Population pharmacokinetics/pharmacodynamics of docetaxel in phase II studies in patients with cancer

Opportunities for Precision Dosing of Cytotoxic Drugs in Non-Small Cell Lung Cancer: Bridging the Gap in Precision Medicine

Precision dosing of classical cytotoxic drugs in oncology remains underdeveloped, especially in treating non-small cell lung cancer (NSCLC). Despite advancements in targeted therapy and immunotherapy, classical cytotoxic agents continue to play a critical role in NSCLC treatment. However, the current body surface area (BSA)-based dosing of these agents fails to adequately address interindividual variability in pharmacokinetics. By better considering patient characteristics, treatment outcomes can be improved, reducing risks of under-exposure and over-exposure. This narrative review explores opportunities for precision dosing for key cytotoxic agents used in NSCLC treatment: cisplatin, carboplatin, pemetrexed, docetaxel, (nab-)paclitaxel, gemcitabine, and vinorelbine. A comprehensive review of regulatory reports and an extensive literature search were conducted to evaluate current dosing practices, pharmacokinetics, pharmacodynamics, and exposure-response relationships. Our findings highlight promising developments in precision dosing, although the number of directly implementable strategies remains limited. The most compelling evidence supports using the biomarker cystatin C for more precise carboplatin dosing and adopting weekly dosing schedules for docetaxel, paclitaxel, and nab-paclitaxel. Additionally, we recommend direct implementation of therapeutic drug monitoring (TDM)-guided dosing for paclitaxel. This review stresses the urgent need to reassess conventional dosing paradigms for classical cytotoxic agents to better align with the principles of the precision dosing framework. Our recommendations show the potential of precision dosing to improve NSCLC treatment, addressing gaps in the current dosing of classical cytotoxic drugs. Given the large NSCLC patient population, optimising the dosing of these agents could significantly improve treatment outcomes and reduce toxicity for many patients.

From Prospective Evaluation to Practice: Model-Informed Dose Optimization in Oncology

One dose does not fit all, especially in oncolytic drugs, where side effects and therapy failures highlight the need for personalized dosing approaches. In recent years, the quest to apply model-informed precision dosing to oncology drugs has gained significant momentum, reflecting its potential to revolutionize patient care by tailoring treatments to individual pharmacokinetic profiles. Despite this progress, model-informed precision dosing has not (yet) become widely integrated into routine clinical care. We aimed to explain model-informed precision dosing from a clinical viewpoint while addressing all prospective model-informed precision dosing implementation and validation studies in the field of oncology. We identified 16 different drugs for which prospective model-informed precision dosing validation/implementation has been performed. Although these studies are mostly focused on attaining adequate drug exposures and reducing inter-individual variability, improved clinical outcomes after performing model-informed precision dosing were shown for busulfan, and high-dose methotrexate. Toxicities were significantly reduced for busulfan and cyclophosphamide treatment. In contrast, for carboplatin, for which model-informed precision dosing has been used in the Calvert formula, no prospective validation on outcomes was deemed necessary as the therapeutic window had been extensively validated. Model-informed precision dosing has shown to be of added value in oncology and is expected to significantly change dosing regimens in the future.

The Efficacy Research of Prophylactic PEG-rhG-CSF in Preventing Neutropenia in Early-Stage Breast Cancer Patients Treated With Docetaxel-Based Chemotherapy: A Retrospective Analysis

PURPOSE

Docetaxel-based chemotherapy regimens (DBRs) are commonly used in the treatment of early-stage breast cancer (EBC). The prophylactic use of pegylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) has been shown to reduce the incidence of neutropenia induced by DBRs. However, the clinical usage of PEG-rhG-CSF in EBC patients undergoing DBRs in China remains unclear.

METHODS

This retrospective study was conducted in 137 EBC patients receiving DBRs from September 2022 to February 2024. We compared the incidence of chemotherapy-induced neutropenia (CIN) between patients who was treated with prophylactic PEG-rhG-CSF or not by complete blood counts, evaluating the effectiveness of PEG-rhG-CSF in preventing CIN. Prophylactic PEG-rhG-CSF was given at 100 μg/kg body weight (maximum total dosage of 6 mg) once 24-48 h following chemotherapy. Meanwhile, we also collected basic patient information, the area under time-concentration curve of docetaxel, and liver and kidney function indicators. Multivariate logistic regression and Receiver operating characteristic (ROC) curve analysis were employed to explore independent factors influencing neutropenia.

FINDINGS

In this study, 87 of 137 EBC patients were administrated with prophylactic PEG-rhG-CSF, while 50 were not. Compared to patients who did not receive PEG-rhG-CSF, those who received prophylactic injections had a significantly lower incidence of grade 3-4 CIN (20% vs. 4.6%, P < 0.05). Higher body surface area (BSA), lower body mass index (BMI), elevated alanine aminotransferase (ALT), and nonprophylactic use of PEG-rhG-CSF were found to be positively correlated with CIN occurrence. ROC curve analysis indicated an area under the curve of 0.756 for predicting CIN in EBC patients when BSA was 1.66 m², BMI was 24.8 kg/m², and ALT was 41 U/L, with a sensitivity of 73.08% and specificity of 73.87%.

IMPLICATIONS

Prophylactic use of PEG-rhG-CSF significantly reduces the incidence of CIN, particularly grades 3 and 4. BSA, BMI, ALT, and PEG-rhG-CSF prophylaxis are independent influencing factors for the occurrence of neutropenia.

A sub-pharmacological test dose does not predict individual docetaxel exposure in prostate cancer patients

PURPOSE

Docetaxel is a cytotoxic drug used for first-line treatment of various malignancies. It has a narrow therapeutic index and shows wide interpatient variability in clearance and toxicity. Tools for individual dose optimization are needed to maximize efficacy and avoid toxicity.

METHODS

We performed a proof-of-concept study (EudraCT 2016-003785-77) to evaluate whether pharmacokinetics after a sub-pharmacological test dose of 1000 µg docetaxel (millidose) could be used to predict therapeutic dose exposure. Thirty prostate cancer patients eligible for treatment with docetaxel as part of routine clinical care were included. An intravenous docetaxel millidose was administered 1-7 days prior to therapeutic docetaxel. After both doses plasma docetaxel concentrations were measured by ultra- high performance liquid chromatography-tandem mass spectrometry. The docetaxel clearance was estimated with non-linear mixed effects modeling.

RESULTS

Geometric mean docetaxel clearance was 57.9 L/h (GCV 78.6%) after admission of a millidose and 40.3 L/h (GCV 60.7%) after admission of a therapeutic dose. The millidose and therapeutic dose in a single patient were not significantly correlated (Spearman's rho R = 0.02, P = 0.92).

CONCLUSION

Docetaxel pharmacokinetics at milli- and therapeutic dose level showed insufficient correlation for individual dose optimization. However, the clearance of a docetaxel millidose and full dose are within the same order of magnitude. Therefore, docetaxel millidose pharmacokinetics could potentially facilitate prediction of docetaxel pharmacokinetics at a population level in situations where therapeutic dose levels are impractical, such as pharmacokinetic drug-drug interaction studies or pediatric studies.

Oral docetaxel plus encequidar - A pharmacokinetic model and evaluation against IV docetaxel

The development of optimized dosing regimens plays a crucial role in oncology drug development. This study focused on the population pharmacokinetic modelling and simulation of docetaxel, comparing the pharmacokinetic exposure of oral docetaxel plus encequidar (oDox + E) with the standard of care intravenous (IV) docetaxel regimen. The aim was to evaluate the feasibility of oDox + E as a potential alternative to IV docetaxel. The article demonstrates an approach which aligns with the FDA's Project Optimus which aims to improve oncology drug development through model informed drug development (MIDD). The key question answered by this study was whether a feasible regimen of oDox + E existed. The purpose of this question was to provide an early GO / NO-GO decision point to guide drug development and improve development efficiency.

METHODS

 A stepwise approach was employed to develop a population pharmacokinetic model for total and unbound docetaxel plasma concentrations after IV docetaxel and oDox + E administration. Simulations were performed from the final model to assess the probability of target attainment (PTA) for different oDox + E dose regimens (including multiple dose regimens) in relation to IV docetaxel using AUC over effective concentration (AUCOEC) metric across a range of effective concentrations (EC). A Go / No-Go framework was defined-the first part of the framework assessed whether a feasible oDox + E regimen existed (i.e., a PTA ≥ 80%), and the second part defined the conditions to proceed with a Go decision.

RESULTS

 The overall population pharmacokinetic model consisted of a 3-compartment model with linear elimination, constant bioavailability, constant binding mechanics, and a combined error model. Simulations revealed that single dose oDox + E regimens did not achieve a PTA greater than 80%. However, two- and three-dose regimens at 600 mg achieved PTAs exceeding 80% for certain EC levels.

