Evaluation of hepatic impairment dosing recommendations in FDA-approved product labels

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.

Drug transporters in drug disposition - the year 2022 in review

On behalf of all the authors, I am pleased to share our third annual review on drug transporter science with an emphasis on articles published and deemed influential in signifying drug transporters' role in drug disposition in the year 2022. As the drug transporter field is rapidly evolving several key findings were noted including promising endogenous biomarkers, rhythmic activity, IVIVE approaches in transporter-mediated clearance, new modality interaction, and transporter effect on gut microbiome. As identified previously (Chothe et Cal. 2021, 2022) the goal of this review is to highlight key findings without a comprehensive overview of each article and to this end, each coauthor independently selected 1-3 peer-reviewed articles published or available online in the year 2022 (Table 1). Each article is summarized in synopsis and commentary with unbiased viewpoints by each coauthor. We strongly encourage readers to consult original articles for specifics of the study. Finally, I would like to thank all coauthors for their continued support in writing this annual review on drug transporters and invite anyone interested in contributing to future versions of this review.

Effect of Hepatic Impairment on OATP1B Activity: Quantitative Pharmacokinetic Analysis of Endogenous Biomarker and Substrate Drugs

Hepatic impairment (HI) is known to modulate drug disposition and may lead to elevated plasma exposure. The aim of this study was to quantitate the in vivo OATP1B-mediated hepatic uptake activity in populations with varying degrees of HI. First, we measured baseline levels of plasma coproporphyrin-I, an endogenous OATP1B biomarker, in an open-label, parallel cohort study in adult subjects with normal liver function and mild, moderate, and severe HI (n = 24, 6/cohort). The geometric mean plasma concentrations of coproporphyrin-I were 1.66-fold, 2.81-fold (P < 0.05), and 7.78-fold (P < 0.0001) higher in mild, moderate, and severe impairment than those healthy controls. Second, we developed a dataset of 21 OATP1B substrate drugs with HI data extracted from literature. Median disease-to-healthy plasma area under the curve (AUC) ratios for substrate drugs were ~ 1.4, 3.0, and 6.4 for mild, moderate, and severe HI, respectively. Additionally, significant linear relationship was noted between AUC ratios of substrate drugs without and with co-administration of rifampin, a prototypic OATP1B inhibitor, and AUC ratios in moderate (P < 0.01) and severe (P < 0.001) HI. Third, a physiologically-based pharmacokinetic model analysis was conducted with 10 substrate drugs following estimation of relative OATP1B functional activity in virtual disease population models using coproporphyrin-I data and verification of substrate models with rifampin drug-drug interaction data. This approach adequately predicted plasma AUC change particularly in moderate (9 of 10 within 2-fold) and severe (5 of 5 within 2-fold) HI. Collective findings indicate progressive reduction, by as much as 90-92%, in OATP1B activity in the HI population.

Expert Consensus on Diagnosis and Treatment of End-Stage Liver Disease Complicated with Infections

Abstract

End-stage liver disease (ESLD) is a life-threatening clinical syndrome that markedly increases mortality in patients with infections. In patients with ESLD, infections can induce or aggravate the occurrence of liver decompensation. Consequently, infections are among the most common complications of disease progression. There is a lack of working procedure for early diagnosis and appropriate management for patients with ESLD complicated by infections as well as local and international guidelines or consensus. This consensus assembled up-to-date knowledge and experience across Chinese colleagues, providing data on principles as well as working procedures for the diagnosis and treatment of patients with ESLD complicated by infections.

Inconsistencies and Ambiguities in Liver-Disease-Related Contraindications-A Systematic Analysis of SmPCs/PI of Major Drug Markets

Liver disease is a common condition worldwide that can cause alterations in drug disposition and susceptibility to drug toxicities, with increased risk of adverse drug reactions. European Summaries of Product Characteristics (SmPCs) and United States Prescribing Information (US PI) should therefore be comprehensible to prescribers regarding their liver-associated contraindications to ensure safe prescribing. This study aimed to evaluate the ambiguity of terminology used in communicating liver-associated absolute contraindications in SmPCs/PI of commonly prescribed drugs in four major drug markets (Germany, Switzerland, the United Kingdom, and the United States) by assigning wordings to different categories and analyzing their clinical comprehensibility. For US PI, 79% did not contain liver-related contraindications, compared to 2, 13, and 6% of German, Swiss, and British SmPCs, respectively. Study findings indicate that out of 228 examined SmPCs/PI containing liver-related contraindications, 77, 79, 76, and 52% contained unclear wording in the German, Swiss, British, and American drug market, respectively. Only 40% (German), 52% (Swiss), 39% (British), and 29% (American) of SmPCs/PI included terms with explicit wording. Including more precise statements in SmPCs/PI based on laboratory parameters (such as albumin) or scores (e.g., the Child–Pugh score) to objectify the severity of liver disease may improve the clarity of SmPCs/PI and the safety of drug prescription.

