997-1.3550) and 1.2264 (0.7447-2.0197) in the mild category, 1.0332 (0.6274-1.7015) and 1.7676 (1.0733-2.9109) in the moderate category, and 1.0699 (0.3713-3.0823) and 1.9567 (0.6792-5.6377) in the severe category. The half-life, apparent clearance, renal clearance, and fraction unbound to plasma protein were comparable across study groups. The plasma concentration of M1 increased and decreased faster in the normal group. Tegoprazan was generally well tolerated in patients with HI.

CONCLUSIONS

Systemic exposure to tegoprazan tended to be increased in subjects with HI. The difference between patients with mild HI and the controls was deemed not to require dose adjustment for tegoprazan.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifiers: NCT04494269 (31 Jul 2020).

Operating Characteristics of the Simulated Healthy Participant Approach in Impaired Clearance Studies

Minimizing harm is a cornerstone of ethical research practices. A drug that has undergone extensive clinical pharmacological testing in healthy participants (HPs) and a diverse selection of patients can be described with a sufficiently predictive population pharmacokinetic (PopPK) model. In impaired clearance trials, recruitment is minimized and underpowered for all but major exposure differences. Virtual HP arms have been reported to support similar conclusions to conventional impaired clearance studies, and further minimize potential harm of drug exposure without medical benefit by eliminating an arm of the study. However, the extent to which the conventional analysis of impairment studies compare to the simulation approach is unknown. Here we assess the operating characteristics of the virtual cohort approach along with the conventional approach through controlled simulations. These simulations included a simple, widely accessible PopPK model and several internal models that have been used in a previous meta-analysis of the virtual cohort approach. In the pairwise comparisons assessed, the virtual cohort simulation approach had greater power per sample size than the conventional approach and the same power under the null hypothesis. Given key methodological differences, it is recommended that the simulation and conventional approaches be treated as having approximately the same power under equivalent conditions. These results provide a strong justification for the use of the virtual cohort approach when an adequate PopPK model is available, minimizing unnecessary exposure to study drugs that will not benefit healthy study participants.

New Insights Into Hepatic Impairment (HI) Trials

Hepatic impairment (HI) trials are traditionally part of the clinical pharmacology development to assess the need for dose adaptation in people with impaired metabolic capacity due to their diseased liver. This review aimed at looking into the data from dedicated HI studies, cluster these data into various categories and connect the effect by HI with reported pharmacokinetics (PK) properties in order to identify patterns that may allow waiver, extrapolations, or adapted HI study designs. Based on a ratio ≥ 2 or ≤ 0.5 in AUC or Cmax between hepatically impaired participants/healthy controls these were considered "positive" or "negative". In case of more than one HI severity stratum per compound included in the HI trial, the comparison of the AUC ratios for mild, moderate, or severe HI were used to investigate the increase across HI categories. For the in total 436 hits, relevant PK information could be retrieved for 273 compounds of which 199 were categorized negative, 69 positive ups and 5 positive downs. Fourteen out of 69 compounds demonstrated a steep increase in the AUC ratios from mild to severe HI. Compounds demonstrating a steep increase typically had a high plasma protein binding of > 95%, high volume of distribution, lower absolute bioavailability, minor elimination via the kidneys, were predominantly metabolized by CYP3A4 or CYP2D6 and the majority of these compounds were substrates of OATP1B1. While for compounds with steep increase studies in all severity strata may be warranted they may also offer the potential to estimate the appropriate doses in an HI trial. On the other hand, for compounds with slow or no increase across HI severity strata, reduced HI trials may be justified, e.g. only testing PK in moderate HI.

Getting the Dose Right in Drug Development for Rare Diseases: Barriers and Enablers

In the relentless pursuit of optimizing drug development, the intricate process of determining the ideal dosage unfolds. This involves "dose-finding" studies, crucial for providing insights into subsequent registration trials. However, the challenges intensify when tackling rare diseases. The complexity arises from poorly understood pathophysiologies, scarcity of appropriate animal models, and limited natural history understanding. The inherent heterogeneity, coupled with challenges in defining clinical end points, poses substantial challenges, hindering the utility of available data. The small affected population, low disease awareness, and restricted healthcare access compound the difficulty in conducting dose-finding studies. This white paper delves into critical dose selection aspects, focusing on key therapeutic areas, such as oncology, neurology, hepatology, metabolic rare diseases. It also explores dose selection challenges posed by pediatric rare diseases as well as novel modalities, including enzyme replacement therapies, cell and gene therapies, and oligonucleotides. Several examples emphasize the pivotal role of clinical pharmacology in navigating the complexities associated with these diseases and emerging treatment modalities.

