Volenrelaxin (LY3540378) increases Renal Plasma Flow: A Randomized Phase 1 Trial

BACKGROUND AND HYPOTHESIS

Volenrelaxin, is a half-life-extended recombinant human relaxin protein developed for improving kidney perfusion and cardiorenal function. This study assessed the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of volenrelaxin following single- and multiple-ascending doses (SAD and MAD) administration.

METHODS

In this Phase 1, 4-part, randomized, double-blinded, placebo-controlled SAD and MAD study in healthy participants, SAD participants (n = 56) received an intravenous (IV) or subcutaneous (SC) dose of volenrelaxin or placebo in a dose-ascending manner. MAD participants (n = 77) received volenrelaxin or placebo SC once weekly for 5 weeks. Effective renal plasma flow (ERPF) and measured glomerular filtration rate (mGFR) were determined by para-aminohippurate and iohexol clearance, respectively.

RESULTS

Volenrelaxin demonstrated an extended half-life and increased acute and chronic placebo-adjusted ERPF change from baseline by 50% and 44%, respectively (p < 0.0001). Measured GFR was unchanged, while filtration fraction and afferent/efferent renal arteriolar resistances were reduced. Systolic and diastolic blood pressures decreased, and pulse rate increased with increasing volenrelaxin exposures, demonstrating maximal model-derived placebo-adjusted changes (90% confidence interval) of -6.16 (-8.04, -4.28) mmHg, -6.10 (-7.61, -4.58) mmHg, and + 4.39 (3.38, 5.39) bpm, respectively. Adverse events were mild, with no difference in orthostatic hypotension between volenrelaxin and placebo.

CONCLUSION

Volenrelaxin was well-tolerated, safe and suitable for weekly SC dosing. Volenrelaxin showed a sustained improvement in kidney perfusion upon repeated dosing, supporting further clinical development in chronic kidney disease and chronic heart failure. Clinical trial registration: NCT04768855.

Practical Applications of a Nausea and Vomiting Model in the Clinical Development of Additional Doses of Dulaglutide

Dulaglutide 3.0 and 4.5 mg weekly doses were approved for additional glycemic control in adult patients with type 2 diabetes inadequately controlled with metformin and 0.75 or 1.5 mg weekly doses of dulaglutide. Effects such as nausea and vomiting are commonly reported with dulaglutide and other glucagon-like peptide-1 receptor agonist therapies. Based on a pharmacokinetic/pharmacodynamic model-informed approach, a stepwise dose-escalation scheme with 4-week intervals between dose increments was suggested to mitigate gastrointestinal events for dulaglutide. These gastrointestinal events are dose dependent and attenuate over time with repeated dosing. A Markov chain Monte Carlo pharmacokinetic/pharmacodynamic joint model was developed using AWARD-11 data (N = 1842) to optimize dulaglutide dose escalation to 3.0 and 4.5 mg to mitigate gastrointestinal events. Model simulations evaluated probabilities of nausea and vomiting events for various dosing scenarios in patients needing higher doses for additional glycemic control. The model indicated that patients may dose escalate from 1.5 to 3.0 mg, then 4.5 mg weekly after at least 4 weeks on each dose. No clinically meaningful differences in nausea or vomiting events were expected when patients escalated to 3.0 or 4.5 mg following initiation at 0.75 or 1.5 mg dulaglutide. Based on the findings of this model, a minimum 4-week duration at each dose before escalation was appropriate to reduce gastrointestinal events of dulaglutide, consistent with observed gastrointestinal events data from the AWARD-11 study and supporting the currently recommended dose-escalation regimen of dulaglutide doses of 3.0 and 4.5 mg for additional glycemic control.

A model-based simulation of glycaemic control and body weight when switching from semaglutide to 3.0- and 4.5-mg doses of once-weekly dulaglutide

AIM

To evaluate HbA1c and body weight changes when semaglutide 0.5- or 1.0-mg once-weekly (QW) is switched to dulaglutide 3.0- or 4.5-mg QW via exposure-response modelling.

