Leveraging in vitro and pharmacokinetic models to support bench to bedside investigation of XTMAB-16 as a novel pulmonary sarcoidosis treatment.

Background: Sarcoidosis is a chronic, multisystem inflammatory disorder characterized by non-caseating epithelioid granulomas; infiltration of mononuclear cells; and destruction of microarchitecture in the skin, eye, heart, and central nervous system, and the lung in >90% of cases. XTMAB-16 is a chimeric anti-tumor necrosis factor alpha (TNFα) antibody, distinct from other anti-TNF antibodies based on its molecular structure. The efficacy of XTMAB-16 has not been clinically demonstrated, and it is still undergoing clinical development as a potential treatment for sarcoidosis. The current study demonstrates the activity of XTMAB-16 in a well-established in vitro sarcoidosis granuloma model, although XTMAB-16 is not yet approved by the United States Food and Drug Administration (FDA) for treatment of sarcoidosis, or any other disease. Objective: To provide data to guide safe and efficacious dose selection for the ongoing clinical development of XTMAB-16 as a potential treatment for sarcoidosis. Methods: First, XTMAB-16 activity was evaluated in an established in vitro model of granuloma formation using peripheral blood mononuclear cells from patients with active pulmonary sarcoidosis to determine a potentially efficacious dose range. Second, data obtained from the first-in-human study of XTMAB-16 (NCT04971395) were used to develop a population pharmacokinetic (PPK) model to characterize the pharmacokinetics (PK) of XTMAB-16. Model simulations were performed to evaluate the sources of PK variability and to predict interstitial lung exposure based on concentrations in the in vitro granuloma model. Results: XTMAB-16 dose levels of 2 and 4 mg/kg, once every 2 weeks (Q2W) or once every 4 weeks (Q4W) for up to 12 weeks, were supported by data from the non-clinical, in vitro secondary pharmacology; the Phase 1 clinical study; and the PPK model developed to guide dose level and frequency assumptions. XTMAB-16 inhibited granuloma formation and suppressed interleukin-1ß (IL-1ß) secretion in the in vitro granuloma model with a half maximal inhibitory concentration (IC50) of 5.2 and 3.5 µg/mL, respectively. Interstitial lung concentrations on average, following 2 or 4 mg/kg administered Q2W or Q4W, are anticipated to exceed the in vitro IC50 concentrations. Conclusion: The data presented in this report provide a rationale for dose selection and support the continued clinical development of XTMAB-16 for patients with pulmonary sarcoidosis.

Physiologically-based pharmacokinetic modelling to predict intragastric rifabutin concentrations in the treatment of Helicobacter pylori infection.

BACKGROUND: Sustained intragastric antibiotic exposure is important for Helicobacter pylori eradication, yet little is known about gastric pharmacology of commonly used H. pylori regimens. For rifabutin, differing intragastric concentrations based on dosing regimen may account for differences in reported eradication rates. AIM: To compare intragastric rifabutin concentrations between low-dose rifabutin (50 mg three time daily; as in RHB-105) and generically dosed rifabutin 150 mg once daily, 150 mg twice daily, and 300 mg once daily using a validated Physiologically-based pharmacokinetic (PBPK) model. METHODS: We obtained plasma pharmacokinetic data from the RHB-105 clinical development programs and used it to develop and validate a whole-body PBPK model using PK-SIM software. We modified the existing rifabutin model to include the impact of omeprazole on gastric pH and emptying time. Modelled intragastric rifabutin exposure was expressed as the time that each regimen maintained its concentration ≥MIC90 . RESULTS: Rifabutin 50 mg three times daily achieved significantly longer times with intragastric concentration above MIC90 (22.3 ± 1.1 h) than 150 mg once daily (8.3 ± 1.7 h), 150 mg twice daily (16.3 ± 2.3 h), or 300 mg once daily (8.5 ± 1.9 h) while providing the lowest mean maximal plasma concentration and mean area under the plasma concentration-time curve of all regimens studied. CONCLUSIONS: PBPK modelling showed rifabutin 50 mg three times daily had higher intragastric exposure times than 150 mg once daily or twice daily, or 300 mg once daily. This low-dose rifabutin regimen provides the highest potential for H. pylori eradication while minimising systemic rifabutin exposure.

Population Pharmacokinetics of Brigatinib in Healthy Volunteers and Patients With Cancer.