Effect of Renal and Hepatic Impairment on the Pharmacokinetics of Pritelivir and Its Metabolites

Two trials were performed to evaluate the effect of renal and hepatic impairment on the pharmacokinetics of pritelivir and its metabolites. The renal impairment trial included subjects with mild, moderate, and severe impairment, while the hepatic impairment trial included subjects with moderate impairment. Both trials recruited a matched control group of healthy subjects. Following a single oral dose of 100 mg of pritelivir, mild and moderate renal impairment and moderate hepatic impairment did not have a clinically relevant effect on the pharmacokinetics of pritelivir. In subjects with severe renal impairment, pritelivir exposure (area under the plasma concentration-time curve from time 0 to infinity (AUC0- inf) was 57% higher compared with controls. Pritelivir plasma protein binding was similar in subjects and controls with renal impairment, while the free fraction was higher in subjects with moderate hepatic impairment, increasing unbound pritelivir exposure by 23%. For the metabolites pyridinyl phenyl acetic acid (PPA), amino thiazole sulfonamide (ATS), and PPA-acyl glucuronide, generally higher exposure was observed with increasing degree of renal impairment (ie, moderate to severe), but not with mild impairment. A modest effect of moderate hepatic impairment was observed for PPA and ATS. Pritelivir was safe and well tolerated in healthy subjects and subjects with renal or hepatic impairment.

Single‑Dose Pharmacokinetics and Safety of the Oral Galectin‑3 Inhibitor, Selvigaltin (GB1211), in Participants with Hepatic Impairment

BACKGROUND AND OBJECTIVES

Selvigaltin (GB1211), an orally available small molecule galectin-3 inhibitor developed as a treatment for liver fibrosis and cirrhosis, was evaluated to assess the effect of hepatic impairment on its pharmacokinetics and safety to address regulatory requirements.

METHODS

GULLIVER-2 was a Phase Ib/IIa three-part study. Parts 1 and 3 had single-dose, open-label designs assessing pharmacokinetics (plasma [total and unbound] and urine), safety, and tolerability of 100 mg oral selvigaltin in participants with moderate (Child-Pugh B, Part 1) or severe (Child-Pugh C, Part 3) hepatic impairment, compared with healthy-matched participants (n = 6 each).

RESULTS

All participants received selvigaltin and completed the study. No adverse events were reported. The median time to reach maximum total plasma concentration following drug administration was of 3.49 and 4.00 h post-dose for Child-Pugh B and C participants, respectively; comparable with controls. Total plasma exposure was higher for participants with hepatic impairment compared with controls. Whilst maximum plasma concentration (Cmax) was unaffected in Child-Pugh B participants, area under the plasma concentration-time curve from time zero to infinity (AUC∞) increased by ~ 1.7-fold compared with controls, and half-life was prolonged (geometric mean 28.15 vs 16.38 h). In Child-Pugh C participants, Cmax increased by ~ 1.3-fold, AUC∞ increased by ~ 1.5-fold, and half-life was prolonged (21.05 vs 16.14 h). No trend was observed in plasma unbound fractions or urinary excretion of unchanged selvigaltin in either group.

CONCLUSION

Hepatic impairment increased selvigaltin exposure without safety concerns. These data can inform dose recommendations for future clinical programmes.

TRIAL REGISTRATION

Clinicaltrials.gov NCT05009680.

Treatment of Pain in Cirrhosis: Advice to Caregivers of Those with Rock Livers

PURPOSE

When one considers the significant role of the liver in medication absorption and metabolism, clinicians must appreciate the important ramifications for medication dosing and monitoring in patients with cirrhosis. For many medications, dose adjustments may be necessary to minimize toxicities or avoid adverse effects from drug accumulation. Clinicians could be well served if they can understand in some detail how pharmacokinetic properties are altered in cirrhosis.

METHODS

A PubMed search of the English medical literature starting with 1980 using keywords cirrhosis, pain management, and analgesics was performed, and additional papers were found using references from the first round of papers.

FINDINGS

Patients with cirrhosis often have significant reductions in first-pass metabolism, altered volumes of distribution, and marked reductions in both renal and hepatic elimination of drugs. These factors may contribute to much higher levels of drug exposure compared to the general population. In terms of drug dosing, FDA labeling is often ambiguous and even incongruous with observed pharmacokinetic changes.

IMPLICATIONS

This article may provide guidance for clinicians to optimize pain management in people living with cirrhosis.

KEY MESSAGE

Current FDA labeling for dosing analgesic drugs in patients with cirrhosis is either vague or not consistent with findings from newer pharmacokinetic research. With this review, we hope to provide insight and guidance to clinicians on how to dose-adjust medications commonly utilized in pain management in these patients.