CONCLUSION

 The study demonstrates the benefits of MIDD using oDox + E as a motivating example. A population pharmacokinetic model was developed for the total and unbound concentration in plasma of docetaxel after administration of IV docetaxel and oDox + E. The model was used to simulate oDox + E dose regimens which were compared to the current standard of care IV docetaxel regimen. A GO / NO-GO framework was applied to determine whether oDox + E should progress to the next phase of drug development and whether any conditions should apply. A two or three-dose regimen of oDox + E at 600 mg was able to achieve non-inferior pharmacokinetic exposure to current standard of care IV docetaxel in simulations. A Conditional GO decision was made based on this result and further quantification of the "effective concentration" would improve the ability to optimise the dose regimen.

Using maximum plasma concentration (Cmax) to personalize taxane treatment and reduce toxicity

Taxanes are a widely used class of anticancer agents that play a vital role in the treatment of a variety of cancers. However, toxicity remains a major concern of using taxane drugs as some toxicities are highly prevalent, they can not only adversely affect patient prognosis but also compromise the overall treatment plan. Among all kinds of factors that associated with taxane toxicity, taxane exposure has been extensively studied, with different pharmacokinetic (PK) parameters being used as toxicity predictors. Compared to other widely used predictors such as the area under the drug plasma concentration curve versus time (AUC) and time above threshold plasma drug concentration, maximum plasma concentration (Cmax) is easier to collect and shows promise for use in clinical practice. In this article, we review the previous research on using Cmax to predict taxane treatment outcomes. While Cmax and toxicity have been extensively studied, research on the relationship between Cmax and efficacy is lacking. Most of the articles find a positive relationship between Cmax and toxicity but several articles have contradictory findings. Future clinical trials are needed to validate the relationship between Cmax and treatment outcome and determine whether Cmax can serve as a useful surrogate endpoint of taxane treatment efficacy.

A Cross-sectional Comparative Analysis of Eleven Population Pharmacokinetic Models for Docetaxel in Chinese Breast Cancer Patients

OBJECTIVE

Various population pharmacokinetic (PPK) models have been established to help determine the appropriate dosage of docetaxel, however, no clear consensus on optimal dosing has been achieved. The purpose of this study is to perform an external evaluation of published models in order to test their predictive performance, and to find an appropriate PPK model for Chinese breast cancer patients.

METHODS

A systematic literature search of docetaxel PPK models was performed using PubMed, Web of Science, China National Knowledge Infrastructure, and WanFang databases. The predictive performance of eleven identified models was evaluated using prediction-based and simulation-based diagnostics on an independent dataset (112 docetaxel concentrations from 56 breast cancer patients). The -2×log (likelihood) and Akaike information criterion were also calculated to evaluate model fit.

RESULTS

The median prediction error of eight of the eleven models was less than 10%. The model fitting results showed that the three-compartment model of Bruno et al. had the best prediction performance and that the three compartment model of Wang et al. had the best simulation effect. Furthermore, although the covariates that significantly affect PK parameters were different between them, seven models demonstrated that docetaxel PK parameters were influenced by liver function.

CONCLUSIONS

Three compartment PPK models may be predictive of optimal docetaxel dosage for Chinese breast cancer patients. However, for patients with impaired liver function, the choice of which model to use to predict the blood concentration of docetaxel still requires great care.

Generation and application of avatars in pharmacometric modelling

Simulations from population models have critical applications in drug discovery and development. Avatars or digital twins, defined as individual simulations matching clinical criteria of interest compared to observations from a real subject within a predefined margin of accuracy, may be a better option for simulations performed to inform future drug development stages in cases where an adequate model is not achievable. The aim of this work was to (1) investigate methods for generating avatars with pharmacometric models, and (2) explore the properties of the generated avatars to assess the impact of the different selection settings on the number of avatars per subject, their closeness to the individual observations, and the properties of the selected samples subset from the theoretical model parameters probability density function. Avatars were generated using different combinations of nature and number of clinical criteria, accuracy of agreement, and/or number of simulations for two examples models previously published (hemato-toxicity and integrated glucose-insulin model). The avatar distribution could be used to assess the appropriateness of the models assumed parameter distribution. Similarly it could be used to assess the models ability to properly describe the trajectories of the observations. Avatars can give nuanced information regarding the ability of a model to simulate data similar to the observations both at the population and at the individual level. Further potential applications for avatars may be as a diagnostic tool, an alternative to simulations with insurance to replicate key clinical features, and as an individual measure of model fit.

A pharmacometrics model to define docetaxel target in early breast cancer

AIMS

We aimed to study the relation between pharmacokinetics (PK) and pharmacodynamics (PD) of docetaxel in early breast cancer and recommend a target exposure.

METHODS

A PK/PD study was performed in 27 early breast cancer patients treated with doxorubicin and cyclophosphamide for 4 cycles followed by 4 cycles of docetaxel 75-100 mg/m² infused every 21 days. Individual Bayesian estimates of docetaxel PK parameters were obtained using a nonparametric population PK model developed with data from patients with metastatic breast cancer who received dose-intensified docetaxel (300-350 mg/m² ). Docetaxel area under the curve (AUC) and maximum concentration (Cmax) in each cycle and total cumulative AUC (AUCcum) were calculated and related to the incidence of adverse effects and tumour recurrence.

RESULTS

Docetaxel clearance showed no change over the 4 treatment cycles, but a gradual increase in the volume of distribution was observed. One third of the patients had at least 1 dose reduction of docetaxel due to toxicity. The mean AUC, AUCcum and Cmax in patients showing docetaxel-associated adverse events were significantly higher than in patients free of toxicity (P < .05). Fatigue and decrease in haemoglobin and haematocrit levels were related to docetaxel AUC and Cmax and pain to AUC. AUC and Cmax >4.5 mg*h/L and 3.5 mg/L, respectively, were risk factors for docetaxel toxicity, while an AUC <4.5 mg*h/L was associated with tumour recurrence.

CONCLUSION

We report for the first time a relation between docetaxel exposure and toxicity and recommend specific targets of drug exposure with implications for the clinical management of early breast cancer patients.

Cytochrome P-450-mediated herb and food-drug interactions can be identified in cancer patients through patient self-reporting with a tablet application: results of a prospective observational study

BACKGROUND

Consumption of herbs, food used as medicine and dietary supplements (HFDSs) is common in cancer patients. Herbs and food-drug interactions (HFDIs) can lead to serious adverse effects and can be prevented. We previously reviewed cytochrome P-450 (CYP)-mediated HFDI for 261 HFDSs and we classified the risk of CYP inhibition and induction on a level of evidence scale from 1 (high evidence, supported by several clinical studies) to 5 (low evidence, only limited preclinical data).

PATIENTS AND METHODS

We conducted a prospective, non-interventional study (NCT04128865) to assess whether self-assessment of patients could detect HFDI classified as 'probable' (i.e. level 1, 2 or 3 of the scale) in a population of cancer patients. Patients were invited through a tablet application to report their consumption of herbs, regular CYP-interacting food consumption and dietary supplements, as well as some clinical data and cancer treatments. The patient's completion of the survey could be supervised by a health care professional or not. A prespecified threshold of 5% of HFDIs classified as 'probable' detected with the application was deemed relevant.

RESULTS

Between 29 March 2018 and 22 June 2018, 143 patients completed the survey. Ninety-five patients (66%) reported at least one current systemic cancer treatment and were included in the analyses. Seventy-four patients reported an intake of at least one HFDS (77.9%), while 21 patients reported no HFDS (22.1%). Twenty-two HFDIs classified as 'probable' were found in 16 patients (16.8%) with the application, which was significantly superior to the prespecified threshold (P = 0.02). The interactions were reported with food (n = 19, 86%) more frequently than with herbs (n = 3, 14%) or with dietary supplements (no interaction reported).

CONCLUSIONS

Self-assessment of HFDS interaction with cancer treatment with an application is feasible and should be considered in daily routine. Prospective interventional studies should be conducted to better assess the clinical benefits of this approach.

