Exploring the Impact of Hepatic Impairment on Pralsetinib Pharmacokinetics

Pralsetinib is a kinase inhibitor indicated for the treatment of metastatic rearranged during transfection (RET) fusion-positive non-small cell lung cancer. Pralsetinib is primarily eliminated by the liver and hence hepatic impairment (HI) is likely alter its pharmacokinetics (PK). Mild HI has been shown to have minimal impact on the PK of pralsetinib. This hepatic impairment study aimed to determine the pralsetinib PK, safety and tolerability in subjects with moderate and severe HI, as defined by the Child-Pugh and National Cancer Institute Organ Dysfunction Working Group (NCI-ODWG) classification systems, in comparison to subjects with normal hepatic function. Based on the Child-Pugh classification, subjects with moderate and severe HI had similar systemic exposure (area under the plasma concentration time curve from time 0 to infinity [AUC0-∞]) to pralsetinib, with AUC0-∞ geometric mean ratios (GMR) of 1.12 and 0.858, respectively, compared to subjects with normal hepatic function. Results based on the NCI-ODWG classification criteria were comparable; the AUC0-∞ GMR were 1.22 and 0.858, respectively, for subjects with moderate and severe HI per NCI-ODWG versus those with normal hepatic function. These results suggested that moderate and severe hepatic impairment did not have a meaningful impact on the exposure to pralsetinib, thus not warranting a dose adjustment in this population.

Population Pharmacokinetics of Oral Azacitidine, and Exposure-Response Analysis in Acute Myeloid Leukemia

Oral azacitidine (oral-AZA) maintenance is approved for adults with acute myeloid leukemia (AML) in remission post-intensive chemotherapy, not proceeding to hematopoietic stem cell transplantation. This study aimed to develop a population pharmacokinetic (PopPK) model to characterize oral-AZA concentration-time profiles in patients with AML, myelodysplastic syndrome, or chronic myelomonocytic leukemia. PopPK-estimated exposure parameters were used to evaluate exposure-response relationships in the phase III QUAZAR AML-001 study. The PopPK dataset comprised 286 patients with 1,933 evaluable oral-AZA concentration records. The final PopPK model was a one-compartment model with first-order absorption incorporating an absorption lag time and first-order elimination. Regression analyses identified two oral-AZA exposure parameters (area under the plasma concentration-time curve at steady state (AUCss ); maximum plasma concentration (Cmax )) as statistically significant predictors for relapse-free survival (hazard ratio (HR) = 0.521, P < 0.001; HR = 0.630, P = 0.013; respectively), and AUCss as a significant predictor for overall survival (HR = 0.673, P = 0.042). The probability of grade ≥ 3 neutropenia was significantly increased with increases in AUCss (odds ratio (OR) = 5.71, 95% confidence interval (CI) = 2.73-12.62, P < 0.001), cumulative AUC through cycles 1 to 6 (OR = 2.71, 95% CI = 1.76-4.44, P < 0.001), and Cmax at steady-state (OR = 2.38, 95% CI = 1.23-4.76, P = 0.012). A decreasing trend was identified between AUCss and relapse-related schedule extensions, vs. an increasing trend between AUCss and event-related dose reductions. As the majority (56.8%) of patients required no dose modifications, and the proportions requiring schedule extension (19.4%) or dose reduction (22.9%) were almost equal, oral-AZA 300 mg once daily for 14 days is the optimal dosing schedule balancing survival benefit and safety risk.

Population Pharmacokinetics of Heptanoate in Healthy Subjects and Patients With Long-Chain Fatty Acid Oxidation Disorders Treated With Triheptanoin

Triheptanoin is an odd-carbon, medium-chain triglyceride consisting of three fatty acids with seven carbons each on a glycerol backbone, indicated for the treatment of adult and pediatric patients with long-chain fatty acid oxidation disorders (LC-FAOD). A total of 562 plasma concentrations of heptanoate, the most abundant and pharmacologically active metabolite of triheptanoin, from 13 healthy adult subjects and 30 adult and pediatric subjects with LC-FAOD were included in the population pharmacokinetic (PK) analyses. Multiple peaks of heptanoate observed in several subjects were characterized by dual first-order absorption with a lag time in the second absorption compartment. The disposition of heptanoate in human plasma was adequately described by one-compartmental distribution with a linear elimination. The apparent clearance (CL/F) and apparent volume of distribution were allometrically scaled with body weight to describe PK data across a wide range of age groups in subjects with LC-FAOD. The typical CL/F in adult subjects with LC-FAOD was ≈19% lower than that in healthy subjects. Model-estimated elimination half-life for LC-FAOD patients was ∼1.7 hours, supporting a recommended dosing frequency of ≥4 times per day. Covariate analyses indicate that age, race, and sex did not lead to clinically meaningful changes in the exposure of heptanoate.