Reduced hepatic impairment study to evaluate pharmacokinetics and safety of zavegepant and to inform dosing recommendation for hepatic impairment

Zavegepant, a high-affinity, selective, small-molecule calcitonin gene-related peptide (CGRP) receptor antagonist, is approved in the United States for acute treatment of migraine in adults. The effects of moderate hepatic impairment (8 participants with Child-Pugh score 7-9 points) on the pharmacokinetics of a single 10-mg intranasal dose of zavegepant versus eight matched participants with normal hepatic function were evaluated in a phase I study. Pharmacokinetic sampling determined total and unbound plasma zavegepant concentrations. Moderate hepatic impairment increased the exposure of total zavegepant (~2-fold increase in AUC0-inf and 16% increase in Cmax) versus normal hepatic function, which is not considered clinically meaningful. The geometric least squares mean ratios (moderate impairment/normal) of plasma zavegepant AUC0-inf and Cmax were 193% (90% confidence interval [CI]: 112, 333; p = 0.051) and 116% (90% CI: 69, 195; p = 0.630), respectively. The geometric mean fraction unbound of zavegepant was similar for participants with moderate hepatic impairment (0.13; coefficient of variation [CV] 13.71%) versus those with normal hepatic function (0.11; CV 21.43%). Similar exposure findings were observed with unbound zavegepant versus normal hepatic function (~2.3-fold increase in AUC0-inf and 39% increase in Cmax). One treatment-emergent adverse event (mild, treatment-related headache) was reported in a participant with normal hepatic function. No dosage adjustment of intranasal zavegepant is required in adults with mild or moderate hepatic impairment.

Simulating Healthy Participant Pharmacokinetics for Renal and Hepatic Impairment Studies: Retrospective Assessment of the Approach

The recruitment of a parallel, healthy participants (HPs) arm in renal and hepatic impairment (RI and HI) studies is a common strategy to assess differences in pharmacokinetics. Limitations in this approach include the underpowered estimate of exposure differences and the use of the drug in a population for which there is no benefit. Recently, a method was published by Purohit et. al. (2023) that leveraged prior population pharmacokinetic (PopPK) modeling-based simulation to infer the distribution of exposure ratios between the RI/HI arms and HPs. The approach was successful, but it was a single example with a robust model having several iterations of development and fitting to extensive HP data. To test in more studies and models at different stages of development, our catalogue of RI/HI studies was searched, and those with suitable properties and from programs with available models were analyzed with the simulation approach. There were 9 studies included in the analysis. Most studies were associated with models that would have been available at the time (ATT) of the study, and all had a current, final model. For 3 studies, the HP PK was not predicted well by the ATT (2) or final (1) models. In comparison to conventional analysis of variance (ANOVA), the simulation approach provided similar point estimates and confidence intervals of exposure ratios. This PopPK based approach can be considered as a method of choice in situations where the simulation of HP data would not be an extrapolation, and when no other complicating factors are present.

Feasibility of Using Population Pharmacokinetics-Based Virtual Control Groups in Organ Impairment Studies

This work aimed to assess the feasibility of using population pharmacokinetics (popPK) to generate virtual healthy control groups in organ impairment studies. Data from 11 organ impairment studies containing 18 organ impairment arms and 13 healthy control groups across 7 drugs were analyzed. Area under the concentration-time curve (AUC) and maximum concentration (Cmax) were calculated from popPK-simulated individual concentration-time profiles for participants in the healthy control groups, accounting for the participant's specific covariate(s) (N = 1000 replicates). The AUC and Cmax geometric mean ratios (GMRs; simulated healthy control/observed healthy control and observed organ impairment/simulated healthy control) were calculated. The simulated healthy control group geometric mean exposures were within 30% of the observed geometric mean exposures in 8 of the 11 studies (73%). The number of organ impairment arms for which the observed GMR (observed organ impairment/observed healthy control) and median of simulation-based GMRs (observed organ impairment/simulated healthy control) for AUC and Cmax being within the same fold change were 12 (67%) and 13 (72%) arms, respectively. The number of organ impairment arms for which the median of simulation-based AUC and Cmax GMRs were within the 90% confidence interval of the observed GMRs were 14 (72%) and 15 (83%), respectively. Poor concordance was observed for 1 drug (3 arms), where healthy participants' data were not incorporated in the popPK model. This work supports using popPK-based virtual control groups in organ impairment studies. Subsequent work should aim to establish best practices for constructing popPK-based virtual control groups.