BACKGROUND AND OBJECTIVES: Brigatinib is an oral tyrosine kinase inhibitor approved in multiple countries for the treatment of patients with anaplastic lymphoma kinase-positive metastatic non-small cell lung cancer who have progressed on or are intolerant to crizotinib. We report a population pharmacokinetic model-based analysis for brigatinib. METHODS: Plasma concentration-time data were collected from 442 participants (105 healthy volunteers and 337 patients with cancer) who received single or multiple doses of oral brigatinib in one of five trials. Data were analyzed using non-linear mixed-effects modeling (NONMEM software version 7.3). RESULTS: Brigatinib plasma concentrations were best described by a three-compartment model with a transit compartment input (number of transit compartments = 2.35; mean transit time = 0.9 h). The final model included albumin as a covariate on apparent clearance. None of the additional covariates examined, including sex, age, race, body weight, mild or moderate renal impairment, total bilirubin, aspartate aminotransferase, and alanine aminotransferase, were found to meaningfully explain variability in apparent clearance, suggesting that no dose adjustment is required based on these covariates. CONCLUSIONS: Results from these population pharmacokinetic analyses informed the prescribing guidance for patients with mild or moderate renal impairment in the US Prescribing Information and the European Summary of Product Characteristics for brigatinib.

Brigatinib Dose Rationale in Anaplastic Lymphoma Kinase-Positive Non-Small Cell Lung Cancer: Exposure-Response Analyses of Pivotal ALTA Study.

Brigatinib is a kinase inhibitor indicated for patients with advanced anaplastic lymphoma kinase-positive non-small cell lung cancer who progressed on or are intolerant to crizotinib. Approval was based on results from a randomized, dose-ranging phase II study (ALK in Lung Cancer Trial of AP26113 (ALTA)). Despite an apparent dose-response relationship for efficacy in ALTA, an exposure-response relationship was not discernable using static models driven by time-averaged exposure. However, exposure-response modeling using daily time-varying area under the concentration curve as the predictor in time-to-event models predicted that increasing the dose of brigatinib (range, 30 mg once daily (q.d.) to 240 mg q.d.) would result in clinically meaningful improvements in progression-free survival (PFS), intracranial PFS, and overall survival. Grade ≥ 2 rash and amylase elevation were predicted to significantly increase with brigatinib exposure. These results provided support for a favorable benefit-risk profile with the approved dosing regimen (180 mg q.d. with 7-day lead-in at 90 mg) versus 90 mg q.d.

A Randomized Comparison of the Pharmacokinetics and Bioavailability of Fluticasone Propionate Delivered via Xhance Exhalation Delivery System Versus Flonase Nasal Spray and Flovent HFA Inhalational Aerosol.

PURPOSE: The exhalation delivery system with fluticasone propionate (Xhance®) has been shown to deliver drug substantially more broadly in the nasal cavity (particularly into superior/posterior regions), with less off-target loss of drug to drip-out and swallowing, than conventional nasal sprays. This open-label study evaluated the systemic bioavailability of Xhance® by comparing the pharmacokinetic (PK) properties of a single dose of fluticasone from 3 products administering the drug using 3 different devices: Xhance®, Flonase® (fluticasone propionate inhalational nasal spray), and Flovent® HFA (fluticasone propionate inhalational aerosol). METHODS: This open-label study was conducted in 2 parts. Study part 1 compared systemic exposure with a single dose of Xhance® 186 or 372 µg versus Flonase® 400 µg (3-way, 3-treatment, 3-sequence, randomized crossover in healthy subjects; n = 90). A separate study, part 2, under the same umbrella protocol, compared systemic exposure with Xhance® 372 µg versus Flovent® HFA 440 µg (2-way, 2-treatment, 2-sequence, randomized crossover in patients with mild to moderate asthma; n = 30). FINDINGS: With Xhance® 186 µg, the geometric least squares mean (LSM) Cmax was higher than with Flonase® 400 µg (16.02 vs 11.66 pg/mL, respectively; geometric mean ratio [GMR], 137.42%) and the geometric LSM AUC0-∞ values were similar (97.30 vs 99.61 pg · h/mL; GMR, 97.78%). With Xhance® 372 µg, the geometric LSM Cmax and AUC0-∞ were higher than with Flonase® 400 µg (Cmax, 23.50 vs 11.66 pg/mL [GMR, 201.53%]; AUC0-∞, 146.61 vs 99.61 pg · h/mL [GMR, 147.19%]). In part 2, the geometric LSM Cmax and AUC0-∞ values were lower with Xhance® 372 µg than with Flovent® HFA 440 µg (Cmax, 25.28 vs 40.02 pg/mL [GMR, 63.18%]; AUC0-∞, 205.78 vs 415.16 pg · h/mL [GMR, 49.57%]). IMPLICATIONS: Similar intranasal doses of Xhance® (372 µg) and Flonase® (400 µg) are clearly not bioequivalent. Systemic exposure is very low with all products. Systemic exposure is higher with Xhance® than with Flonase® and substantially lower than with Flovent® HFA 440 µg and, based on dose normalization, Flovent® HFA 220 µg. ClincalTrials.gov identifier: NCT02266927.