Design and conduct considerations for studies in patients with hepatic impairment

Despite the liver being the primary site for clearance of xenobiotics utilizing a myriad of mechanisms ranging from cytochrome P450 enzyme pathways, glucuronidation, and biliary excretion, there is a dearth of information available as to how the severity of hepatic impairment (HI) can alter drug absorption and disposition (i.e., pharmacokinetics [PK]) as well as their efficacy and safety or pharmacodynamics (PD). In general, regulatory agencies recommend conducting PK studies in subjects with HI when hepatic metabolism/excretion accounts for more than 20% of drug elimination or if the drug has a narrow therapeutic range. In this tutorial, we provide an overview of the global regulatory landscape, clinical measures for hepatic function assessment, methods to stage HI severity, and consequently the impact on labeling. In addition, we provide an in-depth practical guidance for designing and conducting clinical trials for patients with HI and on the application of modeling and simulation strategies in lieu of dedicated trials for dosing recommendations in patients with HI.

Population pharmacokinetic analysis of tepotinib, an oral MET kinase inhibitor, including data from the VISION study

Purpose

Tepotinib is a highly selective, potent, mesenchymal–epithelial transition factor (MET) inhibitor, approved for the treatment of non-small cell lung cancer (NSCLC) harboring MET exon 14 skipping. Objectives of this population pharmacokinetic (PK) analysis were to evaluate the dose–exposure relationship of tepotinib and its major circulating metabolite, MSC2571109A, and to identify the intrinsic/extrinsic factors that are predictive of PK variability.

Methods

Data were included from 12 studies in patients with cancer and in healthy participants. A sequential modeling approach was used to analyze the parent and metabolite data, including covariate analyses. Potential associations between observed covariates and PK parameters were illustrated using bootstrap analysis-based forest plots.

Results

A two-compartment model with sequential zero- and first-order absorption, and a first-order elimination from the central compartment, best described the plasma PK of tepotinib in humans across the dose range of 30–1400 mg. The bioavailability of tepotinib was shown to be dose dependent, although bioavailability decreased primarily at doses above the therapeutic dose of 500 mg. The intrinsic factors of race, age, sex, body weight, mild/moderate hepatic impairment and mild/moderate renal impairment, along with the extrinsic factors of opioid analgesic and gefitinib intake, had no relevant effect on tepotinib PK. Tepotinib has a long effective half-life of ~ 32 h.

Conclusions

Tepotinib shows dose proportionality up to at least the therapeutic dose, and time-independent clearance with a profile appropriate for once-daily dosing. None of the covariates identified had a clinically meaningful effect on tepotinib exposure or required dose adjustments.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00280-022-04423-5.

Effect of Mild and Moderate Hepatic Impairment (defined by Child Pugh classification and National Cancer Institute-Organ Dysfunction Working Group criteria) on Pexidartinib Pharmacokinetics

Pexidartinib is a novel oral small‐molecule tyrosine kinase inhibitor targeting the colony‐stimulating factor 1 receptor. Pexidartinib undergoes extensive hepatic metabolism via multiple cytochrome P450 and uridine 5'‐diphospho‐glucuronosyl transferase enzymes, with ZAAD‐1006a as the only major metabolite in human plasma. As pexidartinib is extensively metabolized, hepatic impairment (HI) could lead to increased exposure to pexidartinib. The objective of the two phase 1, open‐label studies was to determine the pharmacokinetics of pexidartinib after a single 200‐mg dose in subjects with mild and moderate HI, based on Child–Pugh classification (PL3397‐A‐U123: 8 mild HI and 8 moderate HI vs 16 matched healthy controls) and National Cancer Institute Organ Dysfunction Working Group (NCI‐ODWG) criteria (PL3397‐A‐U129: 8 moderate HI versus 8 matched healthy controls [NCT04223635]). Based on Child–Pugh classification, exposure to pexidartinib (maximum observed concentration [C_max], area under the plasma concentration–time curve up to the last measurable concentration [AUC_last], and extrapolated to infinity [AUC_inf]) was similar in subjects with mild and moderate HI and in respective matched healthy controls, whereas ZAAD‐1006a exposure (AUC) was approximately 27% to 28% and 41% to 48% higher in mild and moderate HI, respectively. According to NCI‐ODWG criteria, total pexidartinib exposure was 42% to 46% higher in subjects with moderate HI, compared with healthy controls, and total ZAAD‐1006a exposure was 70% to 79% higher for subjects with moderate HI, compared with matched healthy controls with normal hepatic function. These findings were used to develop appropriate dose recommendations in patients with hepatic impairment.

Population Pharmacokinetic Analysis and Exploratory Exposure-Bleeding Rate Relationship of Emicizumab in Adult and Pediatric Persons with Hemophilia A

Background

Emicizumab is a bispecific monoclonal antibody developed for routine prophylaxis of bleeding in people with hemophilia A (PwHA). This work characterizes the pharmacokinetics of emicizumab in adult and pediatric PwHA, identifies factors contributing to its between-person variabilities, compares the pharmacokinetics following different dosing regimens, and makes a descriptive assessment of the exposure–bleeding events relationship.

Methods

A population pharmacokinetic model was developed, using a database of 389 PwHA from five clinical studies. Potential baseline covariate effects were assessed, including body size, age, race, presence of factor VIII inhibitors, and albumin levels. Using the population pharmacokinetic model, the estimated individual average exposures over the administration period were compared across categories of annualized bleeding rate.

