Population pharmacokinetic modeling for intravenous temsirolimus and sirolimus metabolite in subjects with various solid tumors

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 2522-2522
Author(s):  
D. Sonnichsen ◽  
S. Liao ◽  
A. Berkenblit ◽  
J. Boni
Keyword(s):  
Objective Response ◽  
Progression Free Survival ◽  
Compartment Model ◽  
Population Pharmacokinetic ◽  
Nonlinear Mixed Effects Models ◽  
Blood Concentrations ◽  
Population Pharmacokinetic Modeling ◽  
Apparent Clearance ◽  
Exposure Profile ◽  
Clinical Responses

2522 Background: Temsirolimus (TEMSR) is an mTOR inhibitor approved for treatment of patients with advanced renal cell carcinoma, and under development for relapsed/refractory mantle cell lymphoma (MCL). In MCL, TEMSR showed a dose-related increase in median progression-free survival [4.8 vs. 3.4 mo] and objective response rate [22% vs 6%] for 175 mg x 3 wks then 75 or 25 mg weekly regimens (175/75-mg and 175/25-mg), respectively. We aim to characterize the population pharmacokinetic exposure, covariate influence, and differences afforded by these regimens. Methods: Nonlinear mixed-effects models of TEMSR and sirolimus (SIR; major active metabolite) blood concentrations were defined in healthy subjects and patients. Modeling for TEMSR employed a 4-compartment model with saturable distribution to red cells and peripheral tissue, and modeling for SIR utilized a linear 2- compartment model with factor for dose. Covariates included demographic factors, clinical labs, and disease condition. Following validation, simulations with variability were used to evaluate effects of covariates on exposure. Results: Final datasets comprised 1342 observations from 150 subjects (TEMSR) and 1648 observations from 279 subjects (SIR). In a typical patient (56-year-old male weighing 76.5 kg), disease affected TEMSR clearance (62.4 L/h in MCL, 92.1 L/h in breast cancer vs. 112 L/h for other subjects). Dose, single vs. multiple, and body weight affected SIR apparent clearance. Simulations for the 175/75-mg regimen indicate that significant covariates yield only modest differences on blood exposures. For MCL (175/75-mg regimen), TEMSR Cmax (week 3) was 2574 ng/mL and SIR Ctrough (week 6) was 10.7 ng/mL. AUC for the 75-mg maintenance arm was ∼2.3-fold (TEMSR) and ∼3.5-fold higher (SIR) than respective values of the 25-mg arm. Correlation of average AUC to clinical response was not apparent. Conclusions: No significant differential effects were observed for age, gender, race, or hepatic and renal laboratory measures. Covariates of disease, while significant, have only modest effects on the exposure profile. Higher clinical responses observed with the 175/75-mg regimen as compared with the 175/25-mg regimen may critically derive from differences in exposure. [Table: see text]

Cabozantinib (C) exposure-response (ER) analysis for the phase 3 CheckMate 9ER (CM 9ER) trial of nivolumab plus cabozantinib (N+C) versus sunitinib (S) in first-line advanced renal cell carcinoma (1L aRCC).

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 4561-4561
Author(s):  
Amishi Yogesh Shah ◽  
Robert J. Motzer ◽  
Andrea B. Apolo ◽  
Thomas Powles ◽  
Bernard Escudier ◽  
...  
Keyword(s):  
Objective Response ◽  
Progression Free Survival ◽  
Average Concentration ◽  
Population Pharmacokinetic ◽  
Phase 3 ◽  
Population Pharmacokinetic Modeling ◽  
Dose Modification ◽  
Apparent Clearance ◽  
Dose Modifications ◽  
The Impact