Pharmacokinetic Time Course Scaling of a Subcutaneously Administered Pegylated Peptide Conjugate for a First-in-Human Investigation.

BACKGROUND AND PURPOSE: Predicting absorption of macromolecules in humans following subcutaneous administration is complicated by interspecies differences in skin anatomy. The objective of this research was to test the hypothesis that an empiric relationship exists between non-human primates (NHPs) and humans in the absorption of a subcutaneously administered macromolecule which was then used to predict the time course of a pegylated peptide conjugate for planning of a first-in-human investigation. METHODS: Concentration data obtained from NHPs receiving intravenous and subcutaneous doses of a novel pegylated peptide conjugate were fit to a pharmacokinetic model. The model was then scaled to a virtual population of humans through incorporation of allometric scaling factors on clearance, volume and first-order rate absorption processes. Several scenarios of simulated data were compared with observed data obtained from a first-in-human investigation. RESULTS: NHP data were best described by a 2-compartment model with dual-parallel, first-order absorption processes, one of which exhibited a lag time. Empirically selected scaling factors, assuming an inverse relationship of body weight and absorption provided reasonable prediction of the peptide's time course in plasma. Employing fitted exponents based on observed human data improved the fit somewhat, however, did not correct entirely for over prediction observed with the empiric exponents. CONCLUSION: For macromolecules where the absorption can be described by first-order rate processes, an assumption of an inverse relationship in species size may predict the time course after subcutaneous administration and may support optimal study design for a first-in-human investigation.

Pharmacokinetics of cabozantinib tablet and capsule formulations in healthy adults.

Cabozantinib capsules (COMETRIQ) are approved for the treatment of patients with progressive metastatic medullary thyroid cancer. Cabozantinib tablets are investigational drug products considered to be potentially preferred pharmaceutical dosing forms. Two phase I open-label single-dose studies in healthy individuals were carried out to characterize the plasma pharmacokinetics of cabozantinib capsule and tablet formulations: a two-way crossover bioequivalence study (n=77) comparing the tablet formulation and the marketed capsule formulation at the approved 140 mg dose and a dose-proportionality study (n=21 per treatment arm) evaluating the 20, 40, and 60 mg tablet strengths. In the bioequivalence study, plasma exposure [area under the plasma concentration-time curve (AUC0-t and AUC0-inf)] values were similar (<10% difference) for both formulations and the 90% confidence intervals (CIs) around the ratio of geometric least-squares means (GLSM) were within the accepted bioequivalence limits of 80-125%. However, the GLSM for Cmax was 19% higher for the tablet formulation and the upper 90% CI for the ratio of GLSM (131.65%) was beyond the 80-125% range. Thus, the tablet and capsule formulations failed to fulfill the bioequivalence study acceptance criteria. In the dose-proportionality study, single doses of the 20, 40, and 60 mg cabozantinib tablet strengths showed dose-proportional increases where the 95% CIs for the slopes of the ln-transformed Cmax, AUC0-t, and AUC0-inf values versus ln-transformed cabozantinib dose included the value of 1. These findings indicate that cabozantinib plasma exposures increased proportionally with increasing cabozantinib dose over the 20-60 mg tablet strength dose range.

A PBPK workflow for first-in-human dose selection of a subcutaneously administered pegylated peptide.

Predicting the pharmacokinetic (PK) time course of a subcutaneously (SC) administered novel therapeutic protein using in silico approaches offers an opportunity to streamline the drug development process by facilitating selection of starting and target doses in initial human trials. Herein, we propose a workflow for predicting the human exposure time course following SC administration. Leveraging knowledge obtained following both intravenous and SC administration in monkeys, this workflow employs the development of a whole body physiologically-based pharmacokinetic (PBPK) model incorporating vascular circulation, lymphatic uptake and both renal and non-specific clearance mechanisms to predict the PK of a novel pegylated peptide. Optimization of the model was initially performed in monkeys, after which the model was scaled up to human proportion. Inclusion of a SC depot compartment allowed for precise simulation of the SC time course in monkeys. Simulated human exposure after SC administration was within approximately 20 % of the observed values and successfully predicted the time course of two subsequent dosing levels. This workflow represents one of the first publications of a PBPK workflow to predict the time course of a SC administered therapeutic protein based off of a single, non-human primate species and shows promise in facilitating the dose selection in first-in-human dose escalation studies for novel protein therapeutics.