Results

A linear one-compartment model with first-order absorption and elimination processes and no lag time best described the emicizumab pharmacokinetics. Body weight, albumin levels, age, and black race were statistically correlated with primary pharmacokinetic parameters, but only body weight had an important influence on exposure. Dosing regimens of 1.5 mg/kg weekly, 3 mg/kg every 2 weeks, or 6 mg/kg every 4 weeks provided similar average concentrations at steady state. A trend for lower exposure was observed in the small proportion of PwHA having an annualized bleeding rate > 4 (11.9%), suggesting that reducing exposure to lower levels may potentially increase the bleeding risk.

Conclusions

Emicizumab pharmacokinetics in PwHA was described with dose-independent parameters. Body weight was an important predictor of emicizumab pharmacokinetics. All three dosing regimens are predicted to achieve similar exposure associated with clinically meaningful prevention of bleeding.

Electronic supplementary material

The online version of this article (10.1007/s40262-020-00904-z) contains supplementary material, which is available to authorized users.

Pharmacokinetics of Ipatasertib in Subjects With Hepatic Impairment Using Two Methods of Classification of Hepatic Function

Ipatasertib is a highly selective small-molecule pan-Akt inhibitor in clinical development. Ipatasertib is predominantly eliminated by the liver, and therefore the effect of hepatic impairment on ipatasertib pharmacokinetics (PK) was evaluated. In this Phase I open-label, parallel group study, the PK of ipatasertib was evaluated in subjects with hepatic impairment based on both, the Child-Pugh and the National Cancer Institute-Organ Dysfunction Working Group (NCI-ODWG) classification for hepatic impairment. A single dose of ipatasertib at 100 mg was administered and the PK was characterized in healthy subjects with normal hepatic function or mild, moderate and severe hepatic impairment. Based on Child-Pugh classification, subjects with moderate or severe hepatic impairment had an approximately 2- and 3-fold increase in systemic exposure (AUC_0-∞ ) to ipatasertib, respectively, compared to subjects with normal hepatic function. Systemic exposure (AUC_0-∞ ) to ipatasertib in subjects with mild hepatic impairment was comparable to that in subjects with normal hepatic function. In accordance with reduced clearance capacity, subjects with mild to severe hepatic impairment showed lower systemic exposure (AUC_0-∞ ) of ipatasertib metabolite M1 (G-037720). Overall results were comparable between Child-Pugh and NCI-ODWG classification criteria. Based upon the results from this study, no dosage adjustment is required for ipatasertib when treating patients with mild hepatic impairment, whereas a dose reduction would be recommended for subjects with moderate or severe hepatic impairment. Based on real world data analysis, ∼2% of intended patient population is expected to need a modified dose due to moderate or severe hepatic impairment. This article is protected by copyright. All rights reserved.

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.

Pharmacokinetics and safety of niraparib in patients with moderate hepatic impairment

PURPOSE

The purpose of this study is to characterize niraparib pharmacokinetics (PK) and safety in patients with normal hepatic function (NHF) versus moderate hepatic impairment (MHI).

METHODS

Patients with advanced solid tumors were stratified by NHF or MHI (National Cancer Institute-Organ Dysfunction Working Group criteria [bilirubin > 1.5-3 × upper limit of normal and any aspartate aminotransferase elevation]). In the PK phase, all patients received one 300 mg dose of niraparib. In the extension phase, patients with MHI received niraparib 200 mg daily; patients with NHF received 200 or 300 mg based on weight (< 77 kg, ≥ 77 kg)/platelets (< 150,000/µL, ≥ 150,000/µL). PK parameters included maximum concentration (C_max), area under the curve to last measured concentration (AUC_last) and extrapolated to infinity (AUC_inf). Safety was assessed in both phases. Exposure-response (E-R) modeling was used to predict MHI effects on exposure and safety of niraparib doses ≤ 200 mg or 300/200 mg or 200/100 mg weight/platelet regimens.

RESULTS

In the PK phase (NHF, n = 9; MHI, n = 8), mean niraparib C_max was 7% lower in patients with MHI versus NHF. Mean exposure (AUC_last, AUC_inf) was increased by 45% and 56%, respectively, in patients with MHI without impacting tolerability. In the extension phase (NHF, n = 8; MHI, n = 7), the overall safety profile was consistent with previous trials. In patients with MHI, E-R modeling predicted niraparib 200 mg reduced Grade ≥ 3 thrombocytopenia incidence, whereas a 200/100 mg regimen yielded exposures below efficacy-associated levels in 15% of patients.

CONCLUSION

These findings support adjusting the 300 mg niraparib starting dose to 200 mg QD in patients with MHI.

TRIAL REGISTRATION

NCT03359850; registered December 2, 2017.