4561 Background: In the phase 3 CM 9ER trial (NCT03141177), N+C significantly improved progression-free survival (PFS; HR 0.51, 95% CI 0.41–0.64; p < 0.0001), overall survival (OS; HR 0.60, 98.89% CI 0.40–0.89; p = 0.0010), and objective response rate (p < 0.0001) vs S in 1L aRCC (Choueiri, 2020). N+C was generally well tolerated with low rates of treatment-related discontinuations, indicating successful adverse event (AE) management with dose modification to maintain tolerability. Here the impact of C exposure on efficacy and safety outcomes in CM 9ER was evaluated using ER analysis. Methods: Patients (pts, N = 320) with previously untreated aRCC received C 40 mg QD in combination with N 240 mg Q2W; dose reductions of C to 20 mg QD or 20 mg Q2D were allowed to manage AEs. Time-to-event Cox proportional hazard ER models were developed to characterize the relationship between predicted C exposure or apparent clearance (CL/F) and specified endpoints, including PFS, dose modification, and select AEs (palmar-plantar erythrodysesthesia [PPE; Gr ≥1], diarrhea [Gr ≥3], hypertension [Gr ≥3], fatigue/asthenia [Gr ≥3], and ALT/AST elevation [Gr ≥3]). C exposure was defined as the overall average concentration from time zero to the time of event or censoring (CAVG) and estimated by population pharmacokinetic modeling for a typical patient. ER analysis for OS was not done due to the low number of events at the database lock date (March 30, 2020). Results: In the ER analysis of PFS, predicted C exposure at 40-mg and 20-mg QD doses was not significantly associated with the rate of progression or death (HR 1.00, 95% CI 0.78–1.27, for 20-mg vs 40-mg dose). In the ER analysis of AEs, lower predicted C exposure was significantly associated with lower rates of PPE (HR 0.63, 95% CI 0.50–0.78, for 20-mg vs 40-mg dose) and diarrhea (HR 0.48, 95% CI 0.29–0.80) but was not significantly associated with the rates of hypertension, fatigue/asthenia, or ALT/AST elevation. Higher predicted C CL/F was associated with a lower rate of C dose modification; however, this association was not statistically significant (HR 0.80, 95% CI 0.57–1.12, for CL/F 3.2 vs 1.2 L/hr). Conclusions: In ER models of pts with 1L aRCC treated with the combination of N+C, C exposure was not significantly associated with PFS; however, higher C exposure was associated with higher rates of PPE and diarrhea. ER modeling predicts that a starting dose of 40 mg QD C in combination with N with appropriate dose modifications to manage C AEs will not adversely affect the efficacy of the combination in 1L aRCC. Clinical trial information: NCT03141177.

scholarly journals Evaluation of the Adequacy of WHO Revised Dosages of the First-Line Antituberculosis Drugs in Children with Tuberculosis Using Population Pharmacokinetic Modeling and Simulations

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
Yasuhiro Horita ◽  
Abdullah Alsultan ◽  
Awewura Kwara ◽  
Sampson Antwi ◽  
Antony Enimil ◽  
...  
Keyword(s):  
Compartment Model ◽  
World Health ◽  
Population Pharmacokinetic ◽  
Optimal Dosage ◽  
Nonlinear Mixed Effects Models ◽  
First Line ◽  
Time Curve ◽  
Drug Concentrations ◽  
Target Values ◽  
Population Pk

ABSTRACTOptimal doses for antituberculosis (anti-TB) drugs in children have yet to be established. In 2010, the World Health Organization (WHO) recommended revised dosages of the first-line anti-TB drugs for children. Pharmacokinetic (PK) studies that investigated the adequacy of the WHO revised dosages to date have yielded conflicting results. We performed population PK modeling using data from one of these studies to identify optimal dosage ranges. Ghanaian children with tuberculosis on recommended therapy with rifampin (RIF), isoniazid (INH), pyrazinamide (PZA), and ethambutol (EMB) for at least 4 weeks had blood samples collected predose and at 1, 2, 4, and 8 hours postdose. Drug concentrations were determined by validated liquid chromatography-mass spectrometry methods. Nonlinear mixed-effects models were applied to describe the population PK of those drugs using MonolixSuite2016R1 (Lixoft, France). Bayesian estimation was performed, the correlation coefficient, bias, and precision between the observed and predicted areas under the concentration-time curve (AUCs) were calculated, and Bland-Altman plots were analyzed. The population PK of RIF and PZA was described by a one-compartment model and that for INH and EMB by a two-compartment model. Plasma maximum concentration (Cmax) and AUC targets were based on published results for children from India. The lowest target values for pediatric TB patients were attainable at the WHO-recommended dosage schedule for RIF and INH, except forN-acetyltransferase 2 non-slow acetylators (rapid and intermediate acetylators) in the lower-weight bands. However, higher published adult targets were not attainable for RIF and INH. The targets were not achieved for PZA and EMB. (This study has been registered at ClinicalTrials.gov under identifier NCT01687504.)