Design, development and clinical translation of CriPec®-based core-crosslinked polymeric micelles

Nanomedicines are used to improve the efficacy and safety of pharmacotherapeutic interventions. Unraveling the biological behavior of nanomedicines, including their biodistribution and target site accumulation, is essential to establish design criteria that contribute to superior performance. CriPec® technology is based on amphiphilic methoxy-poly(ethylene glycol)-b-poly[N-(2-hydroxypropyl) methacrylamide lactate] (mPEG-b-pHPMAmLac_n) block copolymers, which are designed to upon self-assembly covalently entrap active pharmaceutical ingredients (API) in core-crosslinked polymeric micelles (CCPM). Key features of CCPM are a prolonged circulation time, high concentrations at pathological sites, and low levels of accumulation in the majority of healthy tissues. Proprietary hydrolysable linkers allow for tunable and sustained release of entrapped API, including hydrophobic and hydrophilic small molecules, as well as peptides and oligonucleotides. Preclinical imaging experiments provided valuable information on their tumor and tissue accumulation and distribution, as well as on uptake by cancer, healthy and immune cells. The frontrunner formulation CPC634, which refers to 65 nm-sized CCPM entrapping the chemotherapeutic drug docetaxel, showed excellent pharmacokinetic properties, safety, tumor accumulation and antitumor efficacy in multiple animal models. In the clinic, CPC634 also demonstrated favorable pharmacokinetics, good tolerability, signs of efficacy, and enhanced localization in tumor tissue as compared to conventional docetaxel. PET imaging of radiolabeled CPC634 showed quantifiable accumulation in ∼50 % of tumors and metastases in advanced-stage cancer patients, and demonstrated potential for use in a theranostic setting even when applied at a companion diagnostic dose. Altogether, the preclinical and clinical results obtained to date demonstrate that mPEG-b-pHPMAmLac_n CCPM based on CriPec® technology are a potent, tunable, broadly applicable and well-tolerable platform for targeted drug delivery and improved anticancer therapy.

Optimal exposure to docetaxel in adjuvant chemotherapy for early-stage breast cancer

WHAT IS KNOWN AND OBJECTIVE

Drug-induced neutropenia is the main reason for the dose limitation of docetaxel in patients with breast cancer. The area under the drug concentration-time curve (AUC) of docetaxel is associated with neutropenia. However, the optimal exposure to docetaxel for receiving postoperative adjuvant chemotherapy remains unclear. Therefore, we aimed to evaluate the relationship between the docetaxel AUC and neutropenia, identify potential influencing factors, and explore the best monitoring target for docetaxel when treating patients with early-stage breast cancer using a population pharmacokinetic (PopPK) model.

METHODS

Docetaxel plasma concentration, demographics, clinical data, and related laboratory data were collected. PopPK analyses were performed using a nonlinear mixed-effect modelling program. The docetaxel AUC was determined using the maximum a posteriori Bayesian (MAPB) method. The docetaxel exposure-toxicity threshold measured from the AUC for neutropenia was determined using the receiver operating characteristic (ROC) curve. The correlation between docetaxel exposure and neutropenia was analysed using multivariable logistic regression.

RESULTS

Among the 70 participants, 47 (67.1%) developed severe neutropenia. The PopPK analysis showed that the typical drug clearance (CL) rate was 37.4 L/h. Age was a significant covariate of CL rate, and aspartate aminotransferase and albumin levels were covariables of the volume of distribution. The multivariable regression analysis showed that AUC >3.0 mg.h/L (odds ratio [OR], 5.940; 95% confidence interval [CI], 1.693-20.843; P = 0.005), platinum use (OR, 0.156; 95% CI, 0.043-0.562; P = 0.005) and baseline haemoglobin level (OR, 0.938; 95% CI, 0.887-0.993; P = 0.027) were significant factors influencing the occurrence of grade 3/4 neutropenia. The AUC of first cycle may not predict the occurrence rates of grade 3/4 neutropenia in later cycles.

WHAT IS NEW AND CONCLUSION

We developed a docetaxel PopPK model for patients with early-stage breast cancer. Age and AST and ALB levels were significant covariates. AUC estimated using the MAPB method can predict the toxicity of docetaxel in patients with breast cancer. Docetaxel AUC >3.0 mg.h/L, absence of platinum use and low baseline haemoglobin level were risk factors for docetaxel-induced grade 3/4 neutropenia.

STUDY REGISTRATION

Chinese Clinical Trial Center Registry (ChiCTR2200056460).

Lean Body Mass and Total Body Weight Versus Body Surface Area as a Determinant of Docetaxel Pharmacokinetics and Toxicity

AIM

This study examined whether anthropometric and body composition parameters such as body surface area (BSA), lean body mass (LBM), and total body weight (TBW) are correlated with docetaxel clearance and exposure by analyzing area under the curve. In addition, LBM, TBW, and a fixed dose were compared with BSA as dosing parameters for dose individualization of docetaxel.

METHODS

Thirty-six patients receiving docetaxel chemotherapy for breast or metastatic castration-resistant prostate carcinoma were included. Before treatment, LBM was measured using a dual-energy X-ray absorptiometry scanner. Blood samples were collected up to 180 minutes after dosing to analyze docetaxel concentrations and determine individual pharmacokinetic parameters.

RESULTS

No significant correlations were found between docetaxel clearance and the anthropometric and body composition variables (BSA, LBM, and TBW). The area under the curve was significantly but poorly correlated with BSA [r = 0.452 ( P = 0.016)] and TBW [r = 0.476 ( P = 0.011)]. The mean absolute percentage error and mean error of simulated dosing based on LBM and fixed dosing were not significantly different from those of BSA. For TBW, only mean absolute percentage error was significantly higher compared with dosing based on BSA (24.1 versus 17.1, P = 0.001).

CONCLUSIONS

There was no clinically relevant correlation between docetaxel pharmacokinetics and the anthropometric and body composition variables BSA, LBM, and TBW. Therefore, dose individualization of docetaxel based on LBM, TBW, or fixed dosing cannot be recommended over BSA-based dosing.

A pro-oxidant combination of resveratrol and copper reduces chemotherapy-related non-haematological toxicities in advanced gastric cancer: results of a prospective open label phase II single-arm study (RESCU III study)

It has been reported that chemotherapy toxicity is primarily not due to the drugs themselves, but is caused by cell-free chromatin particles (cfChPs) that are released from chemotherapy-induced dying cells. cfChPs from dying cells are readily internalized by healthy cells, wherein they inflict dsDNA breaks and activate inflammatory cytokines. cfChPs can be deactivated by oxygen radicals that are generated upon admixing the nutraceuticals resveratrol (R) and copper (Cu). Pre-clinical studies have shown that administration of R-Cu can reduce chemotherapy toxicity via the generation of oxygen radicals which deactivate cfChPs released from chemotherapy-induced dying cells. We investigated if R-Cu would reduce toxicity of docetaxel-based multi-agent chemotherapy in advanced gastric cancer. This single-arm phase II study was designed to assess the efficacy of orally administered R-Cu in ameliorating toxic side effects, as per National Cancer Institute Common Terminology Criteria for Adverse Events v4.03, in patients with advanced gastric cancer receiving docetaxel-based multi-agent chemotherapy. The primary objective was to reduce the proportion of patients experiencing grade ≥ 3 toxicity from 90 to 70%. Between October 2019 and April 2021, 30 patients, with a median age of 54 years, were enrolled of whom 73% were male. R-Cu treatment did not reduce the overall cumulative incidence of grade ≥ 3 toxicity (77%), or of ≥ 3 haematological toxicity (73%). However, the incidence of non-haematological toxicities comprising hand-foot syndrome (N = 4), diarrhoea (N = 3) and vomiting (N = 1) were markedly reduced (13%). Median progression-free survival (PFS) was 8 months (95% CI: 5.9-10.1), and overall survival (OS) was 16 months (95% confidence interval: 6.3-28.3). A marked reduction in non-haematological toxicities was seen in patients receiving R-Cu compared to historical data without adversely affecting PFS or OS. (292).Clinical trial information CTRI/2019/07/020289.

Comparison of docetaxel pharmacokinetics between castration-resistant and hormone-sensitive metastatic prostate cancer patients

Purpose

Recently, docetaxel treatment of metastatic prostate cancer patients shifted towards the hormone-sensitive stage of the disease. There are contradictive reports on differences in toxicity of docetaxel in metastatic hormone-sensitive prostate cancer (mHSPC) and metastatic castration-resistant prostate cancer (mCRPC) patients. Possible differences in toxicity might be attributed to different pharmacokinetics (PK) in the two patient populations.

Methods

Patients with mCRPC or mHSPC and a standard indication for docetaxel treatment were included in the study. All patients had suppressed serum testosterone levels (≤ 0.5 ng/mL or 1.73 nmol/L). Venous blood samples were obtained at the first docetaxel treatment, until 48 h after infusion. Plasma concentrations of docetaxel, unbound docetaxel and docetaxel metabolites were measured using validated liquid chromatography coupled tandem mass spectrometry (LC–MS/MS) assays and compared between the two groups. Moreover, serum levels of docetaxel transporting α1-acid glycoprotein were measured and docetaxel toxicity recorded.

Results

A total of ten mCRPC and nine mHSPC patients were included in the study. The two cohorts differed in the number of prior treatments and opiate use, which were higher for mCRPC patients. The docetaxel PK was not different between mCRPC and mHSPC patients, with areas under the plasma concentration versus time curve (AUC_0-48) 1710 [coefficient of variation (CV) 28.4%] and 1486 (CV 25.2%) ng/mL*h (p = 0.27), respectively. Also, the PK profile of unbound docetaxel, M1/M3, M2 and M4 metabolites were similar in both groups. Docetaxel doses were reduced in 50% of the mCRPC patients and 11% of the mHSPC patients.

