Exposure-response relationships for the efficacy and safety of filgotinib and its metabolite GS-829845 in subjects with rheumatoid arthritis based on phase 2 and phase 3 studies.

AIMS: Filgotinib is a potent, oral, JAK1-preferential inhibitor for the treatment of rheumatoid arthritis (RA). This report describes exposure-response (ER) analyses of filgotinib for dose confirmation based on three phase 3 and two phase 2 studies in moderate to severe RA patients. METHODS: The pharmacokinetic exposures used in ER analyses were derived from population pharmacokinetic analysis. The exposure-efficacy relationships were assessed for efficacy endpoints (ACR20/50/70 and DAS28) over effective area under curve (AUCeff ), the combined exposures of filgotinib and GS-829845 (major, active metabolite), with nonlinear logistic regression models developed. Also, a t-test was performed to compare the exposure between subjects who achieved response and those who did not. For the ER analyses of safety, exposures were examined between subjects who experienced and who did not experience the evaluated safety events, which was conducted separately for filgotinib and GS-829845. RESULTS: The nonlinear logistic regression showed increasing response with increasing exposure, with exposures at 200 mg dose primarily residing on the curve plateau. Also, AUCeff was significantly higher in the subjects who achieved responses compared to those who did not (10 900 vs 9900 h*ng/mL for ACR20, P value < .0001). For exposure-safety analyses, filgotinib and GS-829845 exposures were similar irrespective of the presence/absence of the evaluated safety endpoints, indicating no exposure-safety relationship for common treatment-emergent adverse events (TEAEs)/laboratory abnormalities and serious TEAEs/infections. CONCLUSIONS: ER analyses confirmed that filgotinib produced more robust therapeutic effects across the exposure range observed at 200 mg once daily compared to lower doses, and collectively with the lack of exposure-safety relationship, the 200 mg once daily dose was supported for commercialization.

Ceftazidime-Avibactam Population Pharmacokinetic Modeling and Pharmacodynamic Target Attainment Across Adult Indications and Patient Subgroups.

Ceftazidime-avibactam is a novel ß-lactam/ß-lactamase inhibitor combination for the treatment of serious infections caused by resistant gram-negative pathogens. Population pharmacokinetic (PopPK) models were built to incorporate pharmacokinetic (PK) data from five phase III trials in patients with complicated intra-abdominal infection (cIAI), complicated urinary tract infection (cUTI), or nosocomial (including ventilator-associated) pneumonia. Ceftazidime and avibactam pharmacokinetics were well-described by two-compartment disposition models, with creatinine clearance (CrCL) the key covariate determining clearance variability. Steady-state ceftazidime and avibactam exposure for most patient subgroups differed by ≤ 20% vs. healthy volunteers. Probability of PK/pharmacodynamic (PD) target attainment (free plasma ceftazidime > 8 mg/L and avibactam > 1 mg/L for ≥ 50% of dosing interval) was ≥ 94.9% in simulations for all patient subgroups, including indication and renal function categories. No exposure-microbiological response relationship was identified because target exposures were achieved in almost all patients. These modeling results support the approved ceftazidime-avibactam dosage regimens (2000-500 mg every 8 hours, adjusted for CrCL ≤ 50 mL/min).

Population pharmacokinetics and exposure-response of osimertinib in patients with non-small cell lung cancer.

AIMS: To develop a population (pop) pharmacokinetic (PK) model for osimertinib (AZD9291) and its metabolite (AZ5104) and investigate the exposure-response relationships for selected efficacy and safety parameters. METHODS: PK, safety and efficacy data were collected from two non-small cell lung cancer (NSCLC) patient studies (n = 748) and one healthy volunteer study (n = 32), after single or multiple once-daily dosing of 20-240 mg osimertinib. Nonlinear mixed effects modelling was used to characterise the popPK. Individual exposure values were used to investigate the relationship with response evaluation criteria in solid tumours (RECIST 1.1) efficacy parameters and key safety parameters (rash, diarrhoea, QTcF). RESULTS: A popPK model that adequately described osimertinib and its metabolite AZ5104 in a joint manner was developed. Body weight, serum albumin and ethnicity were identified as significant covariates on PK in the analysis, but were not found to have a clinically relevant impact on osimertinib exposure. No relationship was identified between exposure and efficacy over the dose range studied. A linear relationship was observed between exposure and the occurrence of rash or diarrhoea, and between concentration and QTcF, with a predicted mean (upper 90% confidence interval) increase of 14.2 (15.8) ms at the maximum concentration for an 80 mg once-daily dose at steady state. CONCLUSIONS: PopPK and exposure-response models were developed for osimertinib and AZ5104. There was no relationship between exposure and efficacy but a linear relationship between exposure and safety endpoints (rash, diarrhoea and QTcF) was observed.