Population pharmacokinetic modeling and dosing simulations of tobramycin in pediatric patients with cystic fibrosis

2021 ◽  
Author(s):  
Antonin Praet ◽  
Laurent Bourguignon ◽  
Florence Vetele ◽  
Valentine Breant ◽  
Charlotte Genestet ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Dose Adjustment ◽  
Total Body Weight ◽  
Compartment Model ◽  
Therapeutic Drug ◽  
Population Pharmacokinetic ◽  
Time Curve ◽  
Population Pharmacokinetic Modeling ◽  
Two Compartment Model ◽  
Total Body

Initial dosing and dose adjustment of intravenous tobramycin in cystic fibrosis children is challenging. The objectives of this study were to develop nonparametric population pharmacokinetic (PK) models of tobramycin in children with CF to be used for dosage design and model-guided therapeutic drug monitoring. We performed a retrospective analysis of tobramycin PK data in our CF children center. The Pmetrics package was used for nonparametric population PK analysis and dosing simulations. Both the maximal concentration over the MIC (Cmax/MIC) and daily area under the concentration-time curve to the MIC (AUC 24 /MIC) ratios were considered as efficacy target. Trough concentration (Cmin) was considered as the safety target. A total of 2884 tobramycin concentrations collected in 195 patients over 9 years were analyzed. A two-compartment model including total body weight, body surface area and creatinine clearance as covariates best described the data. A simpler model was also derived for implementation into the BestDose software to perform Bayesian dose adjustment. Both models were externally validated. PK/PD simulations with the final model suggest that an initial dose of tobramycin of 15 to 17.5 mg/kg/day was necessary to achieve Cmax/MIC ≥ 10 values for MIC values up to 2 mg/L in most patients. The AUC 24 /MIC target was associated with larger dosage requirements and higher Cmin. A daily dose of 12.5 mg/kg would optimize both efficacy and safety target attainment. We recommend to perform tobramycin TDM, model-based dose adjustment, and MIC determination to individualize intravenous tobramycin therapy in children with CF.

scholarly journals Use of Pharmacokinetic and Pharmacodynamic Principles To Determine Optimal Administration of Daptomycin in Patients Receiving Standardized Thrice-Weekly Hemodialysis

2011 ◽  
Vol 55 (4) ◽  
pp. 1677-1683 ◽  
Author(s):  
Nimish Patel ◽  
Katie Cardone ◽  
Darren W. Grabe ◽  
Shari Meola ◽  
Christopher Hoy ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Monte Carlo ◽  
Body Weight ◽  
Infective Endocarditis ◽  
Population Model ◽  
Area Under The Curve ◽  
Compartment Model ◽  
Population Pharmacokinetic ◽  
Exposure Profile ◽  
Trough Concentrations