Conclusion

The PK profile of docetaxel was similar in mCPRC and mHSPC patients. Therefore, possible differences in toxicity between mCRPC and mHSPC patients cannot be explained by differences in docetaxel PK in our study population. These results suggest that treatment adaptations are not recommended in the new population of patients with mHSPC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00280-022-04433-3.

The influence of docetaxel schedule on treatment tolerability and efficacy in patients with metastatic breast cancer: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Administration of single-agent docetaxel in a weekly schedule may offer similar efficacy, with a more favorable toxicity profile, compared to a three-weekly schedule in patients with metastatic breast cancer.

METHODS

The original search of Medline, Embase, and Scopus was performed in September 2018 and references were updated with additional searches up to January 2021. Two reviewers independently screened the identified literature based on a predefined set of criteria. Randomized controlled trials investigating the use of weekly versus three-weekly docetaxel in metastatic breast cancer patients were included.

RESULTS

Four randomized controlled trials (N = 459 patients) were included in the final analyses. No significant differences were found in terms of objective response rate (risk ratio (RR) 0.75, 95% confidence interval (CI): 0.54 - 1.05), progression-free survival (hazard ratio (HR) 0.95, 95% CI: 0.71 - 1.26) or overall survival (HR 0.95, 95% CI: 0.70 - 1.29) between weekly and three-weekly docetaxel, respectively. Weekly docetaxel was associated with a significantly lower risk of grade 3/4 neutropenia (RR 0.16, 95% CI: 0.10 - 0.27), febrile neutropenia (RR 0.21, 95% CI: 0.08 - 0.55), and neuropathy (RR 0.29, 95% CI: 0.11 - 0.78). Although the risk of epiphora (≥ grade 3/leading to treatment withdrawal, RR 3.62, 95% CI: 1.07-12.22) and onycholysis (≥ grade 2/leading to treatment withdrawal, RR 3.90, 95% CI: 1.34 - 11.32) was increased.

CONCLUSIONS

Weekly docetaxel is associated with a lower risk of neutropenia, febrile neutropenia and neuropathy than the three-weekly docetaxel schedule in metastatic breast cancer patients. However, the risk of onycholysis, epiphora, and treatment discontinuation seems increased with weekly administration. No significant differences in efficacy outcomes were found. Weekly docetaxel might be an alternative for patients at risk for developing neutropenia.

Ethnic Pharmacogenomic Differences in the Management of Asian Patients with Metastatic Prostate Cancer

Progression to metastatic disease occurs in about half of all men who develop prostate cancer (PC), one of the most common cancers in men worldwide. Androgen deprivation therapy has been the mainstay therapy for patients with metastatic PC (mPC) since the 1940s. In the last decade, there has been unprecedented advancement in systemic therapies, e.g., taxane, androgen-signalling pathway inhibitors, and biomarker-driven targeted therapies for various stages of disease, resulting in overall survival improvement. Adding to ongoing controversies over how best to treat these patients is the recognition that ethnicity may influence prognosis and outcomes. This review discusses recent evidence for the impacts of Asian ethnicity specifically, which includes environmental, sociocultural, and genetic factors, on the approach to pharmacological management of mPC. Clear inter-ethnic differences in drug tolerability, serious adverse events (AEs), and genetic heterogeneity must all be considered when dosing and scheduling for treatment, as well as designing future precision studies in PC.

Optimized Dosing: The Next Step in Precision Medicine in Non-Small-Cell Lung Cancer

In oncology, and especially in the treatment of non-small-cell lung cancer (NSCLC), dose optimization is often a neglected part of precision medicine. Many drugs are still being administered in "one dose fits all" regimens or based on parameters that are often only minor determinants for systemic exposure. These dosing approaches often introduce additional pharmacokinetic variability and do not add to treatment outcomes. Fortunately, pharmacological knowledge is increasing, providing valuable information regarding the potential of, for example, therapeutic drug monitoring. This article focuses on the evidence for the most promising and easily implemented optimized dosing approaches for the small-molecule inhibitors, chemotherapeutic agents, and monoclonal antibodies as treatment options currently approved for NSCLC. Despite limitations such as investigations having been conducted in oncological diseases other than NSCLC or the retrospective origin of many analyses, an alternative dosing regimen could be beneficial for treatment outcomes, prescriber convenience, or financial burden on healthcare systems. This review of the literature provides recommendations on the implementation of dose optimization and advice regarding promising strategies that deserve further research in NSCLC.

Dabrafenib inhibits ABCG2 and cytochrome P450 isoenzymes; potential implications for combination anticancer therapy

Dabrafenib is a BRAF inhibitor used in combination treatment of malignant melanoma and non-small cell lung carcinoma. In this study, we aimed to characterize its interactions with cytochrome P450 (CYP) isoenzymes and ATP-binding cassette (ABC) efflux transporters that have critical impact on the pharmacokinetics of drugs and play a role in drug resistance development. Using accumulation assays, we showed that dabrafenib inhibited ABCG2 and, less potently, ABCB1 transporter. We also confirmed dabrafenib as a CYP2C8, CYP2C9, CYP3A4, and CYP3A5 inhibitor. Importantly, inhibition of ABCG2 and CYP3A4 by dabrafenib led to the potentiation of cytotoxic effects of mitoxantrone and docetaxel toward respective resistant cell lines in drug combination studies. On the contrary, the synergistic effect was not consistently observed in ABCB1-expressing models. We further demonstrated that mRNA levels of ABCB1, ABCG2, ABCC1, and CYP3A4 were increased after 24 h and 48 h exposure to dabrafenib. Overall, our data confirm dabrafenib as a drug frequently and potently interacting with ABC transporters and CYP isoenzymes. This feature should be addressed with caution when administering dabrafenib to patients with polypharmacy but also could be utilized advantageously when designing new dabrafenib-containing drug combinations to improve the therapeutic outcome in drug-resistant cancer.

Differences between the quality aspects of various generic and branded docetaxel formulations

Docetaxel is a widely prescribed chemotherapy drug in oncology and post expiry of its patent, the drug has been marketed as a generic by multiple manufacturers. It is also classified as a narrow therapeutic window drug. Through enhanced permeability and retention effect, polymeric micelles can passively target agents to tumor tissue, thereby decreasing toxicity of the drug in normal tissue. However, various studies have raised concerns that generic docetaxel leads to greater incidences of toxicities among patients with cancer. Thus, we herein review the pharmaceutical challenges associated with different docetaxel formulations and provide insights into the dissimilarities in the quality and safety of branded and generic docetaxel formulations. Literature review reported that 90% of the generic formulations of docetaxel contain inadequate quantity of active drug and high levels of impurities. Higher amounts of solvents such as polysorbate 80 and ethanol in docetaxel formulation lead to severe toxicities such as febrile neutropenia, hematological, and cutaneous toxicities. In most of the studies, even minor changes in excipients, solvents, unbound fraction of docetaxel were associated with adverse events, while in few, the source of docetaxel remained unidentified. One study reported incidence of febrile neutropenia due to a switch in the formulation from branded to generic. The quality, safety, and efficacy of medicines will directly affect the life of patients, and therefore, use of docetaxel formulations that guarantee safety of patients are the necessity of the hour. Being an injectable anti-cancer drug, it is important to determine the consistency of the various formulations of docetaxel globally, conduct bioequivalence studies as per the regulatory standards, taking into account the permissible limits of the excipients or the presence of such unapproved excipients.

Influence of Concomitant Polypharmacy on Docetaxel-induced Febrile Neutropenia

Background/Aim

Docetaxel (DTX) is metabolized by liver cytochromes P450 (CYP) 3A4 (CYP3A4) and 3A5 (CYP3A5) CYP3A4 activity is considered the main factor affecting the effectiveness in DTX clearance. We, therefore, explored the association between DTX-induced febrile neutropenia (FN) and concomitant polypharmacy involving CYP3A4 inhibitors in cancer patients.

Patients and Methods

Among patients who received docetaxel, we compared the number of concomitant medications between patients with and without FN, and risk factors associated with FN were identified.

Results

The total number of concomitant CYP3A4 inhibitors and substrates used was significantly higher in patients with FN [mean: 2.1 (95% confidence interval (CI)=1.5-2.9)] than in those without FN [mean: 1.4 (95% CI=1.0-1.8)] (p=0.01). The only risk factor for FN was the use of ≥2 concomitant CYP3A4 inhibitors and substrates in total (OR=4.82, 95% CI=1.77-14.1; p=0.002).

Conclusion

Polypharmacy involving CYP3A4 inhibitors and substrates increases the risk of DTX-induced FN.

ADME gene polymorphisms do not influence the pharmacokinetics of docetaxel: Results from a population pharmacokinetic study in Indian cancer patients

BACKGROUND

Pharmacokinetics (PK) of docetaxel is characterized by high inter-individual variability (IIV). While covariate models that explain the PK variability of docetaxel exist, not much is known about the effects of genetic variations on docetaxel disposition.