METHODS

HbA1c and body weight time-course models were developed and validated with data from the SUSTAIN 1 to 10 trials for semaglutide and the AWARD-11 trial for dulaglutide. Simulations were conducted for HbA1c and body weight over 52 weeks. In the initial 26 weeks, semaglutide was initiated at 0.25-mg and titrated to 0.5- or 1.0-mg QW via 4-weekly stepwise titration, followed by 26 weeks of dulaglutide initiated at 0.75- or 1.5-mg QW and escalated to 3.0- or 4.5-mg QW via 4-weekly stepwise titration.

RESULTS

At 26 weeks, model-predicted mean changes from baseline in HbA1c and weight for semaglutide 0.5 mg were up to -1.55% and -3.44 kg, respectively. After switching to dulaglutide 3.0 mg, further reductions were 0.19% and 1.40 kg, respectively, at 52 weeks. Predicted mean HbA1c and weight changes for semaglutide 1.0 mg at 26 weeks were -1.84% and -4.96 kg, respectively; after switching to dulaglutide 4.5 mg, HbA1c was maintained with additional weight reduction of up to 0.57 kg at 52 weeks. Glycaemic control was preserved when switching from semaglutide 1.0 mg to dulaglutide 3.0 mg.

CONCLUSION

Switching from semaglutide 0.5 mg to dulaglutide 3.0 or 4.5 mg with dose escalation potentially yields additional HbA1c and weight reductions; switching from semaglutide 1.0 mg to dulaglutide 4.5 mg may enhance weight loss.

Pharmacokinetics, Pharmacodynamics, and Safety of Dulaglutide After Single or Multiple Doses in Chinese Healthy Subjects and Patients with T2DM: A Randomized, Placebo-Controlled, Phase I Study

INTRODUCTION

This study evaluated the pharmacokinetics, pharmacodynamics, and safety of a single dulaglutide dose in Chinese healthy subjects and of multiple dulaglutide doses in Chinese patients with type 2 diabetes mellitus (T2DM).

METHODS

This two-part, double-blind, placebo-controlled study included 16 healthy subjects randomized to receive a single dose of placebo and two of three dulaglutide doses (0.5 mg, 0.75 mg, or 1.5 mg) in three treatment periods, and 42 patients with T2DM randomized to receive placebo or one of the three dulaglutide doses once weekly for 4 weeks. Pharmacokinetics and safety parameters were assessed in all participants, and pharmacodynamics effects were investigated in patients with T2DM.

RESULTS

Following a single-dose administration of 0.5 mg, 0.75 mg, or 1.5 mg dulaglutide in healthy subjects, geometric mean maximum concentrations (C_max) were 29.4, 44.2, and 81.5 ng/mL, respectively. Following weekly administration in patients with T2DM for 4 weeks, C_max were 26.3, 41.4, and 70.2 ng/mL, respectively, with accumulation ratios of 1.33-1.39. Geometric mean for half-life of 4-5 days and median time to C_max (t_max) of approximately 48 h were observed in both study populations. Dose-proportional increases in drug exposure were observed after both single and multiple dosing. Significant reductions in baseline-corrected fasting glucose and hemoglobin A1c (HbA1c) were observed in patients with T2DM who received dulaglutide 0.75 mg and 1.5 mg. Dulaglutide was well tolerated, with the majority of adverse events being gastrointestinal disorders of mild severity.

CONCLUSIONS

Pharmacokinetics, pharmacodynamics, and safety profiles of dulaglutide demonstrated in the present study support a once-weekly dosing regimen in Chinese patients with T2DM.

TRIAL REGISTRATION

NCT01667900 (ClinicalTrials.gov).

A Euglycemic Glucose Clamp Study to Evaluate the Bioavailability of LY2963016 Relative to Insulin Glargine in Healthy Chinese Subjects