Pharmacokinetics and safety of sirukumab following a single subcutaneous administration to healthy Japanese and Caucasian subjects.

OBJECTIVE: Sirukumab (CNTO 136) is a human mAb with high affinity and specificity for binding to interleukin-6. This Phase 1 study evaluated the pharmacokinetics, immunogenicity, safety, and tolerability of sirukumab following a single subcutaneous (s.c.) administration in healthy male Japanese and Caucasian subjects. METHODS: Japanese and Caucasian subjects were randomized to placebo or 25, 50, or 100 mg sirukumab. Blood samples were collected to measure serum sirukumab concentration and antibodies to sirukumab. Noncompartmental analysis and population pharmacokinetic modeling were conducted to characterize sirukumab pharmacokinetics. Adverse events were monitored at each visit. RESULTS: 25 Japanese and 24 Caucasian subjects received sirukumab and were included in the pharmacokinetic evaluation. Mean Cmax and AUC0-∞of sirukumab increased in an approximately dose-proportional manner in both Japanese and Caucasian subjects. Median tmax was 3 -5 days after s.c. administration of sirukumab. Mean t1/2 was 15 -16 days in Japanese and 15 -18 days in Caucasian subjects. A one-compartment population pharmacokinetic model adequately described sirukumab pharmacokinetics following s.c. administration. The estimated population means for CL/F, V/F, and Ka were 0.54 ±0.03 l/day, 12.2 ±0.55 l, and 0.77 ±0.07 day-1, respectively. Race was not a significant covariate on CL/F or V/F. No subject was positive for antibodies to sirukumab. Adverse events were generally mild and did not appear to be dose-related or lead to study discontinuation. CONCLUSIONS: Sirukumab pharmacokinetics following subcutaneous administration was linear at doses ranging 25 -100 mg and was comparable between Japanese and Caucasian subjects. A single subcutaneous administration of 25, 50, or 100 mg sirukumab appeared to be well tolerated by both Japanese and Caucasian healthy male subjects.

Pharmacokinetics, pharmacodynamics and safety of a human anti-IL-6 monoclonal antibody (sirukumab) in healthy subjects in a first-in-human study.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Interleukin (IL)-6 is a cytokine known for pleiotropic and pro-inflammatory functions. IL-6 is involved in various disease processes including lupus erythematosus, rheumatoid arthritis, insulin resistance and malignancy. Anti-IL-6 receptor therapy has recently been demonstrated to be effective in the treatment of patients with rheumatoid arthritis. WHAT THIS STUDY ADDS: Sirukumab, a human monoclonal antibody against soluble IL-6, has been found to bind to human IL-6 with high affinity and specificity and thus suppress the biological activity of IL-6. Preclinical studies have demonstrated the safety of sirukumab in cynomolgus monkeys, a toxicologically relevant animal species, following repeated intravenous and subcutaneous administrations. This study shows that sirukumab has desirable pharmacokinetic characteristics (linear pharmacokinetics with long half-life), a low incidence of immunogenicity and a well-tolerated safety profile in healthy subjects, supporting further development of sirukumab as a potentially valuable therapeutic agent. AIMS: To assess the safety, tolerability, pharmacokinetics (PK) and immunogenicity of sirukumab (CNTO 136) following intravenous (i.v.) infusion in healthy subjects. METHODS: Forty-five healthy adult subjects (38 men and seven women) were randomly assigned to receive a single i.v. dose of placebo or sirukumab (0.3, 1, 3, 6 or 10 mg kg(-1) in a dose-escalating manner). All treated subjects were observed for 96 h post infusion and underwent 20-week follow-up evaluations. Serum samples were collected to measure sirukumab concentrations, pharmacodynamic biomarkers and antibodies to sirukumab. Non-compartmental analysis and population PK modelling were conducted to characterize the PK of sirukumab. RESULTS: Adverse events were generally brief in duration, mild or moderate in intensity and non-dose-dependent. No serious adverse events were observed in the sirukumab-treated subjects. Both C(max) and AUC(0,∞) increased in an approximately dose-proportional manner. Median terminal half-life ranged from 18.5 to 29.6 days. A two-compartment model adequately described the PK of sirukumab following i.v. administration. Population estimates for the clearance (CL), the central volume of distribution (V(1)), the inter-compartmental clearance (Q) and the peripheral volume of distribution (V(2)) were 0.364 l day(-1), 3.28 l, 0.588 l day(-1) and 4.97 l, respectively. Compared with placebo subjects, a sustained decrease from baseline in C-reactive protein was observed in all sirukumab-treated dose groups, although no clear dose-response relationship was observed. No subjects were positive for antibodies to sirukumab. CONCLUSIONS: Sirukumab had a well-tolerated safety profile, desirable PK characteristics and a low incidence of immunogenicity following an i.v. infusion of 0.3 to 10 mg kg(-1) in healthy subjects.