Effect of changes in metabolic enzymes and transporters on drug metabolism in the context of liver disease: Impact on pharmacokinetics and drug-drug interactions

Changes in the pharmacokinetic and resulting pharmacodynamic properties of drugs are common in many chronic liver diseases, leading to adverse effects, drug interactions and increased risk of over- or underdosing of medications. Structural and functional hepatic impairment can have major effects on drug metabolism and transport. This review summarizes research on the functional changes in phase I and II metabolic enzymes and in transport proteins in patients with metabolic diseases such as type 2 diabetes, metabolic dysfunction-associated steatotic liver disease, metabolic dysfunction-associated steatohepatitis and cirrhosis, providing a clinical perspective on how these changes affect drug uptake and metabolism. Generally, a decrease in expression and/or activity of many enzymes of the cytochrome P450 family (e.g. CYP2E1 and CYP3A4), and of influx and efflux transporters (e.g. organic anion-transporting polypeptide [OATP]1B1, OATP2B1, OAT2 and bile salt export pump), has been recently documented in patients with liver disease. Decreased enzyme levels often correlate with increased severity of chronic liver disease. In subjects with hepatic impairment, there is potential for strong alterations of drug pharmacokinetics due to reduced absorption, increased volume of distribution, metabolism and extraction. Due to the altered pharmacokinetics, specific drug-drug interactions are also a potential issue to consider in patients with liver disease. Given the huge burden of liver disease in western societies, there is a need to improve awareness among all healthcare professionals and patients with liver disease to ensure appropriate drug prescriptions.

Pharmacokinetics, safety, and tolerability of BMS-986263, a lipid nanoparticle containing HSP47 siRNA, in participants with hepatic impairment

BMS-986263 is a retinoid-conjugated lipid nanoparticle delivering small interfering RNA designed to inhibit synthesis of HSP47 protein, a collagen-specific chaperone protein involved in fibrosis development. This is a phase I, open-label, two-part study evaluating pharmacokinetics and safety of BMS-986263 in participants with hepatic impairment (HI). Part 1 (n = 24) of this study enrolled two cohorts with mild and moderate HI and a separate cohort of age- and body mass index (BMI)-matched participants with normal hepatic function. Part 2 enrolled eight participants with severe HI and eight age- and BMI-matched participants with normal hepatic function. All participants received a single intravenous 90 mg BMS-986263 infusion. Compared with normal-matched participants, geometric mean area under the plasma concentration-time curve time zero to the time of the last quantifiable concentration (AUC(0-T) ) and AUC from zero to infinity (AUC(INF) ) of HSP47 siRNA were similar in participants with mild HI and 34% and 163% greater in those with moderate and severe HI, respectively, whereas the maximum plasma concentration was ~25% lower in mild and moderate HI groups but 58% higher in the severe HI group than in the normal group. Adverse events were reported by two of eight, four of eight, and three of eight participants with mild, moderate, or severe HI, respectively; none were reported in the normal-matched group. Overall, single-dose BMS-986263 was generally safe and well-tolerated and dose adjustment is not considered necessary for participants with mild or moderate HI. Although available data do not indicate that dose adjustment should be performed in patients with severe HI; the optimal posology of BMS-986263 in patients with severe HI may be determined later in its clinical development when additional data to establish exposure-safety/efficacy relationship becomes available.

Pharmacokinetics of JNJ-73763989 and JNJ-56136379 (Bersacapavir) in Participants With Moderate Hepatic Impairment

JNJ-73763989 is comprised of 2 short interfering RNAs (siRNAs), JNJ-73763976 and JNJ-73763924, that target hepatitis B virus (HBV) mRNAs for degradation, thereby inhibiting HBV replication. JNJ-56136379 is a capsid assembly modulator that inhibits HBV replication by inducing the formation of empty capsids (CAM-E). In 2 phase 1, open-label, non-randomized, single-center studies, the single-dose pharmacokinetics, safety, and tolerability of JNJ-73763989 or JNJ-56136379 were assessed in participants with moderate hepatic impairment (Child-Pugh Class B) versus participants with normal liver function. Participants in both studies received a single subcutaneous dose of JNJ-73763989 200 mg or oral JNJ-56136379 250 mg, followed by an evaluation of plasma pharmacokinetic parameters and safety assessments. Plasma exposure to JNJ-73763976, JNJ-73763924, and JNJ-56136379 was 1.3- to 1.4-, 1.8- to 2.2-, and 1.1- to 1.3-fold higher in participants with moderate hepatic impairment versus participants with normal liver function; however, these increases were not considered clinically relevant. Both drugs were well tolerated and safe, with 7 (21.9%) participants experiencing 1 or more treatment-emergent adverse events, 3 of which were related to JNJ-56136379. Overall, the plasma exposures of JNJ-73763989 and JNJ-56136379 were higher in participants with moderate hepatic impairment, but both were well tolerated. Further studies are needed to evaluate the effect of hepatic impairment under multiple-dose administration.