METHODS

Fifty patients with head and neck or prostate cancer were enrolled of whom two patients withdrew consent before the start of the study. Docetaxel was administered at either 50 or 75 mg/m² as intravenous infusion over 1 h. One pharmacogenetic sample and a series of PK samples, either intensive (N = 5; 13 samples each) or sparse (N = 43; 6 samples each), were collected from each patient. Docetaxel levels were estimated using a validated HPLC method. Polymorphic loci on the Absorption, Distribution, Metabolism, and Elimination (ADME) genes were identified using the PharmacoScan array platform. Population pharmacokinetic analysis was carried out using NONMEM v7.2.

RESULTS

Docetaxel PK was well characterized by a three-compartment model. Clearance (Cl) was found to be 18 L/h with an IIV of 45.3%. None of the genetic variants showed significant covariate effect on the Cl of docetaxel. Patients with abnormal alanine aminotransferase (ALT) were found to have 25% lower Cl as compared to patients with normal ALT values. However, the covariate effect could not be established in the final model possibly due to lack of adequate number of patients with abnormal ALT.

CONCLUSION

Genetic polymorphisms in the ADME gene do not explain the IIV in PK of docetaxel. However, patients with abnormal liver function might require dose reduction.

CLINICAL TRIAL REGISTRATION

Not applicable since participants in this study received treatment that was standard of care.

Drug Exposure to Establish Pharmacokinetic-Response Relationships in Oncology

In the oncology field, understanding the relationship between the dose administered and the exerted effect is particularly important because of the narrow therapeutic index associated with anti-cancer drugs and the high interpatient variability. Therefore, in this review, we provide a critical perspective of the different methods of characterising treatment exposure in the oncology setting. The increasing number of modelling applications in oncology reflects the applicability and the impact of pharmacometrics on all phases of the drug development process and patient management as well. Pharmacometric modelling is a worthy component within the current paradigm of model-based drug development, but pharmacometric modelling techniques are also accessible for the clinician in the optimisation of current oncology therapies. Consequently, the application of population models in a hospital setting by generating close collaborations between physicians and pharmacometricians is highly recommended, providing a systematic means of developing and assessing model-based metrics as 'drivers' for various responses to treatments, which can then be evaluated as predictors for treatment success. Characterising the key determinants of variability in exposure is of particular importance for anticancer agents, as efficacy and toxicity are associated with exposure. We present the different strategies to describe and predict drug exposure that can be applied depending on the data available, with the objective of obtaining the most useful information in the patients' favour throughout the full drug cycle. Therefore, the objective of the present article is to review the different approaches used to characterise a patient's exposure to oncology drugs, which will result in a better understanding of the time course of the response and the magnitude of interpatient variability.

Assessment of different induction chemotherapy regimens in locally advanced nasopharyngeal carcinoma: Meta-analysis

BACKGROUND

A Bayesian network meta-analysis was performed to compare the efficacy and toxicities among different induction chemotherapy regimens in locally advanced nasopharyngeal carcinoma (LA-NPC).

METHODS

Electronic databases were searched for literature up to September 16, 2019. Two researchers independently selected the articles, evaluated the quality of the literature, and extracted and analyzed the data.

RESULTS

There were no significant differences in survival outcomes, mucositis, or gastrointestinal adverse events among the four regimens. The probability of GP being the best induction scheme to improve OS was 43.7%. The completion rate of concurrent chemotherapy with the GP regimen was significantly reduced than the other three regimens.

CONCLUSIONS

The survival outcomes of the four regimens in LA-NPC were comparable. Considering only OS, GP showed the highest probability of improving the survival of LA-NPC, while it also affected the completion of concurrent chemotherapy.

Roles of CYP3A4, CYP3A5 and CYP2C8 drug-metabolizing enzymes in cellular cytostatic resistance

Metabolic deactivation by cytochrome P450 (CYP) is considered a potential mechanism of anticancer drug resistance. However, this hypothesis is predominantly based on indirect pieces of evidence and/or is influenced by interfering factors such as the use of multienzymatic models. Thus, an experimental approach for its verification is needed. In the present work, we employed HepG2 cells transduced with CYP enzymes involved in docetaxel, paclitaxel and vincristine metabolism to provide mechanistic evidence on their possible roles in resistance to these chemotherapeutic agents. Using MTT proliferation tests, we showed that overexpression of CYP3A4 resulted in decreased antiproliferative activity of 1 μM docetaxel (by 11.2, 23.2 and 22.9% at 24, 48 and 72 h intervals, respectively), while the sensitivity of CYP3A4-transduced cells was restored by co-administration of ketoconazole. Paclitaxel exhibited differential efficacy in CYP2C8- and empty vector-transduced cells (significant differences between 10.9 and 24.4% for 0.01, 0.1 and 1 μM concentrations), but neither montelukast nor clotrimazole was capable of affecting this asymmetry. Finally, the pharmacological activity of vincristine was not influenced by CYP3A4 or CYP3A5 overexpression. In the follow-up caspase activation assays, docetaxel was confirmed to be a victim of CYP3A4-mediated resistance, which is, at least partly, brought by impaired activation of caspases 3/7, 8 and 9. In summary, our data demonstrate that CYP3A4-mediated metabolic deactivation of docetaxel might represent a significant mechanism of pharmacokinetic resistance to this drug. In contrast, the possible role of CYPs in resistance to paclitaxel and vincristine has been disconfirmed. Importantly, the expression of CYP3A4 in HepG2_CYP3A4 cells is comparable to that in primary hepatocytes and HepaRG cells, which suggests that our results might be relevant for in vivo conditions, e.g., for hepatocellular carcinoma. Thus, our data may serve as a valuable in vitro background for future in vivo studies exploring the area of intratumoural metabolism-based drug resistance.

ModraDoc006, an oral docetaxel formulation in combination with ritonavir (ModraDoc006/r), in metastatic castration-resistant prostate cancer patients: A phase Ib study

BACKGROUND

ModraDoc006 is an oral formulation of docetaxel, which is co-administered with the cytochrome P450 3A4 and P-glycoprotein inhibitor ritonavir (r): ModraDoc006/r. Weekly treatment with ModraDoc006/r had been evaluated in phase I trials in patients with different types of advanced solid tumors, but up to this point in time not in patients with metastatic castration-resistant prostate cancer (mCRPC).

AIM

We assessed safety and pharmacokinetics (PK) of ModraDoc006/r to establish the recommended phase 2 dose (RP2D) in patients with mCRPC.

METHODS

mCRPC patients, treatment naïve or following abiraterone or enzalutamide treatment, were included. Dose-escalation of ModraDoc006/r was based on safety and docetaxel PK. Antitumor activity was assessed by serum prostate-specific antigen (PSA) and radiological evaluation.

RESULTS

Cohort 1 (n = 5) received once weekly ModraDoc006 30 mg with ritonavir 100 mg in the morning, and ModraDoc006 20 mg with ritonavir 100 mg in the evening (30-20/100-100). The mean docetaxel area under the plasma concentration-time curve (mAUC0-inf) was 461 ng/mL × h with 1 dose limiting toxicity (DLT); grade 3 alanine transferase increase. In cohort 2 (n = 6, ModraDoc006/r 30-20/200-200), the mAUC0-inf was 1687 ng/mL × h with 2 DLTs; grade 3 diarrhea and mucositis. In cohort 3A (n = 6, ModraDoc006/r 30-20/200-100), the mAUC0-inf was 1517 ng/mL × h with 1 DLT; grade 3 diarrhea. In cohort 3B (n = 3, ModraDoc006/r 20-20/200-100), the mAUC0-inf was 558 ng/mL × h without DLTs. The mAUC0-inf exceeded estimated exposures of intravenous docetaxel in cohort 2 and 3A, was lower in cohort 1 and was in range in cohort 3B. PSA decreases of >50% occurred in 6/10 evaluable patients throughout the various cohorts. In five radiological evaluable patients, two confirmed partial responses were observed.

CONCLUSION

The RP2D was established at weekly ModraDoc006/r 30-20/200-100. Observed PSA and radiological responses suggest promising clinical activity. These results have led to an ongoing randomized Phase 2b study, comparing weekly ModraDoc006/r with 3-weekly IV docetaxel in patients with mCRPC.

Pharmacokinetics and Toxicities of Oral Docetaxel Formulations Co-Administered with Ritonavir in Phase I Trials

Introduction

Docetaxel is widely used as intravenous (IV) chemotherapy. Oral docetaxel is co-administered with the cytochrome P450 3A4 and P-glycoprotein inhibitor ritonavir to increase oral bioavailability. This research explores the relationship between the pharmacokinetics (PK) and toxicity of this novel oral chemotherapy.