Single-Dose Pharmacokinetics and Safety of Ubrogepant in Adults With Hepatic Impairment: Results From an Open-Label, Phase 1 Trial

Ubrogepant is an oral calcitonin gene–related peptide receptor antagonist approved for the treatment of acute migraine headaches. Ubrogepant demonstrated efficacy and safety in 2 pivotal phase 3 studies (N = 2240) that led to its approval. Here, we report the pharmacokinetics and safety results from a phase 1 study in which participants with severe (n = 4), moderate (n = 8), or mild (n = 8) hepatic impairment and matched participants with normal hepatic function (n = 8) were administered a single dose of 100 mg of ubrogepant. Twenty‐eight participants aged 36 to 70 years were enrolled and completed the study. In participants with mild, moderate, or severe hepatic impairment, ubrogepant systemic exposure (area under the plasma concentration–time curve) increased by 7%, 52%, and 115%, respectively, compared with participants with normal hepatic function (≈1600 ng • h/mL). Peak exposure increased by 1%, 18%, and 26%, respectively, in participants with mild, moderate, or severe hepatic impairment compared to those with normal hepatic function (≈400 ng/mL). Plasma protein binding did not change significantly across groups. No dose adjustment is recommended for patients with mild or moderate hepatic impairment. Dose adjustment (50 mg) is recommended for patients with severe hepatic impairment. Single doses of ubrogepant 100 mg were safe, and all the enrolled participants, regardless of hepatic function, completed the study.

Pharmacokinetics and Safety of Ranirestat in Patients With Hepatic Impairment

Ranirestat is an aldose reductase inhibitor hypothesized to improve diabetic neuropathy. An open-label, single-dose, parallel-group study was conducted to compare pharmacokinetic (PK) characteristics of an oral dose of ranirestat across subjects with normal hepatic function and patients with mild and moderate hepatic impairment because ranirestat is expected to be used by patients with diabetes mellitus, possibly including those with hepatic impairment. To evaluate the necessity for dose adjustment, PK profiles and tolerability were studied at the dose of 40 mg, the expected optimal clinical dose in patients with diabetic neuropathy and normal hepatic function. In total, 20 subjects, including 5, 10, and 5 subjects with normal hepatic function, mild hepatic impairment, and moderate hepatic impairment, respectively, completed the study. Serial PK sampling was conducted up to 504 hours, and PK parameters were calculated and compared between healthy subjects and patients with mild or moderate hepatic impairment. The geometric mean ratios of peak concentration and area under the concentration-time curve in patients with mild hepatic impairment (90%CI) were 86.7% (55.3% to 135.9%) and 84.7% (68.5% to 104.8%), respectively. The values in patients with moderate hepatic impairment were 81.3% (48.8% to 135.5%) and 91.7% (72.1% to 116.7%), respectively. These results demonstrated that plasma ranirestat exposure and the plasma protein binding of the drug were not substantially altered by normal, mild, or moderate hepatic impairment (protein binding 99.22%, 99.29%, and 99.00%, respectively). All adverse events were mild in severity. Based on these findings, no dose adjustment will be required for ranirestat in patients with mild or moderate hepatic impairment.

Medication safety in patients with hepatic impairment: A survey of community pharmacists' knowledge level and their practice in caring for these patients

Aims

To study community pharmacists' level of knowledge on medication safety in patients with hepatic impairment and their practice in caring for these patients.

Methods

Pharmacists from Dutch community pharmacies (n = 1545) were invited to participate in an online survey. The survey consisted of 27 questions covering 2 main topics: knowledge and current practice. The level of knowledge was measured by a 6‐item knowledge test. Multiple linear regression was used to identify predictors of correctly answered responses.