Insulin glargine (IGlar) and LY2963016 (LY IGlar) are long-acting insulin analogs with identical primary amino acid sequences. We conducted a randomized, open-label, 2-treatment, 2-period, crossover study in healthy Chinese subjects to evaluate the relative bioavailability of LY IGlar to IGlar and pharmacokinetic (PK) and pharmacodynamic (PD) characteristics of LY IGlar. Subjects (n = 58) were randomized to receive single subcutaneous doses (0.5 U/kg) of LY IGlar and IGlar with a ≥7-day washout period between study treatments. Serum was collected before and up to 24 hours after dosing to assess PK characteristics. PD characteristics were assessed by euglycemic clamp up to 24 hours after dosing. Linear mixed-effects models were used to fit the log-transformed primary PK (maximum observed concentration and area under the concentration-time curve from time 0 to 24 hours) and PD parameters (maximum glucose infusion rate and total amount of glucose infused during clamp period). The geometric least squares means ratios (90% confidence interval) of LY IGlar to IGlar for maximum observed concentration and area under the concentration-time curve from time 0 to 24 hours were 0.961 (0.887-1.04) and 0.941 (0.872-1.01), respectively. The geometric least squares means ratios (90% confidence interval) of LY IGlar to IGlar were 0.91 (0.85-0.98) for maximum glucose infusion rate and 0.89 (0.82-0.97) for total amount of glucose infused during clamp period. LY IGlar demonstrated similarity to IGlar in PK and PD characteristics following single-dose (0.5 U/kg) administration in healthy Chinese subjects.

Physiologically-Based Pharmacokinetic Modeling of Atorvastatin Incorporating Delayed Gastric Emptying and Acid-to-Lactone Conversion

The drug-drug interaction profile of atorvastatin confirms that disposition is determined by cytochrome P450 (CYP) 3A4 and organic anion transporting polypeptides (OATPs). Drugs that affect gastric emptying, including dulaglutide, also affect atorvastatin pharmacokinetics (PK). Atorvastatin is a carboxylic acid that exists in equilibrium with a lactone form in vivo. The purpose of this work was to assess gastric acid-mediated lactone equilibration of atorvastatin and incorporate this into a physiologically-based PK (PBPK) model to describe atorvastatin acid, lactone, and their major metabolites. In vitro acid-to-lactone conversion was assessed in simulated gastric fluid and included in the model. The PBPK model was verified with in vivo data including CYP3A4 and OATP inhibition studies. Altering the gastric acid-lactone equilibrium reproduced the change in atorvastatin PK observed with dulaglutide. The model emphasizes the need to include gastric acid-lactone conversion and all major atorvastatin-related species for the prediction of atorvastatin PK.

Toward Better Understanding of Insulin Therapy by Translation of a PK-PD Model to Visualize Insulin and Glucose Action Profiles

Insulin replacement therapy is a fundamental treatment for glycemic control for managing diabetes. The engineering of insulin analogues has focused on providing formulations with action profiles that mimic as closely as possible the pattern of physiological insulin secretion that normally occurs in healthy individuals without diabetes. Hence, it may be helpful to practitioners to visualize insulin concentration profiles and associated glucose action profiles. Expanding on a previous analysis that established a pharmacokinetic (PK) model to describe typical profiles of insulin concentration over time following subcutaneous administration of various insulin formulations, the goal of the current analysis was to link the PK model to an integrated glucose‐insulin (IGI) systems pharmacology model. After the pharmacokinetic‐pharmacodynamic (PK‐PD) model was qualified by comparing model predictions with clinical observations, it was used to project insulin (PK) and glucose (PD) profiles of common insulin regimens and dosing scenarios. The application of the PK‐PD model to clinical scenarios was further explored by incorporating the impact of several hypothetical factors together, such as changing the timing or frequency of administration in a multiple‐dosing regimen over the course of a day, administration of more than 1 insulin formulation, or insulin dosing adjusted for carbohydrates in meals. Visualizations of insulin and glucose profiles for commonly prescribed regimens could be rapidly generated by implementing the linked subcutaneous insulin PK‐IGI model using the R statistical program (version 3.4.4) and a contemporary web‐based interface, which could enhance clinical education on glycemic control with insulin therapy.