ABSTRACTThis study identified optimal daptomycin dosing for patients receiving thrice-weekly hemodialysis (HD). Twelve adult patients on HD received daptomycin at 6 mg/kg of body weight intravenously (i.v.) one time; plasma and dialysate samples were collected over 3 days. A 2-compartment model with separate HD and non-HD clearance terms was fit to the data. A series of 9,999-subject Monte Carlo simulations (MCS) was performed to identify HD dosing schemes providing efficacy and toxicity profiles comparable to those obtained for MCS employing the daptomycin population pharmacokinetic (PK) model derived from patients in theStaphylococcus aureusbacteremia-infective endocarditis (SAB-IE) study. For efficacy, we selected the HD dosing scheme which generated an area-under-the-curve (AUC) exposure profile comparable to that for the SAB-IE population model. For toxicity, we selected HD dosing schemes that minimized trough concentrations of ≥24.3 mg/liter. Separate HD dosing schemes were developed for each FDA-approved regimen and for two weekly interdialytic periods (48 and 72 h). Administration of the same parent daptomycin dose intra-HD and post-HD resulted in AUC, maximum concentration of drug in serum (Cmax), andCminvalues most comparable to those for SAB-IE simulations for the 48-hour interdialytic period. In contrast, all candidate HD dosing schemes provided AUC48-72values that were at least 50% lower than the SAB-IE AUC48-72values. Increasing the parent dose by 50% provided more comparable AUC48-72values while maintaining acceptableCminvalues. Administration of the daptomycin parent dose intra-HD or post-HD was optimal for the 48-h interdialytic period. For the 72-h interdialytic period, clinicians should consider increasing the dose by 50% to achieve more comparable AUC48-72values.

Cetuximab (Cet) clearance and survival in patients (pts) with metastatic colorectal cancer (mCRC).

2017 ◽  
Vol 35 (4_suppl) ◽  
pp. 699-699
Author(s):  
Di Maria Jiang ◽  
Hao-Wen Sim ◽  
Lillian L. Siu ◽  
Jeremy David Shapiro ◽  
Geoffrey Liu ◽  
...  
Keyword(s):  
Progression Free Survival ◽  
Compartment Model ◽  
Phase Iii ◽  
Population Pharmacokinetic ◽  
Mean Values ◽  
Clinical Variables ◽  
Disease Characteristics ◽  
Exposure Response ◽  
Trough Blood ◽  
Grade 3

699 Background: Cet, a monoclonal antibody against EGFR, is a standard therapy for pts with RAS wild-type (WT) mCRC. Limited previous data suggest that Cet clearance correlates with progression-free survival (PFS). We performed a population pharmacokinetic (pop-pK) analysis of Cet in pts who participated in the randomized phase III NCIC CO.20 trial in KRAS WT mCRC patients. Methods: Standard Cet doses ± brivanib were administered. Using intermittent trough blood samples, pop-pK analysis was conducted to evaluate different models. Pts were divided into quartiles according to clearance parameters to assess the exposure-response relationship to response rate (RR), PFS and overall survival (OS). Clinical variables including demographic, laboratory, disease characteristics and co-administration of brivanib were evaluated as co-variates on Cet clearance. Results: In 701 pts, Cet elimination was best described as a one-compartment model with a non-linear saturable elimination process (defined by Vmax and Km). Mean values (± standard deviation) for pop-pk parameters were 2.7 ± 0.5 L/m2 for V, 2.5 ± 0.3 mg/h/m2 for Vmax, and 101.0 ± 0.05 mg/L/m2 for Km. Grouped into quartiles, Vmax and Km were significantly associated with OS, but not RR or PFS. The median OS for pts in the lowest quartile of Vmax was 12.0 ms versus (vs.) 6.9 ms for pts in the highest quartile ( p< 0.001), while the median OS was 11.6 ms in the highest Km quartile vs. 6.9 ms in the lowest Km quartile ( p< 0.001). When compared to the quartile with the combination of highest Vmax and lowest Km, pts in the quartile with the lowest Vmax and highest Km had longer PFS (5.0 vs. 3.7 ms, HR 0.75 (95% confidence interval (CI) 0.58-0.98, p= 0.032) and OS (11.7 vs. 6.6 ms, HR 0.59 (95% CI, 0.45-0.77, p< 0.001). Pts in the lower Vmax and higher Km quartiles also experienced less grade 3 toxicity. Neither clinical variables nor brivanib administration were associated with Cet clearance parameters. Conclusions: For KRAS WT mCRC, standard Cet dosing is not optimal for all pts. Pts with slower Cet clearance have significantly improved PFS and OS. Further studies are needed to optimize Cet doses based on individual pK assessments, and to identify novel factors associated with clearance.