Results

In total, 338 pharmacists (22%) completed the questionnaire. The mean knowledge score was 2.8 (standard deviation 1.6). Only 30.3% of respondents were able to appropriately advise on use of analgesics in severe cirrhosis. Postgraduate education on hepatic impairment, knowledge of recently developed practical guidance, and fewer years of practice were associated with a higher level of knowledge. In total, 70.4% indicated to evaluate medication safety in a patient with hepatic impairment at least once weekly. In the past 6 months, 83.3% of respondents consulted a prescriber about a patient with hepatic impairment. Frequently encountered barriers in practice were insufficient knowledge on the topic and a lack of essential patient information (i.e. diagnosis and severity of the impairment).

Conclusion

Community pharmacists regularly evaluate the safety of medication in patients with hepatic impairment, yet their level of knowledge was insufficient and additional education is needed. Pharmacists experienced several difficulties in providing pharmaceutical care. If these issues are resolved, pharmacists can play a more active role in ensuring medication safety in their patients with hepatic impairment.

Evaluation of Information in Summaries of Product Characteristics (SmPCs) on the Use of a Medicine in Patients With Hepatic Impairment

Background: In 2005, the European Medicines Agency (EMA) released guidance on pharmacokinetic studies in patients with hepatic impairment. This guidance describes the design of these studies and what information should be presented in the Summary of Product Characteristics (SmPC). We aim to evaluate the availability and clinical applicability of information on medicine use in patients with hepatic impairment in SmPCs and registrational dossiers of recently approved medicines. Methods: We reviewed SmPC information on use in patients with hepatic impairment of 51 new medicines authorized between 2015 and 2017. Per medicine, we assessed the availability of nine information items derived from the EMA guidance, i.e. type of hepatic disease studied; stratification by severity of hepatic impairment; influence of hepatic impairment on the pharmacokinetics; safety advice in mild, moderate, and severe hepatic impairments; and dosing recommendation in mild, moderate, and severe hepatic impairments. If unavailable, the European Public Assessment Report (EPAR) and study report were consulted consecutively. Of available items, clinical applicability was assessed by labeling information as "clear" or "ambiguous". Results: Of 51 medicines, 15 had no pharmacokinetic study in patients with hepatic impairment described in their SmPC. The other 36 SmPCs contained on average seven of the nine information items (range 4-9). One SmPC contained all 9 items, and after consulting, the study reports, 11 SmPCs were complete. The item "type of hepatic disease studied" was available in one SmPC, though it could be retrieved in 21 study reports. Regarding clinical applicability, there was no medicine with all information items available and clearly formulated in the SmPC. A total of 12 medicines (33%) contained only clearly formulated information, while 24 (67%) contained at least one ambiguously formulated information item (range 0-4). Items often ambiguously formulated were: "definition of mild, moderate, and severe hepatic impairment" (15 ambiguous SmPCs) and "safety advice in severe hepatic impairment" (17 ambiguous SmPCs). Conclusion: While SmPCs contain a large part of information requested by the EMA, clinical applicability seems low, as it is often unclear to which specific type of hepatic disease patient the advice applies. This can negatively influence the practical use by healthcare professionals.

Role of enterohepatic recirculation in drug disposition: cooperation and complications

Enterohepatic recirculation (EHC) concerns many physiological processes and notably affects pharmacokinetic parameters such as plasma half-life and AUC as well as estimates of bioavailability of drugs. Also, EHC plays a detrimental role as the compounds/drugs are allowed to recycle. An in-depth comprehension of this phenomenon and its consequences on the pharmacological effects of affected drugs is important and decisive in the design and development of new candidate drugs. EHC of a compound/drug occurs by biliary excretion and intestinal reabsorption, sometimes with hepatic conjugation and intestinal deconjugation. EHC leads to prolonged elimination half-life of the drugs, altered pharmacokinetics and pharmacodynamics. Study of the EHC of any drug is complicated due to unavailability of the apposite model, sophisticated procedures and ethical concerns. Different in vitro and in vivo methods for studies in experimental animals and humans have been devised, each having its own merits and demerits. Involvement of the different transporters in biliary excretion, intra- and inter-species, pathological and biochemical variabilities obscure the study of the phenomenon. Modeling of drugs undergoing EHC has always been intricate and exigent models have been exploited to interpret the pharmacokinetic profiles of drugs witnessing multiple peaks due to EHC. Here, we critically appraise the mechanisms of bile formation, factors affecting biliary drug elimination, methods to estimate biliary excretion of drugs, EHC, multiple peak phenomenon and its modeling.