Dose/Exposure-Response Modeling to Support Dosing Recommendation for Phase III Development of Baricitinib in Patients with Rheumatoid Arthritis

Baricitinib is an oral inhibitor of Janus kinases (JAKs), selective for JAK1 and 2. It demonstrated dose‐dependent efficacy in patients with moderate‐to‐severe rheumatoid arthritis (RA) in a phase IIb study up to 24 weeks. Population pharmacokinetic/pharmacodynamic (PopPK/PD) models were developed to characterize concentration‐time profiles and dose/exposure‐response (D/E‐R) relationships for the key efficacy (proportion of patients achieving American College of Rheumatology 20%, 50%, or 70% response rate) and safety endpoints (incidence of anemia) for the phase IIb study. The modeling suggested that 4 mg q.d. was likely to offer the optimum risk/benefit balance, whereas 2 mg q.d. had the potential for adequate efficacy. In addition, at the same total daily dose, a twice‐daily regimen is not expected to provide an advantage over q.d. dosing for the efficacy or safety endpoints. The model‐based simulations formed the rationale for key aspects of dosing, such as dose levels and dosing frequency for phase III development.

Modeling Pharmacokinetic Profiles of Insulin Regimens to Enhance Understanding of Subcutaneous Insulin Regimens

Insulin pharmacokinetics following subcutaneous administration were modeled, simulated, and displayed through an interactive and user‐friendly interface to illustrate the time course of administered insulins frequently prescribed, providing a simple tool for clinicians through a straightforward visualization of insulin regimens. Pharmacokinetic data of insulin formulations with different onset and duration of action from several clinical studies, including insulin glargine, regular insulin, neutral protamine Hagedorn (NPH), insulin lispro, and premixed preparations of NPH with regular insulin (Mix 70/30), and insulin lispro protamine suspension with insulin lispro (Mix 50/50, Mix 75/25), were used to develop a predictive population pharmacokinetic model of insulins with consideration of factors such as insulin formulation, weight‐based dosing, body‐weight effect on volume of distribution, and administration time relative to meals, on the insulin time‐action profile. The model‐predicted insulin profile of each insulin was validated and confirmed to be comparable to observed data via an external validation method. Model‐based simulations of clinically relevant insulin‐dosing scenarios to cater to specific initial patient and prescribing conditions were then implemented with differential equations using the R statistical program (version 3.2.2). The R package Shiny was subsequently applied to build a web browser interface to execute and visualize the model simulation outputs. The application of insulin pharmacokinetic modeling enabled informative visualization of insulin time‐action profiles and provided an efficient and intuitive educational tool to quickly convey and interactively explore many insulin time‐action profiles to ease the understanding of insulin formulations in clinical practice.

Pharmacokinetics, safety, and tolerability of single- and multiple-dose exenatide once weekly in Chinese patients with type 2 diabetes mellitus

BACKGROUND

This open-label, single-period study assessed the pharmacokinetics, safety, tolerability, and pharmacodynamics of exenatide once weekly (q.w.), following single and multiple weekly subcutaneous (s.c.) injections in native Chinese patients with type 2 diabetes (T2D).

METHODS

Patients (n = 25; mean [±SD] age 51.3 ± 8.2 years; body mass index 25.6 ± 2.4 kg/m(2) ; HbA1c 7.4 ± 1.2%; duration of diabetes 3.1 ± 3.1 years) previously treated with diet modification and exercise alone or incombination with stable metformin doses were enrolled in the study. Twenty-five patients received weekly doses of 2 mg, s.c., exenatide q.w. for 10 weeks, followed by 10 weeks observation. Pharmacokinetic parameters of exenatide, fasting plasma glucose (FPG), HbA1c, and body weight were summarized using descriptive statistics.

RESULTS

Steady state plasma exenatide concentrations (299 pg/mL) were attained within 8 weeks. Exenatide q.w. was generally well tolerated, and the majority of adverse events reported were mild in severity. The most frequent study drug-related adverse events were diarrhea and vomiting. Decreases were observed from baseline to 10 weeks in FPG (~3.0 mmol/L), HbA1c (~1.0%), and body weight (~3.8 kg).

CONCLUSIONS

This is the first clinical trial of exenatide q.w. in native Chinese patients with T2D. The results suggest that exenatide q.w. has a pharmacokinetic profile in this patient population similar to that observed in other ethnic and racial populations, and appears to be safe and generally well tolerated, with the potential to improve glycemic control and decrease body weight without increasing the risk of hypoglycemia.

