Atezolizumab and Bevacizumab in Patients with Unresectable Hepatocellular Carcinoma: Pharmacokinetic and Safety Assessments Based on Hepatic Impairment Status and Geographic Region

Introduction: Phase 1b GO30140 and phase 3 IMbrave150 studies evaluated first-line atezolizumab + bevacizumab for unresectable hepatocellular carcinoma (HCC). Here, we evaluated pharmacokinetics (PK) and safety by hepatic impairment status and geographic region. Methods: Patients received atezolizumab 1,200 mg + bevacizumab 15 mg/kg IV every 3 weeks. Drug concentrations were evaluated by descriptive statistics and population PK. PK and adverse event frequencies were evaluated by hepatic impairment status and region. Results: 323 IMbrave150 patients and 162 GO30140 patients were PK evaluable. Compared with IMbrave150 patients who had normal hepatic function per the National Cancer Institute Organ Dysfunction Working Group (NCI-ODWG) criteria (n = 123), patients with mild impairment (n = 171) had a geometric mean ratio (GMR) of 0.92 for cycle 1 atezolizumab area under the concentration-time curve (AUC); patients with moderate impairment (n = 27) had a GMR of 0.88. Patients in Asia ([n = 162] vs. outside [n = 161]) had a GMR of 1.25 for cycle 1 atezolizumab AUC. Compared with GO30140 patients who had normal hepatic function (NCI-ODWG [n = 61]), patients with mild impairment (n = 92) had a GMR of 0.97 for cycle 1 peak bevacizumab concentrations; those with moderate impairment (n = 9) had a GMR of 0.94. Patients in Asia (n = 111) versus outside Asia (n = 51) had a GMR of 0.94 for cycle 1 peak bevacizumab concentration. PK results were generally comparable when evaluated based on additional hepatic functional definitions (Child-Pugh or albumin/bilirubin criteria) or study enrollment in Japan. No associations between atezolizumab PK and HCC etiology were seen. Adverse event frequencies were similar across evaluated groups. Conclusions: IMbrave150 and GO30140 patients with unresectable HCC had varying baseline hepatic impairment and high enrollment from Asia. PK data demonstrated considerable exposure overlap across groups. Treatment was tolerable across groups. No need for dose adjustment based on mild or moderate hepatic impairment or region is recommended based on this analysis

Population Pharmacokinetics and Exposure-Response Relationships of Astegolimab in Patients With Severe Asthma

Astegolimab is a fully human immunoglobulin G2 monoclonal antibody that binds to the ST2 receptor and blocks the interleukin-33 signaling. It was evaluated in patients with uncontrolled severe asthma in the phase 2b study (Zenyatta) at doses of 70, 210, and 490 mg subcutaneously every 4 weeks for 52 weeks. This work aimed to characterize astegolimab pharmacokinetics, identify influential covariates contributing to its interindividual variability, and make a descriptive assessment of the exposure-response relationships. A population pharmacokinetic model was developed using data from 368 patients in the Zenyatta study. Predicted average steady-state concentration was used in the subsequent exposure-response analyses, which evaluated efficacy (asthma exacerbation rate) and biomarker end points including forced expiratory volume in 1 second, fraction exhaled nitric oxide, blood eosinophils, and soluble ST2. A 2-compartment disposition model with first-order elimination and first-order absorption best described the astegolimab pharmacokinetics. The relative bioavailability for the 70-mg dose was 15.3% lower. Baseline body weight, estimated glomerular filtration rate, and eosinophils were statistically correlated with pharmacokinetic parameters, but only body weight had a clinically meaningful influence on the steady-state exposure (ratios exceeding 0.8-1.25). The exposure-response of efficacy and biomarkers were generally flat with a weak trend in favor of the highest dose/exposure. This study characterized astegolimab pharmacokinetics in patients with asthma and showed typical pharmacokinetic behavior as a monoclonal antibody-based drug. The exposure-response analyses suggested the highest dose tested in the Zenyatta study (490 mg every 4 weeks) performed close to the maximum effect, and no additional response may be expected above it