Methods

The patients in two phase I trials were treated with different oral docetaxel formulations in combination with ritonavir in different dose levels, ranging from 20 to 80 mg docetaxel with 100 to 200 mg ritonavir a day. The patients were categorized based on the absence or occurrence of severe treatment-related toxicity (grade ≥3 or any grade leading to treatment alterations). The docetaxel area under the plasma concentration–time curve (AUC) and maximum plasma concentration (C_max) were associated with toxicity.

Results

Thirty-four out of 138 patients experienced severe toxicity, most frequently observed as mucositis, fatigue, diarrhea, nausea and vomiting. The severe toxicity group had a significantly higher docetaxel AUC (2231 ± 1405 vs 1011 ± 830 ng/mL*h, p<0.0001) and C_max (218 ± 178 vs 119 ± 77 ng/mL, p<0.0001) as compared to the patients without severe toxicity. When extrapolated from IV PK data, the patients without severe toxicity had a similar cumulative docetaxel AUC as with standard 3-weekly IV docetaxel, while the C_max was up to 10-fold lower with oral docetaxel and ritonavir.

Conclusion

Severe toxicity was observed in 25% of the patients treated with oral docetaxel and ritonavir. This toxicity seems related to the PK, as the docetaxel AUC_0-inf and C_max were up to twofold higher in the severe toxicity group as compared to the non-severe toxicity group. Future randomized trials will provide a further evaluation of the toxicity and efficacy of the new weekly oral docetaxel and ritonavir regimen in comparison to standard IV docetaxel.

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.

Role of TDM-based dose adjustments for taxane anticancer drugs

The classical taxanes (paclitaxel, docetaxel), the newer taxane cabazitaxel and the nanoparticle-bound nab-paclitaxel are among the most widely used anticancer drugs. Still, the optimal use and the value of pharmacological personalization of the taxanes is still controversial. We give an overview on the pharmacological properties of the taxanes, including metabolism, pharmacokinetics-pharmacodynamic relations and aspects in the clinical use of taxanes. The latter includes the ongoing debate on the most effective and safe regimen, the recommended initial dose, and pharmacological dosing individualization. The taxanes are among the most widely used anticancer drugs in patients with solid malignancies. Despite their longtime use in clinical routine, the optimal dosing strategy (weekly versus 3-weekly) or optimal average dose (cabazitaxel, nab-paclitaxel) has not been fully resolved, as it may differ according to tumour entity and line of treatment. The value of pharmacological individualization of the taxanes (TDM, TCI) has been partly explored for 3-weekly paclitaxel and docetaxel, but remains mostly unexplored for cabazitaxel and nab-paclitaxel at present.

Interactions between anti-EGFR therapies and cytotoxic chemotherapy in oesophageal squamous cell carcinoma: why clinical trials might have failed and how they could succeed

Purpose

Oesophageal squamous cell carcinoma (ESCC) has a poor prognosis. Advanced tumours are treated with fluoropyrimidine/platinum chemotherapy followed by irinotecan or taxane monotherapy, but resistance is common and new treatments are needed. Approximately 20% of ESCCs carry copy number gain (CNG) of the epidermal growth factor receptor (EGFR) gene. Previous trials show that while anti-EGFR monotherapy benefits biomarker-selected patients with EGFR CNG and/or high EGFR expression, combining anti-EGFR therapies with platinum fluoropyrimidine chemotherapies is not effective, and uncertainty remains regarding the optimal cytotoxic chemotherapy partner for anti-EGFR therapies in ESCC.

Methods

The effects of EGFR CNG on fluoropyrimidine/platinum chemotherapy sensitivity in a cohort of gastroesophageal cancer patients (n = 302) was evaluated. Drug combination studies using the EGFR inhibitor gefitinib with cytotoxic chemotherapies, docetaxel, cisplatin, oxaliplatin and irinotecan, on cell proliferation and cell death of EGFR CNG ESCC cell lines were assessed.

Results

EGFR CNG in gastroesophageal cancer patients was associated with improved overall survival following fluoropyrimidine/platinum chemotherapy. However, co-administration of gefitinib and oxaliplatin or cisplatin was frequently antagonistic in cell-based assays in EGFR CNG ESCC, whereas the combination of gefitinib with docetaxel or irinotecan was more efficacious. Co-administration of gefitinib/docetaxel and sequential administration of docetaxel before gefitinib showed synergy, but docetaxel given after gefitinib was antagonistic.

Conclusion

Gefitinib/platinum co-administration demonstrated antagonism suggesting a possible explanation for the lack of benefit from addition of anti-EGFR therapies to fluoropyrimidine/platinum chemotherapy in trials. Gefitinib/docetaxel co-administration demonstrated synergy suggesting taxanes could be the most effective cytotoxic partner for anti-EGFR therapies in EGFR CNG-positive ESCC, but careful consideration of drug scheduling is required.

Docetaxel-induced fluid retention during adjuvant chemotherapy with S-1 plus docetaxel

S-1 plus docetaxel is the standard postoperative adjuvant chemotherapy regimen for patients with stage III gastric cancer in Japan, which has increased the use of docetaxel. One of the most common adverse events of docetaxel, which is widely used to treat several malignancies, is fluid retention. Conversely, the most worrisome cause of ascites in patients who receive adjuvant chemotherapy is recurrence. Sometimes, the differential diagnosis of ascites is difficult if ascitic cytology is negative. In this study, we presented the case of a patient with massive ascites that appeared during adjuvant chemotherapy with S-1 plus docetaxel.

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.

No relation between docetaxel administration route and high-grade diarrhea incidence

Oral administration of docetaxel in combination with the CYP3A4 inhibitor ritonavir is used in clinical trials to improve oral bioavailability of docetaxel. Diarrhea was the most commonly observed and dose-limiting toxicity. This study combined preclinical and clinical data and investigated incidence, severity and cause of oral docetaxel-induced diarrhea. In this study, incidence and severity of diarrhea in patients were compared to exposure to orally administered docetaxel. Intestinal toxicity after oral or intraperitoneal administration of docetaxel was further explored in mice lacking Cyp3a and mice lacking both Cyp3a and P-glycoprotein. In patients, severity of diarrhea increased significantly with an increase in AUC and Cmax (P = .035 and P = .025, respectively), but not with an increase in the orally administered dose (P = .11). Furthermore, incidence of grade 3/4 diarrhea after oral docetaxel administration was similar as reported after intravenous docetaxel administration. Intestinal toxicity in mice was only observed at high systemic exposure to docetaxel and was similar after oral and intraperitoneal administration of docetaxel. In conclusion, our data show that the onset of severe diarrhea after oral administration of docetaxel in humans is similar after oral and intravenous administration of docetaxel and is caused by the concentration of docetaxel in the systemic blood circulation. Mouse experiments confirmed that intestinal toxicity is caused by a high systemic exposure and not by local intestinal exposure. Severe diarrhea in patients after oral docetaxel is reversible and is not related to the route of administration of docetaxel.

A phase I dose-escalation and pharmacokinetic study of a micellar nanoparticle with entrapped docetaxel (CPC634) in patients with advanced solid tumours

BACKGROUND

CPC634 is docetaxel entrapped in core-cross linked polymeric micelles. In preclinical studies, CPC634 demonstrated enhanced pharmacokinetics and improved therapeutic index. This phase I dose escalation study is the first-in-human study with CPC634.

METHODS

adult patients with advanced solid tumours received CPC634 intravenously either 3-weekly (Q3W) (part 1, dose range 15-100 mg/m²), 2-weekly (Q2W) (part 2, 45 mg/m²) or Q3W with dexamethasone premedication (part 3, 60 mg/m²).

RESULTS

thirty-three patients were enrolled. Skin toxicity was dose limiting (DLT) at ≥60 mg/m² in part 1 and at 45 mg/m² in part 2 and was the most common CPC634 related grade ≥ 3 adverse event (24%). With dexamethasone premedication no DLTs were observed at 60 mg/m² Q3W. CPC634 exhibited a dose-proportional pharmacokinetic profile. At 60 mg/m², the plasma area under the curve was 4067.5 ± 2974.0 ng/h/mL and the peak plasma level 217.3 ± 91.9 ng/mL with a half-life of 39.7 ± 9.4 h for released docetaxel.

CONCLUSION

CPC634 could be administered safely upon pretreatment with dexamethasone. Cumulative skin toxicity was the main DLT. The recommended phase 2 dose was determined at 60 mg/m² Q3W with dexamethasone premedication.