Distribution of gemcitabine pathway genotypes in ethnic Asians and their association with outcome in non-small cell lung cancer patients

OBJECTIVE

Pharmacogenetics suggests variants of genes involved in gemcitabine pharmacology could be useful markers for predicting inter-ethnic and inter-patient outcomes from treatment with the agent. Here, we have characterized the distribution of variants of genes involved in gemcitabine pharmacology in ethnic Asian populations and their association with non-small cell lung cancer (NSCLC) patient outcome.

METHODS

All genes involved in gemcitabine transport, metabolism and activity were screened for suitable variants for analysis using publications and public databases. By pyrosequencing, the frequency of qualifying variants was characterized from germline DNA of 94 healthy Asian donors and 53 NSCLC patients receiving gemcitabine-based chemotherapy.

RESULTS

Significant differences in genotype distribution between Caucasians and Asians were seen at 10/25 (45%) variant loci. In NSCLC patients, CDA+435 C>T variants were associated with response (p=0.026) and time to progression (p=0.016) and SLC28A1+1561 G>A variants were associated with neutropenia (p=0.030) and thrombocytopenia nadir (p=0.037).

CONCLUSIONS

Many genotypes in gemcitabine pharmacology vary in their frequency between Caucasians and Asians. CDA+435, and SLC28A1+1561 are worthy of further investigation as potential indicators of patient outcome after gemcitabine treatment.

Pharmacogenetics of SLCO1B1 gene and the impact of *1b and *15 haplotypes on irinotecan disposition in Asian cancer patients

OBJECTIVE

To investigate the pharmacogenetic effect of SLCO1B1 *1a, *1b, *5 and *15 polymorphisms on irinotecan disposition in Asian cancer patients.

EXPERIMENTAL DESIGN

Irinotecan was administered over 90 min either at 100 mg/m on days 1, 8 and 15 with the regimen being repeated every 28 days (N=28) or at 375 mg/m once every three weeks (N=43). Plasma concentrations of irinotecan, 7-ethyl-10-hydroxycamptothecin and 7-ethyl-10-hydroxycamptothecinG were analysed after the first dose of the first cycle and the influence of SLCO1B1 *1a, *1b, *5 and *15 polymorphisms on the disposition of irinotecan and its metabolites were evaluated.

RESULTS

Pharmacokinetic parameters were obtained from 71 cancer patients. Genotypic-phenotypic correlates showed the clearance of irinotecan to be 3-fold lower in patients carrying the *15 haplotype than cancer patients with the reference genotype *1a/*1a (9.57+/-3.15 vs. 28.86+/-10.97 l/h/m; P=0.001). The area under the plasma concentration-time curve from zero to infinity and normalized by dose and body surface area (AUC0-nf/dose/BSA) were significantly higher in patients harbouring the *15 haplotype than patients with the reference genotype for irinotecan (39.27+/-15.17 vs. 17.32+/-6.30 h/m; P=0.003) and 7-ethyl-10-hydroxycamptothecin (1.28+/-0.53 vs. 0.69+/-0.32 h/m; P=0.021). The exposure levels to 7-ethyl-10-hydroxycamptothecinG also showed a statistically significant trend among the SLCO1B1 haplotype pairs, being approximately 10-fold lower in patients with *15 haplotype than with patients harbouring the reference genotype (3.57+/-1.95 vs. 12.0+/-6.09 h/m; P=0.016).

CONCLUSION

These findings suggest that (1) SLCO1B1 haplotypes may have a significant influence on the disposition of irinotecan and its metabolites in Asian cancer patients, and (2) patients with SLCO1B1*15 haplotype may be susceptible to increased sensitivity to irinotecan, which may manifest itself either by increased efficacy or toxicity or both owing to the increased exposure levels to 7-ethyl-10-hydroxycamptothecin.

A multicentre randomised phase II study of carboplatin in combination with gemcitabine at standard rate or fixed dose rate infusion in patients with advanced stage non-small-cell lung cancer

BACKGROUND

Intracellular gemcitabine triphosphate (dFdCTP) levels can be optimised by administering gemcitabine at a fixed dose rate infusion.

