Population pharmacokinetic–pharmacodynamic modeling and model-based prediction of docetaxel-induced neutropenia in Japanese patients with non-small cell lung cancer

Using Pharmacokinetic-Pharmacodynamic Modeling to Study the Main Active Substances of the Anticancer Effect in Mice from Panax ginseng-Ophiopogon japonicus

Ginseng Radix et Rhizoma Rubra (Panax ginseng C.A. Mey, Hongshen, in Chinese) and Ophiopogonis Radix (Ophiopogon japonicus (L.f) Ker-Gawl., Maidong, in Chinese) are traditional Chinese herbal pairs, which were clinically employed to enhance the immune system of cancer patients. This study employed the pharmacokinetic and pharmacodynamic (PK-PD) spectrum-effect association model to investigate the antitumor active substances of P. ginseng and O. japonicus (PG-OJ). The metabolic processes of 20 major bioactive components were analyzed using Ultra-Performance Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (UPLC-MS/MS) in the lung tissue of tumor-bearing mice treated with PG-OJ. The ELISA method was employed to detect the levels of TGF-β1, TNF-α, and IFN-γ in the lung tissue of mice at various time points, and to analyze their changes after drug administration. The results showed that all components presented a multiple peaks absorption pattern within 0.083 to 24 h post-drug administration. The tumor inhibition rate of tumor and repair rate of IFN-γ, TNF-α, and TGF-β1 all increased, indicating a positive therapeutic effect of PG-OJ on A549 tumor-bearing mice. Finally, a PK-PD model based on the GBDT algorithm was developed for the first time to speculate that Methylophiopogonanone A, Methylophiopogonanone B, Ginsenoside Rb1, and Notoginsenoside R1 are the main active components in PG-OJ for lung cancer treatment.

Exploring pharmacogenetics of paclitaxel- and docetaxel-induced peripheral neuropathy by evaluating the direct pharmacogenetic-pharmacokinetic and pharmacokinetic-neuropathy relationships

Introduction: Peripheral neuropathy (PN) is an adverse effect of several classes of chemotherapy including the taxanes. Predictive PN biomarkers could inform individualized taxane treatment to reduce PN and enhance therapeutic outcomes. Pharmacogenetics studies of taxane-induced PN have focused on genes involved in pharmacokinetics, including enzymes and transporters. Contradictory findings from these studies prevent translation of genetic biomarkers into clinical practice. Areas covered: This review discusses the progress toward identifying pharmacogenetic predictors of PN by assessing the evidence for two independent associations; the effect of pharmacogenetics on taxane pharmacokinetics and the evidence that taxane pharmacokinetics affects PN. Assessing these direct relationships allows the reader to understand the progress toward individualized taxane treatment and future research opportunities. Expert opinion: Paclitaxel pharmacokinetics is a major determinant of PN. Additional clinical trials are needed to confirm the clinical benefit of individualized dosing to achieve target paclitaxel exposure. Genetics does not meaningfully contribute to paclitaxel pharmacokinetics and may not be useful to inform dosing. However, genetics may contribute to PN sensitivity and could be useful for estimating patients' optimal paclitaxel exposure. For docetaxel, genetics has not been demonstrated to have a meaningful effect on pharmacokinetics and there is no evidence that pharmacokinetics determines PN.

Dose individualisation in oncology using chemotherapy-induced neutropenia: Example of docetaxel in non-small cell lung cancer patients

AIMS

Chemotherapy-induced neutropenia has been associated with an increase in overall survival in non-small cell lung cancer patients. Therefore, neutrophil counts could be an interesting biomarker for drug efficacy as well as linked directly to toxicity. For drugs where neutropenia is dose limiting, neutrophil counts might be used for monitoring drug effect and for dosing optimisation.

METHODS

The relationship between drug effect on the first cycle neutrophil counts and patient survival was explored in a Phase III clinical trial where patients with non-small cell lung cancer were treated with docetaxel. Once the association has been established, dosing optimisation was performed for patients with severe toxicities (neutropenia) without compromising drug efficacy (overall survival).

RESULTS

After taking into account baseline prognostic factors, such as Eastern Cooperative Oncology Group performance status, smoking status, liver metastasis, tumour burden, neutrophil counts and albumin levels, a model-predicted drug effect on the first cycle neutrophil counts was strongly associated with patient survival (P = .005). Utilising this relationship in a dose optimisation algorithm, 194 out of 366 patients would have benefited from a dose reduction after the first cycle of docetaxel. The simulated 1-year survival probabilities associated with the original dose and the individualised dose were not different.