scholarly journals Population Modeling and Simulation Study of the Pharmacokinetics and Antituberculosis Pharmacodynamics of Isoniazid in Lungs

2015 ◽  
Vol 59 (9) ◽  
pp. 5181-5189 ◽  
Author(s):  
L. Lalande ◽  
L. Bourguignon ◽  
S. Bihari ◽  
P. Maire ◽  
M. Neely ◽  
...  
Keyword(s):  
Modeling And Simulation ◽  
Compartment Model ◽  
Bactericidal Effect ◽  
Population Pharmacokinetic ◽  
Alveolar Cells ◽  
Content Type ◽  
Population Pharmacokinetic Modeling ◽  
Acetylator Status ◽  
Daily Dose ◽  
The Mean

ABSTRACTAmong first-line antituberculosis drugs, isoniazid (INH) displays the greatest early bactericidal activity (EBA) and is key to reducing contagiousness in treated patients. The pulmonary pharmacokinetics and pharmacodynamics of INH have not been fully characterized with modeling and simulation approaches. INH concentrations measured in plasma, epithelial lining fluid, and alveolar cells for 89 patients, including fast acetylators (FAs) and slow acetylators (SAs), were modeled by use of population pharmacokinetic modeling. Then the model was used to simulate the EBA of INH in lungs and to investigate the influences of INH dose, acetylator status, andM. tuberculosisMIC on this effect. A three-compartment model adequately described INH concentrations in plasma and lungs. With an MIC of 0.0625 mg/liter, simulations showed that the mean bactericidal effect of a standard 300-mg daily dose of INH was only 11% lower for FA subjects than for SA subjects and that dose increases had little influence on the effects in either FA or SA subjects. With an MIC value of 1 mg/liter, the mean bactericidal effect associated with a 300-mg daily dose of INH in SA subjects was 41% greater than that in FA subjects. With the same MIC, increasing the daily INH dose from 300 mg to 450 mg resulted in a 22% increase in FA subjects. These results suggest that patients infected withM. tuberculosiswith low-level resistance, especially FA patients, may benefit from higher INH doses, while dose adjustment for acetylator status has no significant impact on the EBA in patients with low-MIC strains.

scholarly journals Developmental Pharmacokinetics of Lamivudine in 580 Pediatric Patients Ranging from Neonates to Adolescents

2011 ◽  
Vol 55 (7) ◽  
pp. 3498-3504 ◽  
Author(s):  
Naïm Bouazza ◽  
Déborah Hirt ◽  
Stéphane Blanche ◽  
Pierre Frange ◽  
Elisabeth Rey ◽  
...  
Keyword(s):  
Body Weight ◽  
Expectation Maximization Algorithm ◽  
Compartment Model ◽  
Population Pharmacokinetic Analysis ◽  
Pharmacokinetic Analysis ◽  
Population Pharmacokinetic ◽  
Apparent Clearance ◽  
Routine Basis ◽  
Time Courses ◽  
Elimination Clearance

ABSTRACTLamivudine concentration-time courses were described for a very large range of ages to study the effects of body weight and maturation on lamivudine pharmacokinetics and to check the consistency of dosing recommendations. Lamivudine concentrations were monitored on a routine basis to produce concentrations similar to the known values in adults. Concentrations were measured in 580 children from 2 days to 18 years old. A total of 2,106 plasma lamivudine concentrations were measured, and a population pharmacokinetic analysis was performed using the stochastic approximation expectation maximization algorithm implemented in MONOLIX 3.1 software. A two-compartment model adequately described the data. After standardization for a mean standard body weight by using an allometric model, age also had a significant effect on clearance maturation. Typical population estimates (percent interindividual variability) standardized for 70 kg of the apparent clearance, including central and peripheral volumes of distribution, intercompartmental clearance, and absorption rate constant, were 31 liters·h−1(32%), 76.4 liters (77%), 129 liters, 5.83 liters·h−1, and 0.432 h−1, respectively. According to the model, elimination clearance (liters/h/70 kg) increases gradually during the first years of life. Theoretical doses needed to reach the range of 24 h of exposure observed in adults were calculated: to be closer to adult exposure, children should receive 4 mg/kg/day from birth to 8 weeks of age, 5 mg/kg/day from 8 to 16 weeks of age, 6 mg/kg from 16 to 25 weeks of age, 8 mg/kg/day from 25 weeks of age to 14 kg of body weight, 150 mg/day from 14 to 25 kg of body weight, 225 mg/day from 25 to 35 kg of body weight, and 300 mg/day thereafter.