Population pharmacokinetics of belantamab mafodotin, a BCMA-targeting agent in patients with relapsed/refractory multiple myeloma

Belantamab mafodotin (belamaf) is an antibody-drug conjugate (ADC) targeting B-cell maturation antigen (BCMA). Nonlinear mixed-effects models were developed to characterize the population pharmacokinetics (PopPK) of ADC, total monoclonal antibody (mAb), and cysteine-maleimidocaproyl-MMAF (cys-mcMMAF) after 0.03-4.6 mg/kg dosing every 3 weeks in heavily pretreated patients with relapsed/refractory multiple myeloma (RRMM; DREAMM-1, n = 73; DREAMM-2, n = 218). Sequential modeling methodology was used. Individual post hoc parameter estimates from the final ADC model were used to develop total mAb and cys-mcMMAF models. Formal covariate selection used a modified stepwise forward inclusion method with backward elimination. A linear, two-compartment PopPK model with a time-varying clearance (CL) described ADC PK. Initial ADC typical value for CL for a DREAMM-2 patient was 0.936 L/day with a half-life of 11.5 days, over time CL was reduced by 28% resulting in a half-life of 14.3 days. Time to 50% maximal CL change was ~ 50 days. Baseline soluble BCMA (sBCMA), immunoglobulin (IgG), albumin, and bodyweight impacted ADC CL. Cys-mcMMAF concentrations were described with a linear two-compartment model linked to ADC; input rate was governed by deconjugation/intracellular proteolytic degradation of ADC represented by an exponentially decreasing MMAF:mAb (drug antibody ratio [DAR]) after each dose. Time to 50% DAR reduction was 10.3 days. Baseline sBCMA and IgG impacted cys-mcMMAF central volume of distribution. In conclusion, ADC, total mAb, and cys-mcMMAF concentration-time profiles in RRMM were well-described by PopPK models, and exposure was most strongly impacted by disease-related characteristics.

The impact of hepatic and renal function on panitumumab exposures in patients with metastatic RAS wild-type colorectal cancer

Purpose

Panitumumab is a human monoclonal antibody targeting the epidermal growth factor receptor for the treatment of wild-type RAS metastatic colorectal cancer (mCRC). Currently, no dedicated clinical studies have evaluated the effect of organ impairment on the pharmacokinetics of panitumumab. Here, we present data from late phase studies of panitumumab in patients with mCRC and analyses of the effect of hepatic or renal impairment on the exposure of panitumumab.

Methods

From three multicenter, open-label, phase 2 and phase 3 studies, 349 and 351 patients were included in hepatic and renal function subgroup analyses, respectively. Patients who received IV panitumumab and serum exposures were compared to patients with varying degrees of hepatic and renal organ dysfunction.

Results

The C_max and C_trough values for patients with mild (n = 119) and moderate (n = 4) hepatic impairment were within the range of serum concentrations of panitumumab for the normal hepatic function subgroup. The distributions of serum concentration of panitumumab in patients with mild (n = 85) or moderate (n = 19) renal impairment were similar to the serum concentrations of panitumumab in the normal renal function subgroup. Population pharmacokinetic modeling and covariate analysis results were also consistent with lack of any significant effect of renal or hepatic impairment on the pharmacokinetics of panitumumab. Additionally, real-world evidence from case studies of patients with mCRC and severe hepatic or renal impairment, which is a rare patient population to study, indicated lack of clinically relevant differences in exposure of panitumumab compared with patients with mCRC and normal hepatic or renal function.

Conclusions

Mild-to-moderate hepatic or renal dysfunction had no clinically meaningful impact on the pharmacokinetics of panitumumab in patients with mCRC. No dose adjustments for panitumumab are warranted in patients with mCRC with mild-to-moderate hepatic or renal dysfunction.

Trial registration

ClinicalTrials.gov; NCT00083616, NCT00089635, NCT00113763

Supplementary Information

The online version contains supplementary material available at 10.1007/s00280-021-04319-w.

Post-marketing surveillance study of trifluridine/tipiracil in patients with metastatic colorectal cancer

BACKGROUND

The novel oral nucleoside antineoplastic agent trifluridine/tipiracil was approved for metastatic colorectal cancer in Japan in March 2014. In this post-marketing surveillance study, we investigated the safety and efficacy of trifluridine/tipiracil in a real-world setting, particularly haematological drug reactions classified according to the baseline renal and hepatic functions.

METHODS

We investigated patients with metastatic colorectal cancer who received trifluridine/tipiracil during the first four treatment cycles prospectively. The patients typically received 35 mg/m2 trifluridine/tipiracil twice daily on days 1-5 and 8-12 every 28 days. The primary objective was to assess the safety of trifluridine/tipiracil, but its efficacy was also evaluated.

RESULTS

Between July 2014 and June 2016, 860 patients were enrolled in the study, and the safety and efficacy of trifluridine/tipiracil were evaluated in 823 patients. Adverse drug reactions occurred in 89.7% of the patients. The most common adverse drug reactions were decreased white blood cell count (67.0%) and neutrophil count (63.9%). Haematological drug reactions of grade ≥3 were observed in 41.7% of the patients with normal renal function; 50.3, 65.6 and 78.9% of the patients had mild, moderate and severe renal impairments, respectively. Hepatic impairment was not associated with a higher incidence of haematological drug reactions. The median overall survival was 8.4 months, with a 1-year survival rate of 33.7%.

CONCLUSION

This post-marketing surveillance study further confirmed the safety and tolerability profile of trifluridine/tipiracil observed in a clinical study setting.