PATIENTS AND METHODS

Patients with chemonaive advanced non-small cell lung cancer (NSCLC) were randomised to receive gemcitabine at a fixed dose rate gemcitabine 750 mg/m(2) over 75 min (arm A) or gemcitabine 1000 mg/m(2) over 30 min (arm B) on days 1 and 8 every three week cycle. Carboplatin at AUC of 5 was administered in both treatment arms on day 1 of each cycle. End points were activity, tolerability and pharmacokinetics of plasma and intracellular gemcitabine.

RESULTS

76 patients were randomised. Response rate was 34% in arm A and 42% in arm B. Toxicity and quality of life scores were similar for both treatment arms. Mean plasma Cmax(gemcitabine) and mean dFdCTP AUC in arm A was 20.8 microM +/- 17.2 microM and 35,079 +/- 18,216 microM*min respectively and in arm B, 41.2 +/- 13.9 microM and 32 249 +/- 11 267 microM*min respectively. dFdCTP saturation was reached in Arm B but not in Arm A.

CONCLUSION

The saturability of dFdCTP accumulation in Arm A suggests optimal delivery of gemcitabine is achieved using fixed rate infusion compared to 30-min infusion. Fixed dose rate gemcitabine is active and feasible, supporting the concept of fixed dosing rate of gemcitabine in advanced NSCLC. However, this entails a longer infusion time with associated higher costs involved.

Population Pharmacokinetics of Tacrolimus in Whole Blood and Plasma in Asian Liver Transplant Patients

OBJECTIVES

The objectives of this study were to develop population pharmacokinetic models of tacrolimus in an Asian population with whole blood and plasma drug concentration data, to compare the variability of the pharmacokinetic parameters in these two matrices and to search for the main patient characteristics that explain the variability in pharmacokinetic parameters.

STUDY DESIGN

Prospective pharmacokinetic assessment followed by model fitting.

PATIENTS

Whole blood samples from 31 liver transplant patients in a local hospital receiving oral tacrolimus as part of their immunosuppressive therapy were assessed. Plasma samples from 29 of the 31 patients were also evaluated. Concentrations of tacrolimus in whole blood and plasma were determined by an electrospray high-performance liquid chromatography with tandem mass spectrometry. Two hundred and thirteen whole blood and 157 plasma tacrolimus concentrations were used for building two nonlinear mixed-effects population models to describe the disposition of tacrolimus in whole blood and plasma, respectively. Covariates that were investigated included demographic characteristics, biological markers of liver and renal functions, corticosteroid dose and haematological parameter.

RESULTS

A one-compartment model was used to describe the whole blood and plasma concentration-time data of tacrolimus after oral administration. For the whole blood population model, the population estimates of the first-order absorption rate constant (k(a)), apparent clearance based on whole blood concentration after oral administration (CL(B)/F) and apparent volume of distribution based on whole blood concentrations after oral administration (V(d,B)/F) were 2.08h(-1), 14.1 L/h and 217L, respectively. The coefficient of variations (CVs) of interpatient variabilities in CL(B)/F and V(d,B)/F were 65.7% and 63.8%, respectively. Bodyweight, liver and renal function influenced CL(B)/F, while height and haematocrit influenced V(d,B)/F. The residual (unexplained) variability was 34.8%. For the plasma population model, the population estimates of the k(a), apparent clearance based on plasma concentrations after oral administration (CL(P)/F) and apparent volume of distribution based on plasma concentrations after oral administration (V(d,P)/F) were 5.21h(-1), 537 L/h and 563L, respectively. The CVs of interpatient variabilities in CL(P)/F and V(d,P)/F were 96.0% and 105.4%, respectively. Bodyweight was found to influence CL(P)/F, while the erythrocyte-to-plasma concentration ratio influenced V(d,P)/F. The residual (unexplained) variability was 49.8% at the mean plasma concentration of 1.1 ng/mL.

CONCLUSIONS

Whole blood and plasma population pharmacokinetic models of tacrolimus in Asian adult and paediatric liver transplant patients were developed using prospective data in a clinical setting. This has identified and quantified sources of interindividual variability in CL(B)/F, V(d,B)/F, CL(P)/F and V(d,P)/F of tacrolimus in Asian liver transplant patients. Information derived from the whole blood population model may subsequently be used by clinicians for dosage individualisation through Bayesian forecasting.