CONCLUSION

The strong relationship between drug effect on the first cycle neutrophil counts and patient survival suggests that this variable could be used to individualise dosing, possibly without needing pharmacokinetic samples. The algorithm highlights that doses could be reduced in case of severe haematological toxicities without compromising drug efficacy.

Different treatment efficacies and side effects of cytotoxic chemotherapy

Differences in efficacy and toxicity between Asian and Caucasian patients with lung cancer treated with systemic chemotherapy is increasingly recognised. This is a major concern in the clinical setting as it influences outcomes and affect international harmonization of drug development. Interindividual variability of pharmacokinetics, where different genetic polymorphisms affect drug metabolism, transport, and receptor binding may account for the ethnic differences. Treatment efficacy and outcomes may also be explained by differences in diet and lifestyle, access to healthcare, cultural barriers and environmental exposure. Efforts made to design prospective studies investigating ethnic specific determinants to systemic therapy and individualise lung cancer treatment based on genetic makeup of patient are important.

An improved LC-MS/MS method for determination of docetaxel and its application to population pharmacokinetic study in Chinese cancer patients

Because of its unpredictable side effects and efficacy, the anticancer drug docetaxel (DTX) requires improved characterisation of its pharmacokinetic profiles through population pharmacokinetic studies. A sensitive and rugged LC-MS/MS method for the detection of DTX in human plasma was developed and optimised using paclitaxel as an internal standard (IS). The plasma samples underwent rapid extraction using hybrid solid-phase extraction-protein precipitation. The analyte and IS were separated with an isocratic system on a Zorbax Eclipse Plus C₁₈ column using water containing 0.05% acetic acid along with 20 μM of sodium acetate and methanol (30/70, v/v) as the mobile phase. Quantification was performed using a triple quadrupole mass spectrometer through multiple reaction monitoring in positive mode, using the m/z 830.3 → 548.8 and m/z 876.3 → 307.7 transitions for DTX and paclitaxel, respectively. The range of the calibration curve was 1-500 ng/mL for DTX, and the linear correlation coefficient was >0.99. The accuracies ranged from -4.6 to 4.2%, and the precision was no higher than 7.0% for the analytes. No significant matrix effect was observed. Both DTX and the IS showed considerable recovery. This method was finally applied to the establishment of a population pharmacokinetic model to optimise the clinical use of DTX.

Risk Factors for Febrile Neutropenia Induced by Docetaxel Chemotherapy in Patients with Non-small Cell Lung Cancer

We retrospectively obtained data of patient background and pretreatment characteristics from medical records and identified the predictive factors of febrile neutropenia (FN) in patients with non-small cell lung cancer (NSCLC) treated with docetaxel alone or in combination with the anti-vascular endothelial growth factor (VEGF) antibody bevacizumab. Patients were eligible for inclusion in the study if they were 20 years or older, diagnosed with NSCLC, and received docetaxel monotherapy alone or in combination with bevacizumab at the Department of Respiratory Medicine, Kobe City Medical Center General Hospital, between July 1, 2011, and March 31, 2018. Eighty-one patients with recurrent or advanced NSCLC were included. Multivariate stepwise logistic regression analysis with backward selection revealed that lower baseline Eastern Cooperative Oncology Group performance status (ECOG-PS) scores of 1 and 2 (odds ratio (OR), 5.098; 95% confidence interval (CI), 1.045-24.879, p = 0.021) and baseline platelet count below 18.8 × 10⁴/µL (OR, 3.861; 95% CI, 1.211-12.311, p = 0.022) were significant factors influencing the FN occurrence rate. Our results demonstrated that ECOG-PS 1-2 and lower baseline platelet count were significant risk factors of FN in patients with NSCLC receiving docetaxel-based chemotherapy. Moreover, the combination of anti-VEGF antibodies and docetaxel might be associated with increased FN frequency. Despite the limitations of this study including its retrospective design, single-center site, and small sample size, baseline ECOG-PS score and platelet count may be regarded as important indices to identify patients for prophylactic granulocyte-colony stimulating factor (G-CSF) treatment before docetaxel-based chemotherapy.

Impact of granulocyte colony-stimulating factor on FOLFIRINOX-induced neutropenia prevention: A population pharmacokinetic/pharmacodynamic approach

AIMS

Granulocyte colony-stimulating factor (G-CSF) is frequently prescribed to prevent chemotherapy-induced neutropenia, but the administration schedule remains empirical in case of bimonthly chemotherapy such as FOLFIRINOX regimen. This pharmacokinetic/pharmacodynamic (PK/PD) study was performed to determine the effect of different G-CSF regimens on the incidence and duration of neutropenia following FOLFIRINOX administration in order to propose an optimal G-CSF dosing schedule.