Effect of Ponesimod Exposure on Total Lymphocyte Dynamics in Patients with Multiple Sclerosis

OBJECTIVE

The aim of this study was to characterize the relationship between ponesimod plasma concentrations and the temporal evolution of lymphocyte counts in multiple sclerosis (MS) patients.

METHODS

Population pharmacokinetic (PK) and PK/pharmacodynamic (PD) models were developed using data from phase I, II, and III trials, and the impact of clinically relevant covariates on PK and PD parameters was assessed. Simulations were conducted to evaluate the maximal lymphocyte count reduction after ponesimod treatment, and the time required for total lymphocyte counts to return to normal values after treatment interruption.

RESULTS

In MS patients, ponesimod PK were characterized by a low mean apparent plasma clearance (5.52 L/h) and a moderate mean apparent volume of distribution at steady state (239 L). The model developed indicated that none of the evaluated covariates (age, sex, formulation, food, body weight, clinical condition, and renal impairment) had a clinically relevant impact on the PK/PD parameters. In MS patients, total lymphocyte counts were characterized by a maximum reduction of 88.0% and a half maximal inhibitory concentration (IC₅₀) of 54.9 ng/mL. Simulations indicated that in patients with normal hepatic function treated with ponesimod 20 mg daily, total lymphocyte counts were reduced to 41% of baseline at trough. After stopping treatment, lymphocyte counts were restored to normal levels within one week.

CONCLUSIONS

The population PK/PD model well-characterized the PK of ponesimod and the time course of total lymphocyte counts in MS patients. Additionally, none of the evaluated covariates had a clinically relevant impact. This should be taken into consideration when assessing the risk of infection, administration of live-attenuated vaccines, and concomitant use of immunosuppressants.

Pharmacokinetics and Safety of Glasdegib in Participants With Moderate/Severe Hepatic Impairment: A Phase I, Single-Dose, Matched Case-Control Study

This phase I open-label trial (NCT03627754) assessed glasdegib pharmacokinetics and safety in otherwise healthy participants with moderate (Child-Pugh B) or severe (Child-Pugh C) hepatic impairment. Participants with hepatic impairment and age/weight-matched controls with normal hepatic function received a single oral 100-mg glasdegib dose under fasted conditions. The primary end points were area under the plasma concentration-time curve from time zero to infinity (AUC_inf ) and maximum plasma concentration (C_max ). Twenty-four participants (8/cohort) were enrolled. Glasdegib plasma exposures in moderate hepatic impairment were similar to controls, with adjusted geometric mean ratios (GMRs) of 110.8% (90% confidence interval [CI], 78.0-157.3) for AUC_inf and 94.8% (69.9-128.4) for C_max versus controls. In severe hepatic impairment, glasdegib plasma exposures were lower than controls (AUC_inf GMR, 75.7%; 90%CI, 51.5-111.0; C_max GMR, 58.0%; 90%CI, 37.8-89.0). Unbound glasdegib exposures were similar to controls for moderate (AUC_inf,u GMR, 118.1%; 90%CI, 88.7-157.2; C_max,u GMR, 101.1%; 90%CI, 78.4-130.3) and severe hepatic impairment (AUC_inf,u GMR, 116.3%; 90%CI 81.8-165.5; C_max,u GMR, 89.2%, 90%CI, 60.2-132.3). No treatment-related adverse events or clinically significant changes in laboratory values, vital signs, or electrocardiograms were observed. Together with previous findings, this suggests glasdegib dose modifications are not required based on hepatic impairment.

Discordance Between Child-Pugh and National Cancer Institute Classifications for Hepatic Dysfunction: Implications on Dosing Recommendations for Oncology Compounds

Guidance from the U.S. Food and Drug Administration (FDA) and the European Medicines Agency recommends using Child‐Pugh classification for pharmacokinetic evaluation in noncancer subjects with hepatic impairment (HI). Therefore, dosing recommendations for oncology compounds for patients with HI are commonly based on Child‐Pugh classification. In oncology clinical practice, National Cancer Institute classification (NCIc), is commonly used for evaluating hepatic function and dosing decisions for oncology patients. This work evaluated the discordance between the 2 systems and the impact on dosing recommendations. The classification system in HI studies was reviewed for FDA‐approved oncology compounds. Discordance between Child‐Pugh and NCIc was evaluated for sunitinib, dacomitinib, palbociclib, bosutinib, and axitinib. Pharmacokinetic (PK) analyses were conducted based on Child‐Pugh classification and NCIc. Review of 117 approved oncology compounds showed prevalent use of Child‐Pugh classification for dedicated HI studies in noncancer subjects. NCIc is commonly used in cancer patient studies. NCIc tended to classify subjects as less impaired versus Child‐Pugh (64.9%, 73.7%, and 61.5% of subjects with mild, moderate, and severe HI, respectively, via Child‐Pugh were classified as at least 1 category less impaired via NCIc). PK analyses by NCIc were consistent with Child‐Pugh for sunitinib, dacomitinib, and palbociclib. For bosutinib, NCIc showed less impact of HI than Child‐Pugh; an opposite trend was observed for axitinib. The impact of this considerable discordance between the 2 systems on dosing decisions bears consideration. When Child‐Pugh is used for HI study enrollment, exploratory PK analyses based on NCIc should be conducted. Prescribers should attempt to use the same classification system in the product label for dosing decisions.