Ensartinib (X-396) Effectively Modulates Pharmacokinetic Resistance Mediated by ABCB1 and ABCG2 Drug Efflux Transporters and CYP3A4 Biotransformation Enzyme

Ensartinib (X-396) is a promising tyrosine kinase inhibitor currently undergoing advanced clinical evaluation for the treatment of non-small cell lung cancer. In this work, we investigate possible interactions of this promising drug candidate with ATP-binding cassette (ABC) drug efflux transporters and cytochrome P450 biotransformation enzymes (CYPs), which play major roles in multidrug resistance (MDR) and pharmacokinetic drug-drug interactions (DDIs). Accumulation studies showed that ensartinib is a potent inhibitor of ABCB1 and ABCG2 transporters. Additionally, incubation experiments with recombinant CYPs showed that ensartinib significantly inhibits CYP3A4 and CYP2C9. Subsequent molecular docking studies confirmed these findings. Drug combination experiments demonstrated that ensartinib synergistically potentiates the antiproliferative effects of daunorubicin, mitoxantrone, and docetaxel in ABCB1, ABCG2, and CYP3A4-overexpressing cellular models, respectively. Advantageously, ensartinib’s antitumor efficiency was not compromised by the presence of MDR-associated ABC transporters, although it acted as a substrate of ABCB1 in Madin-Darby Canine Kidney II (MDCKII) monolayer transport assays. Finally, we demonstrated that ensartinib had no significant effect on the mRNA-level expression of examined transporters and enzymes in physiological and lung tumor cellular models. In conclusion, ensartinib may perpetrate clinically relevant pharmacokinetic DDIs and modulate ABCB1-, ABCG2-, and CYP3A4-mediated MDR. The in vitro findings presented here will provide a valuable foundation for future in vivo investigations.

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.

Antitumor activity of ipatasertib combined with chemotherapy: results from a phase Ib study in solid tumors

BACKGROUND

This phase Ib study evaluated the safety, tolerability, pharmacokinetics, and preliminary efficacy of the oral AKT inhibitor ipatasertib and chemotherapy or hormonal therapy in patients with advanced or metastatic solid tumors to determine combined dose-limiting toxicities (DLTs), maximum tolerated dose, and recommended phase II doses and schedules.

PATIENTS AND METHODS

The clinical study comprised four combination treatment arms: arm A (with docetaxel), arm B [with mFOLFOX6 (modified leucovorin, 5-fluorouracil, and oxaliplatin)], arm C (with paclitaxel), and arm D (with enzalutamide). Primary endpoints were safety and tolerability; secondary endpoints were pharmacokinetics, clinical activity per Response Evaluation Criteria in Solid Tumors v1.1, and prostate-specific antigen levels.

RESULTS

In total, 122 patients were enrolled. Common adverse events were diarrhea, nausea, vomiting, decreased appetite, and fatigue. The safety profiles of the combination regimens were consistent with those of the background regimens, except for diarrhea, hyperglycemia, and rash, which were previously observed with ipatasertib treatment. The only combination DLT across all treatment arms was one event of grade 3 dehydration (ipatasertib 600 mg and paclitaxel). Recommended phase II doses for ipatasertib were 600 mg (and mFOLFOX6) and 400 mg (and paclitaxel), respectively. The maximum assessed dose of ipatasertib 600 mg combined with docetaxel or enzalutamide was well tolerated. Coadministration with enzalutamide (a cytochrome P450 3A inducer) resulted in approximately 50% lower ipatasertib exposure.

CONCLUSIONS

Ipatasertib in combination with chemotherapy or hormonal therapy was well tolerated with a safety profile consistent with that of ATP-competitive AKT inhibitors.

CLINICAL TRIAL NUMBER

NCT01362374.

Weekly docetaxel monotherapy for metastatic extramammary Paget's disease: Retrospective single-institute analysis

Monthly docetaxel (DTX) monotherapy is the first-line regimen that is preferably used for metastatic extramammary Paget's disease (EMPD). However, the high-dose DTX regimen frequently causes severe hematological adverse events (AE). To overcome such safety concerns, a weekly low-dose DTX monotherapy has been proposed for use in the treatment of various cancer types. In this study, we aimed to evaluate the feasibility and efficacy of weekly DTX (25 mg/m² ) monotherapy for metastatic EMPD by retrospectively analyzing the clinical courses of 14 patients treated with this regimen. Weekly DTX monotherapy was well tolerated and all patients completed the treatment schedule without treatment withdrawal, dose reduction or treatment-related death. While five cases (35.7%) experienced hematological AE, their severity was mild. The response rate was 35.7% (5/14 cases), which included five partial responses. The mean progression-free survival (PFS) and overall survival were 7.1 (95% confidence interval [CI], 5.1-9.1) and 26.4 months (95% CI, 16.7-36.1), respectively. Furthermore, the median PFS was 7.3 months (95% CI, 4.5-10.0) in patients aged 65 years and younger and 7.1 months (95% CI, 4.4-9.9) in patients older than 65 years. These results suggest that weekly DTX monotherapy may be a useful regimen that has a high treatment continuation rate with low levels of hematological toxicity, regardless of the patient's age for metastatic EMPD.

Genetic associations of docetaxel-based chemotherapy-induced myelosuppression in Chinese Han population

WHAT IS KNOWN AND OBJECTIVE

Myelosuppression, an adverse drug reaction (ADR), often causes medical treatment termination in cancer patients. It has been known that genetic components, such as single-nucleotide polymorphisms (SNPs), influence the risk of myelosuppression at the individual-patient level. However, due to ethnic variation in frequency of genetic polymorphisms, results reported in Caucasian patients may not be generalizable to the Chinese Han population. Until now, few researches on myelosuppression included Chinese Han patients. In this study, we conducted a systematic study of potential biomarkers for docetaxel-induced myelosuppression in Han Chinese patients.

METHODS

We examined 61 SNPs in 36 genes that code for drug transporters, metabolism enzymes, nuclear receptors and DNA repair pathway in 110 Chinese Han patients receiving docetaxel-based chemotherapy. Genotyping was conducted using the Sequenom MassARRAY system. Significant SNPs were identified by logistic regression, and gene-gene interactions were investigated by generalized multifactor dimensionality reduction (GMDR) analysis.

RESULTS AND DISCUSSION

Our results revealed that 11 SNPs in nine genes (SLC15A1, SLCO1A2, CYP2D6, FMO3, UGT1A1, NAT2, SULT2A1, PXR and HNF4α) were associated with docetaxel-induced myelosuppression. GMDR analyses suggested that a 3-locus model: SLC15A1 rs2297322-PXR rs3732359-FMO3 rs2266782 was an appropriate predictive model of docetaxel-induced myelosuppression (P = .017, Testing Bal.Acc = 0.653, CV Consistency = 10/10).

WHAT IS NEW AND CONCLUSION

Our findings suggest multiple novel predictive biomarkers of docetaxel-induced myelosuppression: SLC15A1 rs2297322, PXR rs3732359 and FMO3 rs2266782. These discoveries should help in advancing future personalized therapy of docetaxel-based chemotherapy specific to Chinese Han patients.

ABCB1 polymorphism predicts the toxicity and clinical outcome of lung cancer patients with taxane-based chemotherapy

BACKGROUND

Taxane-based chemotherapy is widely used in lung cancer. ABCB1 have a role in the prediction of treatment response and toxicity of chemotherapy in solid tumors. In this retrospective study, we investigated ABCB1 polymorphism on response and toxicity in taxane-based chemotherapy in lung cancer patients.

METHODS

A total of 122 lung cancer patients who received taxane-based chemotherapy were included in this study. Fluorescence in situ hybridization (FISH) was used for ABCB1 polymorphism detection. Turbidimetric inhibition immunoassay was used for pharmacokinetic analysis. Statistical analysis was performed using SPSS 20.0.

RESULTS

The frequency of the ABCB1 2677 site TT/TG/GG genotype was 32.8%, 43.4% and 23.8%, respectively and the frequency of the 3435 sites the TT/TC/CC genotype was 13.9%, 44.3% and 41.8%, respectively. The occurrence of neurotoxicity was higher in patients who had ABCB1 3435 site mutation (TT 88.2%, TC 22.2%, CC 21.6% P = 0.004). There was no significant difference between ABCB1 genotypes with regard to other chemotherapy-induced toxicity. For non-small cell lung cancer (NSCLC) patients, those harboring ABCB1 2677 and 3435 site wild-type patients had longer median progression-free survival (PFS) in the paclitaxel subgroup (3435 site: TT 3.87 vs. TC 9.50 vs. CC 14.13 months; P < 0.001; 2677 site: TT 4.37 vs. TG 9.73 vs. GG 12.1 months; P = 0.013). The area under the concentration-time curve (AUC) of 20 patients treated with docetaxel increased for ABCB1 mutation subgroups.

CONCLUSION

ABCB1 mutation is associated with higher neurotoxicity of taxane-based chemotherapy. It also predicts shorter PFS for NSCLC in paclitaxel-based treatment.