Pharmacokinetics and Exposure-Response Analysis of Venetoclax plus Obinutuzumab in Chronic Lymphocytic Leukemia: Phase 1b Study and Phase 3 CLL14 Trial

Introduction This study aims to investigate pharmacokinetics (PK) and exposure-response parameters of the 400 mg once-daily venetoclax dose regimen in combination with obinutuzumab, which was approved for the first-line (1L) treatment of chronic lymphocytic leukemia (CLL) based on data from the phase 3 CLL14 study and the phase 1b dose-finding GP28331 study. Methods Parameter estimates and uncertainty, which were estimated by a previously developed population PK (popPK) model, were used as informative priors for this analysis. They were re-estimated, and then used to evaluate additional covariate effects, describe venetoclax PK when administered with obinutuzumab, and provide empirical Bayes estimates of PK parameters and exposure. Exposure-progression-free survival (PFS) and exposure-safety relationships were assessed using data from CLL14, with steady-state nominal venetoclax exposure (C-meanSS,C-nominal) as the predictor variable. Exposure-safety analyses were conducted using logistic regression for selected treatment-emergent grade >= 3 adverse events (AEs) and serious AEs (SAEs). Dose intensities were summarized by tertiles of C-meanSS,C-nominal. Results PK data from 274 patients (CLL14, n = 194; GP28331, n = 80) were included. The final model provided good fit of the observed data. Obinutuzumab co-administration, history of prior treatments, and disease severity at baseline had no appreciable influence on venetoclax steady-state exposure. No significant correlations were observed between venetoclax exposure and PFS, or between venetoclax exposure and the probability of treatment-emergent grade >= 3 neutropenia, grade >= 3 thrombocytopenia, grade >= 3 infections, and SAEs. Median dose intensities for venetoclax and obinutuzumab remained similar across venetoclax exposure tertiles. Conclusion PopPK and exposure-efficacy, exposure-safety, and exposure-tolerability analyses support the 400 mg once-daily venetoclax dose plus obinutuzumab for 1L treatment in patients with CLL

Population repeated time-to-event analysis of exacerbations in asthma patients : A novel approach for predicting asthma exacerbations based on biomarkers, spirometry, and diaries/questionnaires

Identification of covariates, including biomarkers, spirometry, and diaries/questionnaires, that predict asthma exacerbations would allow better clinical predictions, shorter phase II trials and inform decisions on phase III design, and/or initiation (go/no-go). The objective of this work was to characterize asthma-exacerbation hazard as a function of baseline and time-varying covariates. A repeated time-to-event (RTTE) model for exacerbations was developed using data from a 52-week phase IIb trial, including 502 patients with asthma randomized to placebo or 70 mg, 210 mg, or 490 mg astegolimab every 4 weeks. Covariate analysis was performed for 20 baseline covariates using the full random effects modeling approach, followed by time-varying covariate analysis of nine covariates using the stepwise covariate model (SCM) building procedure. Following the SCM, an astegolimab treatment effect was explored. Diary-based symptom score (difference in objective function value [dOFV] of -83.7) and rescue medication use (dOFV = -33.5), and forced expiratory volume in 1 s (dOFV = -14.9) were identified as significant time-varying covariates. Of note, time-varying covariates become more useful with more frequent measurements, which should favor the daily diary scores over others. The most influential baseline covariates were exacerbation history and diary-based symptom score (i.e., symptom score was important as both time-varying and baseline covariate). A (nonsignificant) astegolimab treatment effect was included in the final model because the limited data set did not allow concluding the remaining effect size as irrelevant. Without time-varying covariates, the treatment effect was statistically significant (p < 0.01). This work demonstrated the utility of a population RTTE approach to characterize exacerbation hazard in patients with severe asthma