Clinical pharmacokinetics and pharmacodynamics of ivosidenib in patients with advanced hematologic malignancies with an IDH1 mutation

PURPOSE

Isocitrate dehydrogenase (IDH) mutations lead to formation of the oncometabolite 2-hydroxyglutarate (2-HG), which is elevated in several solid and liquid tumors. Ivosidenib (AG-120) is a targeted, potent, oral inhibitor of the mutant IDH1 protein. We describe detailed pharmacokinetics and pharmacodynamics of ivosidenib in patients with advanced hematologic malignancies with an IDH1 mutation treated in a phase I study (ClinicalTrials.gov NCT02074839).

METHODS

Patients received single and multiple oral doses of ivosidenib from 100 mg twice daily to 1200 mg once daily (QD) in 28-day continuous cycles. Concentrations of ivosidenib and 2-HG in plasma, and 2-HG in bone marrow, were assessed at routine intervals. Plasma 4β-hydroxycholesterol/cholesterol ratios were assessed as a marker of CYP3A activity.

RESULTS

Ivosidenib was rapidly absorbed and slowly eliminated (half-life 72-138 h) after single and multiple dosing. Ivosidenib exhibited dose- and time-dependent pharmacokinetics, with exposure increasing sub-proportionally to dose, and clearance increasing with increasing dose. Plasma 2-HG concentrations were maximally and persistently inhibited in the majority of patients receiving 500-mg QD ivosidenib, to concentrations close to those observed in healthy subjects. Ivosidenib pharmacokinetics were not affected by mild or moderate renal impairment, mild hepatic impairment, age, weight, sex, race, or co-administration of weak CYP3A4 inhibitors or inducers. Moderate-to-strong CYP3A4 inhibitors decreased ivosidenib clearance. Ivosidenib also induced CYP3A enzyme activity, with increases in 4β-hydroxycholesterol/cholesterol ratios of 119-168% at 500-mg QD ivosidenib.

CONCLUSIONS

Ivosidenib 500-mg QD has favorable pharmacokinetic and pharmacodynamic profiles in patients with advanced hematologic malignancies with an IDH1 mutation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT02074839.

Population Pharmacokinetics of Glasdegib in Patients With Advanced Hematologic Malignancies and Solid Tumors

Glasdegib is an inhibitor of the Hedgehog pathway recently approved in the United States for the treatment of acute myeloid leukemia. A population pharmacokinetic analysis was conducted to characterize the kinetic behavior of glasdegib and its sources of variability (covariates) by utilizing data from 269 patients with cancer treated with oral glasdegib doses ranging from 5 to 640 mg/d. Nonlinear mixed-effects modeling was conducted using NONMEM (v.7.3) and Perl-speaks NONMEM (v.4.2.0). The estimated apparent total clearance, apparent central volume of distribution, and apparent peripheral volume of distribution were 6.27 L/h, 3.32 L, and 279.2 L, respectively. Age, sex, race, and hepatic function were not significant covariates on glasdegib pharmacokinetic parameters. Baseline body weight, percentage bone marrow blasts, creatinine clearance, and use of moderate or strong cytochrome P450 3A inhibitors were statistically significant covariates on apparent total clearance; however, the magnitude of the effects was not considered clinically meaningful.

FDA Approval Summary: Ruxolitinib for Treatment of Steroid-Refractory Acute Graft-Versus-Host Disease

On May 24, 2019, the Food and Drug Administration approved ruxolitinib for steroid-refractory acute graft-versus-host disease (SR-aGVHD) in adult and pediatric patients 12 years and older. Approval was based on Study INCB 18424-271 (REACH-1; NCT02953678), an open-label, single-arm, multicenter trial that included 49 patients with grades 2-4 SR-aGVHD occurring after allogeneic hematopoietic stem cell transplantation. Ruxolitinib was administered at 5 mg twice daily, with dose increases to 10 mg twice daily permitted after 3 days in the absence of toxicity. The Day-28 overall response rate was 57.1% (95% confidence interval [CI]: 42.2-71.2). The median duration of response was 0.5 months (95% CI: 0.3-2.7), and the median time from Day-28 response to either death or need for new therapy for acute GVHD was 5.7 months (95% CI: 2.2 to not estimable). Common adverse reactions included anemia, thrombocytopenia, neutropenia, infections, edema, bleeding, and elevated transaminases. Ruxolitinib is the first drug approved for treatment of SR-aGVHD. IMPLICATIONS FOR PRACTICE: Ruxolitinib is the first Food and Drug Administration-approved treatment for steroid-refractory acute graft-versus-host disease in adult and pediatric patients 12 years and older. Its approval provides a treatment option for the 60% of those patients who do not respond to steroid therapy.