scholarly journals Gentamicin Population Pharmacokinetics in Pediatric Patients—A Prospective Study with Data Analysis Using the saemix Package in R

Pharmaceutics ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1596
Author(s):  
Paolo Paioni ◽  
Vera F. Jäggi ◽  
Romy Tilen ◽  
Michelle Seiler ◽  
Philipp Baumann ◽  
...  
Keyword(s):  
Prospective Study ◽  
Plasma Levels ◽  
Pediatric Patients ◽  
Plasma Concentrations ◽  
Compartment Model ◽  
R Package ◽  
Pharmacokinetic Modeling ◽  
Therapeutic Window ◽  
Population Pharmacokinetic ◽  
Population Pharmacokinetic Modeling

The aminoglycoside gentamicin is used for the empirical treatment of pediatric infections. It has a narrow therapeutic window. In this prospective study at University Children’s Hospital Zurich, Switzerland, we aimed to characterize the pharmacokinetics of gentamicin in pediatric patients and predict plasma concentrations at typical recommended doses. We recruited 109 patients aged from 1 day to 14 years, receiving gentamicin (7.5 mg/kg at age ≥ 7 d or 5 mg/kg). Plasma levels were determined 30 min, 4 h and 24 h after the infusion was stopped and then transferred, together with patient data, to the secure BioMedIT node Leonhard Med. Population pharmacokinetic modeling was performed with the open-source R package saemix on the SwissPKcdw platform in Leonhard Med. Data followed a two-compartment model. Bodyweight, plasma creatinine and urea were identified as covariates for clearance, with bodyweight as a covariate for central and peripheral volumes of distribution. Simulations with 7.5 mg/kg revealed a 95% CI of 13.0–21.2 mg/L plasma concentration at 30 min after the stopping of a 30-min infusion. At 24 h, 95% of simulated plasma levels were < 1.8 mg/L. Our study revealed that the recommended dosing is appropriate. It showed that population pharmacokinetic modeling using R provides high flexibility in a secure environment.

Abstract 12649: A Faster and Safe Way to Initiate Sotalol Therapy for Patients With Atrial Fibrillation or Flutter

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
John Somberg ◽  
Alexander A Vinks ◽  
Min Dong ◽  
janos molnar
Keyword(s):  
Atrial Fibrillation ◽  
Oral Administration ◽  
Torsade De Pointes ◽  
Estimation Method ◽  
Bioequivalence Study ◽  
Population Pharmacokinetic ◽  
Qtc Prolongation ◽  
Blood Concentrations ◽  
Population Pharmacokinetic Modeling ◽  
Hospital Days