DZ-2384 has a superior preclinical profile to taxanes for the treatment of triple-negative breast cancer and is synergistic with anti-CTLA-4 immunotherapy

Triple-negative breast cancer (TNBC) is typically aggressive, difficult to treat, and commonly metastasizes to the visceral organs and soft tissues, including the lungs and the brain. Taxanes represent the most effective and widely used therapeutic class in metastatic TNBC but possess limiting adverse effects that often result in a delay, reduction, or cessation of their use. DZ-2384 is a candidate microtubule-targeting agent with a distinct mechanism of action and strong activity in several preclinical cancer models, with reduced toxicities. DZ-2384 is highly effective in patient-derived taxane-sensitive and taxane-resistant xenograft models of TNBC at lower doses and over a wider range relative to paclitaxel. When comparing compound exposure at minimum effective doses relative to safe exposure levels, the therapeutic window for DZ-2384 is 14-32 compared with 2.0 and less than 2.8 for paclitaxel and docetaxel, respectively. DZ-2384 is effective at reducing brain metastatic lesions when used at maximum tolerated doses and is equivalent to paclitaxel. Drug distribution experiments indicate that DZ-2384 is taken up more efficiently by tumor tissue but at equivalent levels in the brain compared with paclitaxel. Selective DZ-2384 uptake by tumor tissue may in part account for its wider therapeutic window compared with taxanes. In view of the current clinical efforts to combine chemotherapy with immune checkpoint inhibitors, we demonstrate that DZ-2384 acts synergistically with anti-CTLA-4 immunotherapy in a syngeneic murine model. These results demonstrate that DZ-2384 has a superior pharmacologic profile over currently used taxanes and is a promising therapeutic agent for the treatment of metastatic TNBC.

Organic Anion Transporting Polypeptides: Emerging Roles in Cancer Pharmacology

The organic anion transporting polypeptides (OATPs) are a superfamily of drug transporters involved in the uptake and disposition of a wide array of structurally divergent endogenous and exogenous substrates, including steroid hormones, bile acids, and commonly used drugs, such as anti-infectives, antihypertensives, and cholesterol lowering agents. In the past decade, OATPs, primarily OATP1A2, OATP1B1, and OATP1B3, have emerged as potential mediators of chemotherapy disposition, including drugs such as methotrexate, doxorubicin, paclitaxel, docetaxel, irinotecan and its important metabolite 7-ethyl-10-hydroxycamptothecin, and certain tyrosine kinase inhibitors. Furthermore, OATP family members are polymorphic and numerous studies have shown OATP variants to have differential uptake, disposition, and/or pharmacokinetics of numerous drug substrates with important implications for interindividual differences in efficacy and toxicity. Additionally, certain OATPs have been found to be overexpressed in a variety of human solid tumors, including breast, liver, colon, pancreatic, and ovarian cancers, suggesting potential roles for OATPs in tumor development and progression and as novel targets for cancer therapy. This review focuses on the emerging roles for selected OATPs in cancer pharmacology, including preclinical and clinical studies suggesting roles in chemotherapy disposition, the pharmacogenetics of OATPs in cancer therapy, and OATP overexpression in various tumor tissues with implications for OATPs as therapeutic targets.

Genetic variation in the ATP binding cassette transporter ABCC10 is associated with neutropenia for docetaxel in Japanese lung cancer patients cohort

Background

Docetaxel is a widely used cytotoxic agent for treatments of various cancers. The ATP binding cassette (ABC) transporter / multidrug resistance protein (MRP) ABCC10/MRP7, involved in transporting taxanes, has been associated with resistance to these agents. Since genetic variation in drug transporters may affect clinical outcomes, we examined whether polymorphism of ABCC10 could affect clinical responses to docetaxel.

Methods

Using 18 NSCLC cell lines and CRISPR-based genome-edited HeLa cells, we analyzed whether genetic variants of ABCC10 (rs2125739, rs9349256) affected cytotoxicity to docetaxel. Subsequently, we analyzed genetic variants [ABCC10 (rs2125739), ABCB1 (C1236T, C3435T, G2677 T/A), ABCC2 (rs12762549), and SLCO1B3 (rs11045585)] in 69 blood samples of NSCLC patients treated with docetaxel monotherapy. Clinical outcomes were evaluated between genotype groups.

Results

In the cell lines, only one genetic variant (rs2125739) was significantly associated with docetaxel cytotoxicity, and this was confirmed in the genome-edited cell line. In the 69 NSCLC patients, there were no significant differences related to rs2125739 genotype in terms of RR, PFS, or OS. However, this SNP was associated with grade 3/4 neutropenia (T/C group 60% vs. T/T group 87%; P = 0.028). Furthermore, no patient with a T/C genotype experienced febrile neutropenia.

Conclusions

Our results indicate that genetic variation in the ABCC10 gene is associated with neutropenia for docetaxel treatment.

Neutropenia and docetaxel exposure in metastatic castration-resistant prostate cancer patients: A meta-analysis and evaluation of a clinical cohort

The incidence of neutropenia in metastatic castration‐resistant prostate cancer (mCRPC) patients treated with docetaxel has been reported to be lower compared to patients with other solid tumors treated with a similar dose. It is suggested that this is due to increased clearance of docetaxel in mCRPC patients, resulting in decreased exposure. The aims of this study were to (1) determine if exposure in mCRPC patients is lower vs patients with other solid tumors by conducting a meta‐analysis, (2) evaluate the incidence of neutropenia in patients with mCRPC vs other solid tumors in a clinical cohort, and (3) discuss potential clinical consequences. A meta‐analysis was conducted of studies which reported areas under the plasma concentration‐time curves (AUCs) of docetaxel and variability. In addition, grade 3/4 neutropenia was evaluated using logistic regression in a cohort of patients treated with docetaxel. The meta‐analysis included 36 cohorts from 26 trials (n = 1150 patients), and showed that patients with mCRPC had a significantly lower mean AUC vs patients with other solid tumors (fold change [95% confidence interval (CI)]: 1.8 [1.5‐2.2]), with corresponding AUCs of 1.82 and 3.30 mg∙h/L, respectively. Logistic regression, including 812 patient, demonstrated that patients with mCRPC had a 2.2‐fold lower odds of developing grade 3/4 neutropenia compared to patients with other solid tumors (odds ratio [95%CI]: 0.46 [0.31‐0.90]). These findings indicate that mCRPC patients have a lower risk of experiencing severe neutropenia, possibly attributable to lower systemic exposure to docetaxel.

Biodistribution, Safety and Organ Toxicity of Docetaxel-Loaded in HER-2 Aptamer Conjugated Ecoflex® Nanoparticles in a Mouse Xenograft Model of Ovarian Cancer

BACKGROUND

Docetaxel is a notably efficient anticancer drug administered for several types of malignancies including ovarian cancer. However, various side effects caused either by the nonspecific distribution of the active ingredient or by high contents of Tween 80 and ethanol in the currently marketed formulations, could even deprive the patients of the treatment.

OBJECTIVES

In the current study, a novel targeted delivery system composed of Ecoflex® polymeric nanoparticles loaded with docetaxel and equipped with HER-2 specific aptamer molecules was evaluated regarding blood and tissue toxicity, and biodistribution.

METHOD

The tumor-bearing nude mice, achieved by subcutaneous injection of SKOV-3 cells, were divided into four groups treated with normal saline, Taxotere®, targeted docetaxel nanoparticles, and non-targeted docetaxel nanoparticles. Few patents were alos cied in the article.

RESULTS

According to the results of hematologic evaluations, almost all hematologic parameters were in normal range with no significant difference among the four groups. Histopathological studies revealed that treatment with targeted nanoparticles caused a remarkable reduction in mitosis in tumor sections and overall reduced organ toxicity compared with Taxotere®. The only exception was spleen in which more damage was caused by the nanoparticles. The results of the biodistribution study were also in accordance with pathological assessments, with significantly lower drug concentration in non-tumor tissues, except for spleen, when targeted nanoparticles were used compared with Taxotere®.

CONCLUSION

These results could evidence the efficiency of the targeted delivery system in concentrating the drug cargo mostly in its site of action leading to the elimination of its adverse effects caused by exposure of other tissues to the cytotoxic agent.

Pegylated poly(anhydride) nanoparticles for oral delivery of docetaxel

The aim of this work was to investigate the potential of pegylated poly(anhydride) nanoparticles to enhance the oral bioavailability of docetaxel (DTX). Nanoparticles were prepared after the incubation between the copolymer of methyl vinyl ether and maleic anhydride (Gantrez® AN), poly(ethylene glycol) (PEG2000 or PEG6000) and docetaxel (DTX). The oral administration of a single dose of pegylated nanoparticles to mice provided sustained and prolonged therapeutic plasma levels of docetaxel for up 48-72 h. In addition, the relative oral bioavailability of docetaxel was around 32%. The organ distribution studies revealed that docetaxel underwent a similar distribution when orally administered encapsulated in nanoparticles as when intravenously as Taxotere®. This observation, with the fact that the clearance of docetaxel when loaded into the oral pegylated nanoparticles was found to be similar to that of intravenous formulation, suggests that docetaxel would be released at the epithelium surface and then absorbed to the circulation.