Clinical pharmacokinetics and pharmacodynamics of ivosidenib, an oral, targeted inhibitor of mutant IDH1, in patients with advanced solid tumors

Background Mutant isocitrate dehydrogenase 1 and 2 (IDH1/IDH2) enzymes produce the oncometabolite D-2-hydroxyglutarate (2-HG). Ivosidenib (AG-120) is a targeted mutant IDH1 inhibitor under evaluation in a phase 1 dose escalation and expansion study of IDH1-mutant advanced solid tumors including cholangiocarcinoma, chondrosarcoma, and glioma. We explored the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of ivosidenib in these populations. Methods Ivosidenib was administered orally once (QD) or twice (BID) daily in continuous 28-day cycles; 168 patients received ≥1 dose within the range 100 mg BID to 1200 mg QD. PK and PD were assessed using validated liquid chromatography-tandem mass spectrometry assays. Results Ivosidenib demonstrated good oral exposure after single and multiple doses, was rapidly absorbed, and had a long terminal half-life (mean 40–102 h after single dose). Exposure increased less than dose proportionally. Steady state was reached by day 15, with moderate accumulation across all tumors (1.5- to 1.7-fold for area-under-the-curve at 500 mg QD). None of the intrinsic and extrinsic factors assessed affected ivosidenib exposure, including patient/disease characteristics and concomitant administration of weak CYP3A4 inhibitors/inducers. After multiple doses in patients with cholangiocarcinoma or chondrosarcoma, plasma 2-HG was reduced by up to 98%, to levels seen in healthy subjects. Exposure-response relationships for safety and efficacy outcomes were flat across the doses tested. Conclusions Ivosidenib demonstrated good oral exposure and a long half-life. Robust, persistent plasma 2-HG inhibition was observed in IDH1-mutant cholangiocarcinoma and chondrosarcoma. Ivosidenib 500 mg QD is an appropriate dose irrespective of various intrinsic and extrinsic factors. Trial RegistrationClinicalTrials.gov (NCT02073994).

A Pilot Study of Vinorelbine Safety and Pharmacokinetics in Patients with Varying Degrees of Liver Dysfunction

Vinorelbine tartrate is a semi‐synthetic vinca alkaloid and an inhibitor of microtubule polymerization with demonstrated antitumor properties across a spectrum of cancers. The pharmacokinetics of vinorelbine may be altered in individuals with liver dysfunction, considering that hepatic metabolism serves as the predominant route of drug elimination. This article reports the pharmacokinetics and safety of vinorelbine in patients with varying degrees of hepatic impairment, including dosing recommendations in this population.

Background.

Vinorelbine has demonstrated anticancer activity and is primarily metabolized in the liver. This single‐institution, phase I pilot study describes the safety and pharmacokinetics of vinorelbine in patients with varying degrees of hepatic impairment.

Materials and Methods.

Patients with treatment‐refractory solid tumors were enrolled into treatment arms based on vinorelbine dose (weekly infusions of 7.5–30 mg/m²) and liver function (normal liver function, mild, moderate, or severe liver dysfunction). Vinorelbine pharmacokinetics were evaluated to describe its relationship with liver function. Indocyanine green (ICG) clearance was assessed for correlation with pharmacokinetics.

Results.

Forty‐seven patients were enrolled, and a total of 108 grade 3–4 treatment‐related adverse events (AEs) occurred. Of these, grade 3–4 myelosuppression was the most common (34.3%). Thirty‐three (30.6%), 22 (20.4%), and 9 (8.3%) grade 3–4 AEs were observed in the vinorelbine 20 mg/m²/severe, 15 mg/m²/moderate, and 7.5 mg/m²/severe liver dysfunction groups, respectively, with the majority being nonhematologic toxicities. ICG clearance decreased as liver function worsened. Vinorelbine pharmacokinetics were not correlated with ICG elimination or the degree of liver dysfunction.

Conclusion.

For patients with severe liver dysfunction (bilirubin >3.0 mg/dL), vinorelbine doses ≥7.5 mg/m² are poorly tolerated. The high incidence of grade 3–4 AEs with 15 mg/m² vinorelbine in moderate liver dysfunction (bilirubin 1.5–3.0 mg/dL) raises concerns for its safety in this population. Vinorelbine pharmacokinetics are not affected by liver dysfunction; however, levels of the active metabolite 4‐O‐deacetylvinorelbine were not measured and may be higher in patients with liver dysfunction if its elimination is impacted by liver impairment to a greater degree than the parent drug.

Implications for Practice.

Vinorelbine remains widely prescribed in advanced malignancies and is under development in immunotherapy combinations. Given vinorelbine is primarily hepatically metabolized, understanding its safety and pharmacokinetics in liver dysfunction remains paramount. In this phase I pilot study, weekly vinorelbine at doses ≥7.5 mg/m² is poorly tolerated in those with severe liver dysfunction. Furthermore, a high incidence of grade 3–4 toxicities was observed with vinorelbine at 15 mg/m² in those with moderate liver dysfunction. Vinorelbine pharmacokinetics do not appear affected by degree of liver dysfunction. Further evaluation of levels of the free drug and active metabolites in relationship to liver function are warranted.

Risks and benefits of phase I liver dysfunction studies: should patients with severe liver dysfunction be included in these trials?