Sotalol drug therapy is frequently employed to prevent the recurrence of highly symptomatic atrial fibrillation or flutter (AF, AFb). Sotalol can cause QTc prolongation that is proportional to blood concentration. Excessive concentration can cause Torsade de Pointes ventricular tachycardia (TdP). Because the risk of TdP, initiation of oral sotalol therapy is mandated by FDA to be in-hospital for a minimum of three days under ECG monitoring with facilities and personnel able to provide cardiac resuscitation. With oral administration (bid), 3 days are needed to reach maximal steady-state blood concentrations (Cmax ss) and thus maximal QTc prolongation. Three hospital days in a telemetry bed is costly and considerable expenditure of time and resources. Availability of IV sotalol makes it possible to reduce the loading time from 3 days to 1 day. The IV to oral loading regimen has been developed by model informed drug development. Serum sotalol concentrations and corresponding QTc were obtained from a previously performed bioequivalence study in healthy volunteers who received a single dose of oral and IV sotalol. NONMEM software package was used for population pharmacokinetic modeling and simulation. First Order Conditional Estimation method with Interaction (FOCE-INTER) was used for computation. We chose to administer IV sotalol over 1 hour to obtain Cmax ss target in a timeframe convenient for medical staff to supervise. The simulation for loading to the Cmax target produced by 80 mg PO bid is shown in the Figure; 60 mg IV sotalol is administered over 1 hour followed by 80 mg oral sotalol at 5 hours from start of infusion end then a second oral dose of 80 mg at 12 hours. One can target 120 mg maintenance dose by loading 90 mg IV over 1 hr followed by 120 mg oral dosing. Sotalol concentration will peak in 2-4 hours following each oral administration, thus in 21 hour there will be 3 sotalol peak concentrations. This permits evaluation of QTc response and risk of TdP all within a 1 day admission.

Cetuximab (Cet) clearance and survival in patients (pts) with metastatic colorectal cancer (mCRC).

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 3600-3600
Author(s):  
Di Maria Jiang ◽  
Hao-Wen Sim ◽  
Lillian L. Siu ◽  
Jeremy David Shapiro ◽  
Geoffrey Liu ◽  
...  
Keyword(s):  
Progression Free Survival ◽  
Compartment Model ◽  
Phase Iii ◽  
Population Pharmacokinetic ◽  
Limited Data ◽  
Wild Type ◽  
Free Survival ◽  
Blood Samples ◽  
Mean Values ◽  
Grade 3

3600 Background: Cet, a monoclonal antibody against EGFR, is a standard therapy for RAS wild-type (WT) mCRC. Limited data suggest a correlation between Cet clearance and progression-free survival (PFS). We performed a population pharmacokinetic (pop-pK) analysis of Cet in pts with KRAS WT mCRC who participated in the randomized phase III NCIC CO.20 trial. Methods: Standard Cet doses ± brivanib (Briv) were administered. Intermittent blood samples were obtained, and analyzed by ELISA for Cet. Pop-pK analysis was conducted to estimate Cet clearance. Pts were divided into quartiles according to clearance parameters to evaluate exposure-outcome with overall survival (OS), PFS, response rate (RR), and toxicity. Results: Blood samples were available from 703 pts. Cet clearance was best described as a one-compartment model with a saturable elimination (defined by Vmax and Km). Mean values (± standard deviation) were 5.6 ± 1.4 L for V, 10.5 ± 2.8 mg/h for Vmax, and 403.1 ± 2.0 mg/L for Km. Vmax and Km were significantly associated with OS, but not PFS or RR. Median OS for pts in the highest quartile of Vmax was 7.8 versus (vs.) 11.6 ms for pts in the lowest Vmax quartile (HR 1.12, 95% confidence interval (CI) 1.05-1.20, p< 0.001). In the highest Km quartile, median OS was 11.6 vs. 7.6 ms in the lowest Km quartile (HR 0.89, 95% CI 0.83-0.96, p= 0.001). Pts with the lowest clearance parameters (lowest Vmax and highest Km) had significantly longer OS (11.6 ms) compared to pts with the highest clearance (highest Vmax and lowest Km) (7.6 ms) (HR 0.67, 95% CI 0.53-0.83, p< 0.001). Overall incidences of grade 3/4 toxicity were not associated with Cet clearance. However, pts with the lowest clearance parameters had more frequent grade 3 diarrhea (OR 0.23, p= 0.005). Conclusions: For KRAS WT mCRC, standard Cet dosing is not optimal for all pts. Pts with lower Cet clearance have significantly improved OS and increased likelihood of grade 3 diarrhea. Further studies are needed to identify individual patient factors associated with Cet clearance, and to optimize Cet dosing based on individual pk assessments.

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