Population-pharmacokinetic/pharmacodynamic model of atractylodes lancea (Thunb.) DC. administration in patients with advanced-stage intrahepatic cholangiocarcinoma: a dosage prediction

Background A recent phase 2A clinical study of Atractylodes lancea (Thunb.) DC. (AL) in patients with advanced-stage intrahepatic cholangiocarcinoma (iCCA) demonstrated significant reduction of the risk of tumor progression and mortality with a dose ranging from 1,000 to 2,000 mg. The present study aimed to determine the potential dosage regimen of AL for further phase 2B clinical study. Methods Plasma-concentration time profiles of total AL bioactivity and clinical efficacy in patients with advanced-stage iCCA were obtained from Phase 2 A study. The population pharmacokinetic (pop-PK) model was developed. The pop-PK model and Monte-Carlo (MC) simulation, in conjunction with maximum concentration of AL (C-max) as a cut-off criterion, was performed and validated with clinical data. The optimal model was used to simulate further dosage regimens and clinical efficacy of AL. Results The pop-PK properties of total AL bioactivity were best described by a compartmental model with zero-order absorption (without delay) and linear clearance. None of the investigated covariates improved model accuracy.The developed pop-PK with MC simulations following once-daily dosing of 1,000 mg and 2,000 mg adequately predicted the clinical efficacy (tumor progression and mortality). The once-daily dose of 2,500 mg is recommended for further phase 2B clinical study due to its relatively high efficacy on tumor progression inhibition (73%) and mortality rate reduction (71%) without excessive number of the administered capsules (23 capsules) and low risk of toxicities (<5%). Conclusions The applied pop-PK model with MC simulation, along with the appropriate cut-off pharmacokinetic parameters, can be used as a potential tool for supporting dosage prediction and selection for clinical studies, and thus reducing the rate of drug development failures. Trial registration www.thaiclinicaltrials.org, WHO ICTRP search, TCTR20210129007, Registed 29 January 2021.