METHODS

A population PK/PD model was developed to describe individual neutrophil time course from absolute neutrophil counts (ANC) obtained in 40 advanced cancer patients receiving FOLFIRINOX regimen. The structural model considered ANC dynamics, neutropenic effect of cytotoxics and the stimulating effect of G-CSF on neutrophils. Final model estimates were used to simulate different G-CSF dosing schedules for 1000 virtual subjects. The incidence and duration of neutropenia were then calculated for different G-CSF dosing schedules.

RESULTS

The final model successfully described the myelosuppressive effect induced by the 3 cytotoxics for all patients. Simulations showed that pegfilgrastim administration reduced the risk of severe neutropenia by 22.9% for subjects with low ANC at the start of chemotherapy. Median duration in this group was also shortened by 3.1 days when compared to absence of G-CSF. Delayed G-CSF administration was responsible for higher incidence and longer duration of neutropenia compared to absence of administration.

CONCLUSION

The PK/PD model well described our population's ANC data. Simulations showed that pegylated-G-CSF administration 24 hours after the end of chemotherapy seems to be the optimal schedule to reduce FOLFIRINOX-induced neutropenia. We also underline the potential negative effect of G-CSF maladministration.

Clinical pharmacokinetics and drug exposure-toxicity correlation study of docetaxel based chemotherapy in Chinese head and neck cancer patients

Background

Area under time-concentration curve (AUC) of docetaxel is related with its toxicity and efficacy. The aim of this study is to investigate the target range of docetaxel AUC in Chinese head and neck cancer (HNC) patients.

Methods

Eligible HNC patients were enrolled and received at least 2 cycles of docetaxel-based chemotherapy. A simplified pharmacokinetic (PK) strategy (2 monitored samples) was developed to simulate docetaxel AUC using the nonlinear mixed-effect modelling program. Preliminary target range of AUC was pre-set as 2.5–3.7 µg·hr/mL according to pooled analysis from 8 previous studies. Fisher exact test was used to analyze the relationship between AUC with neutropenia and efficacy, and to verify the target range.

Results

Thirty-nine eligible patients were enrolled. Grade 3-4 and grade 4 neutropenia rate in 1^st cycle was 64% and 36%, respectively. AUC simulation by simplified PK strategy was acceptable compared to full sampling method from the analysis of archived 300 patients’ data, with −5.67% of mean prediction error (MPE). Median AUC of all patients was 2.58 µg·hr/mL (range from 1.28 to 9.39). A significant correlation (P=0.007) was detected between AUC and body surface area (BSA)-dosage, but BSA contributed only 18.3% of AUC inter-individual variability. Docetaxel AUC was significantly related with the severity (grade 3–4) of neutropenia (correlation of coefficient was 0.452, P=0.004). Fourteen patients (36%) were within the target AUC range. Patients with AUC above the target experienced more severe neutropenia (grade 3–4 rate 100% vs. 56%, P=0.036; grade 4 rate 86% vs. 25%, P=0.005). No significant difference of response rate was found between patients within the target or not.

Conclusions

A simplified samples PK strategy was developed for docetaxel AUC simulation. The target range of docetaxel AUC in Chinese HNC patients was suggested at 2.5–3.7 µg·hr/mL for reduced toxicity without compromising efficacy of docetaxel treatment.

Population pharmacokinetic modeling and simulation of HPPH in Chinese patients with esophageal carcinoma

1. 2-[1-Hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH), a second-generation photosensitizer, has been widely employed in photodynamic therapy (PDT) for the treatment of malignant lesions. The objective of this study was to characterize the pharmacokinetics of HPPH in Chinese patients using a population pharmacokinetic (PopPK) approach.2. For the first time, a PopPK model of HPPH for Chinese (n = 20) was developed (registration number: CTR20160425). The pharmacokinetics of HPPH was described by a three-compartment model with linear elimination. Through the stepwise addition (p < 0.05) and backward elimination (p < 0.001) approach, fat-free mass (FFM) was identified to be the most significant covariate and V₁ increased with FFM. Visual predictive check (VPC) was employed for the evaluation of the final model. Subsequent full covariate analysis indicated that FFM has considerable impact (∼30%) on HPPH exposure and fat mass also has a modest (∼25%) impact.3. The simulations suggested that a dose adjustment of HPPH may be necessary for Chinese and the dose of 3 mg/m² should be appropriate. HPPH exposure increases with fat mass while being inversely related to FFM. HPPH-PDT for overweight patients should be monitored with more caution and PDT conditions should be optimized if necessary.