Introduction The goal of organ dysfunction Phase I trials is to characterize the safety and pharmacokinetics of novel agents in cancer patients with liver or kidney dysfunction, but the clinical benefit is not well established. Methods We reviewed 170 patients across 15 liver dysfunction studies at our institution, grouped based on the NCI-Organ Dysfunction Working Group criteria or Child-Pugh Score. Results The median survival for the entire cohort was two months and just one month amongst patients with severe liver dysfunction. Patients with normal or mild liver dysfunction, absence of tumor in liver, good performance status, higher serum albumin and lower bilirubin, aspartate transaminase and alkaline phosphatase had improved survival by univariate analysis. Serum albumin and liver function classification remained significant by multivariate analysis. Conclusion Given poor survival of patients with liver dysfunction, we need better criteria, such as albumin levels, for optimally selecting patients for liver dysfunction studies.

The Effect of Hepatic Impairment on Outcomes in Phase I Clinical Trials in Cancer Subjects

PURPOSE

The NCI Cancer Therapy Evaluation Program sponsors hepatic dysfunction phase I clinical trials (HDCT) and phase 1 clinical trials (P1CT) to determine safe doses and schedules of antineoplastic therapeutics. We sought to compare clinical outcomes between these trial types while stratifying by hepatotoxic agents.

EXPERIMENTAL DESIGN

Individual subject data were extracted from the records of 51 NCI-sponsored HDCT and P1CT. The NCI's Organ Dysfunction Working Group's hepatic impairment categorization and two drug-induced liver injury (DILI) scales (FDA R ratio and Hy's law) were used to classify subjects. The number of cycles administered and treatment discontinuation reason were also evaluated and compared between groups.

RESULTS

There were 513 and 1,328 subjects treated on HDCT (n = 9) and P1CT (n = 42), respectively. There were differing patterns of DILI with significant worsening of total bilirubin in subjects on HDCT, and worsening of alanine aminotransferase (ALT) in subjects on P1CT. Cholestatic peak patterns of liver impairment (predominant increases in alkaline phosphatase rather than transaminases) were more frequent in HDCT. Criteria for Hy's law were met by 11 subjects on P1CT, but not by any subjects on HDCT. Disease progression was the most common reason for treatment discontinuation, followed by adverse events at similar frequencies in both HDCT and P1CT.

CONCLUSIONS

The differential effects on hepatotoxicity suggest that underlying hepatic function may affect susceptibility to and patterns of DILI. The incorporation of additional measures of hepatic function may help identify those at highest risk of hepatotoxicity in future trials because baseline liver tests did not. Clin Cancer Res; 22(22); 5472-9. ©2016 AACR.

Phase 1 and pharmacokinetic study of intravenous irinotecan in refractory solid tumor patients with hepatic dysfunction

PURPOSE

To determine the recommended starting doses and pharmacokinetics of irinotecan in cancer patients with impaired liver function treated on a weekly schedule.

EXPERIMENTAL DESIGN

Patients with solid tumors who had impaired liver function were enrolled into four groups based on baseline serum total bilirubin and aspartate aminotransferase (AST)/alanine aminotransferase (ALT): Group 1 (n = 19): total bilirubin 1.5 to 3.0 x institutional upper limit of normal (IULN) and ALT/AST <or=5.0 x IULN; Group 2 (n = 7): total bilirubin 3.1 to 5.0 x IULN and ALT/AST <or=5.0 x IULN; Group 3 (n = 6): total bilirubin <or=1.5 x IULN and ALT/AST 5.1 to 20.0 x IULN; Group 4 (n = 10): total bilirubin 1.5 to 3.0 x IULN and ALT/AST 5.1 to 20.0 x IULN. Irinotecan was given as a 90-minute i.v. infusion weekly for the first 4 weeks in each 6-week cycle at starting doses which escalated from 40 to as much as 75 mg/m(2). After the first treatment, doses were adjusted based on individual patient toxicities. Starting doses for patients with hepatic dysfunction were derived from the maximum tolerated doses noted in the four hepatic dysfunction groups.

RESULTS

Forty-two patients were treated. Among the most frequent adverse events were neutropenia (41%, grades 3/4), diarrhea (15%, grades 3/4), nausea (10%, grade 3), and vomiting (5%, grades 3/4). Two patients died from drug-induced neutropenic sepsis. Two patients had objective tumor responses (complete response, liver metastases from unknown primary; partial response, colon cancer). Hepatic dysfunction reduced irinotecan clearance while increasing relative exposure to the active metabolite, 7-ethyl-10-hydroxycamptothecin (SN-38). SN-38 exposures in patients receiving doses of 40 to 75 mg/m(2) were comparable to exposures in patients with normal liver function treated with a starting dose of 125 mg/m(2).

CONCLUSIONS

Irinotecan starting doses that seem to be safe for hepatically impaired patients treated with the weekly schedule are 60, 50, 60, and 40 mg/m(2) for groups 1 to 4, respectively. At these starting doses, exposure to SN-38 and the adverse event profile are similar to that observed in patients with normal liver function and antitumor activity can be observed.