Chemotherapy-Induced Neutropenia as a Prognostic and Predictive Marker of Outcomes in Solid-Tumor Patients

Chemotherapy-induced neutropenia (CIN) is one of the most common side effects seen in cancer patients. As an adverse event, it is deemed undesirable since it often constitutes a dose-limiting toxicity for cytotoxic agents leading to treatment delays and/or dose reductions. It is also associated with a financial cost component from diagnostic work-up and treatment of patients with chemotherapy-induced febrile neutropenia (CIFN). Neutropenia is commonly accompanied by a decrease in other hematopoietic lineages (anemia and/or thrombocytopenia). Dosing of chemotherapeutic agents is based on the severity of adverse effects seen. Depending on the degree of neutropenia, chemotherapeutic agents may be put on hold until count recovery and growth factor support might be added to allow for dosing as scheduled. However, neutropenia appears to be more than just an adverse event. While CIFN by itself constitutes an adverse event, the appearance of just CIN is not necessarily a marker of poor outcome. In fact, it rather appears to be a surrogate marker of response and/or survival in patients treated with cytotoxic regimens. Here we present evidence in different tumor types treated with different regimens on the role CIN plays as a marker for improved outcomes. If CIN is a surrogate prognostic and/or potentially predictive marker of response, chemotherapy doses may need to be escalated to achieve neutropenia. In addition, instead of reducing treatment doses for safety concerns, the addition of growth factor support and alternative dosing schemes may be strategies to consider.

Pharmacodynamic analysis of eribulin safety in breast cancer patients using real-world postmarketing surveillance data

Postmarketing surveillance is useful to collect safety data in real-world clinical settings. In this study, we applied postmarketing real-world data on a mechanistic model analysis for neutropenic profiles of eribulin in patients with recurrent or metastatic breast cancer. Demographic and safety data were collected using an active surveillance method from eribulin-treated recurrent or metastatic breast cancer patients. Changes in neutrophil counts over time were analyzed using a mechanistic pharmacodynamic model. Pathophysiological factors that might affect the severity of neutropenia were investigated, and neutropenic patterns were simulated for different treatment schedules. Clinical and laboratory data were collected from 401 patients (5199 neutrophil count measurements) who had not received granulocyte colony-stimulating factor and were eligible for pharmacodynamic analysis. The estimated mean parameters were as follows: mean transit time = 104.5 h, neutrophil proliferation rate constant = 0.0377 h-1 , neutrophil elimination rate constant = 0.0295 h-1 , and linear coefficient of drug effect = 0.0413 mL/ng. Low serum albumin levels and low baseline neutrophil counts were associated with severe neutropenia. The probability of grade ≥3 neutropenia was predicted to be 69%, 27%, and 27% for patients on standard, biweekly, and triweekly treatment scenarios, respectively, based on virtual simulations using the developed pharmacodynamic model. In conclusion, this is the first application of postmarketing surveillance data to a model-based safety analysis. This analysis of safety data reflecting authentic clinical settings will provide useful information on the safe use and potential risk factors of eribulin.

Co-delivery of docetaxel and silibinin using pH-sensitive micelles improves therapy of metastatic breast cancer

Breast cancer is the most vicious killer for women, and tumor metastasis is one of the leading causes of breast cancer therapy failure. In this study, a new pH-sensitive polymer (polyethylene glycol-block-poly[(1,4-butanediol)-diacrylate-β-N,N-diisopropylethylenediamine], BDP) was synthesized. Based on BDP, docetaxel/silibinin co-delivery micelles (DSMs) was constructed. DSM had a well-defined spherical shape under the transmission electron microscope with average hydrodynamic diameter of 85.3±0.4 nm, and were stable in the bloodstream but could dissociate to release the chemotherapeutic agents in the low pH environment of the endo/lysosomes in the tumor cells. Compared with free drugs, DSM displayed greatly enhanced cellular uptake, higher cytotoxicity and a stronger anti-metastasis effect against mouse breast cancer cell line 4T1. In 4T1 tumor-bearing mice treated with DSM (twice a week for 3 weeks), the inhibition rate on tumor growth and metastasis reached 71.9% and 80.1%, respectively. These results reveal that DSM might be a promising drug delivery system for metastatic breast cancer therapy.