Since its clinical introduction in 1998, the topoisomerase I inhibitor irinotecan has been widely used in the treatment of solid tumors, including colorectal, pancreatic, and lung cancer. Irinotecan ...therapy is characterized by several dose-limiting toxicities and large interindividual pharmacokinetic variability. Irinotecan has a highly complex metabolism, including hydrolyzation by carboxylesterases to its active metabolite SN-38, which is 100- to 1000-fold more active compared with irinotecan itself. Several phase I and II enzymes, including cytochrome P450 (CYP) 3A4 and uridine diphosphate glucuronosyltransferase (UGT) 1A, are involved in the formation of inactive metabolites, making its metabolism prone to environmental and genetic influences. Genetic variants in the DNA of these enzymes and transporters could predict a part of the drug-related toxicity and efficacy of treatment, which has been shown in retrospective and prospective trials and meta-analyses. Patient characteristics, lifestyle and comedication also influence irinotecan pharmacokinetics. Other factors, including dietary restriction, are currently being studied. Meanwhile, a more tailored approach to prevent excessive toxicity and optimize efficacy is warranted. This review provides an updated overview on today’s literature on irinotecan pharmacokinetics, pharmacodynamics, and pharmacogenetics.
Although therapeutic drug monitoring (TDM) is an important tool in guiding drug dosing for other areas of medicine including infectious diseases, cardiology, psychiatry and transplant medicine, it ...has not gained wide acceptance in oncology. For imatinib and other tyrosine kinase inhibitors, a flat dosing approach is utilised for management of oral chemotherapy. There are many published studies examining the correlation of blood concentrations with clinical effects of imatinib. The International Association of Therapeutic Drug Monitoring and Clinical Toxicology (IATDMCT) determined that there was a need to examine the published literature regarding utility of TDM in imatinib therapy and to develop consensus guidelines for TDM based on the available data. This article summarises the scientific evidence regarding TDM of imatinib, as well as the consensus guidelines developed by the IATDMCT.
•Imatinib is typically administered to patients in a flat rate dosing paradigm.•Many studies suggest monitoring imatinib blood concentrations optimises treatment.•The IATDMCT Oncology Committee has developed consensus guidelines for imatinib TDM.•The scientific evidence and consensus guidelines are summarised here.
Identification of the optimal dose remains a key challenge in drug development. For cytotoxic drugs, the standard approach is based on identifying the maximum tolerated dose (MTD) in phase I trials ...and incorporating this to subsequent trials. However, this strategy does not take into account important aspects of clinical pharmacology. For targeted agents, the dose-effect relationships from preclinical studies are less obvious, and it is important to change the way these agents are developed to avoid recommending drug doses for different populations without evidence of differential antitumour effects in different diseases. The use of expanded cohorts in phase I trials to better define MTD and refine dose optimization should be further explored together with a focus on efficacy rather than toxicity-based predictions. Another key consideration in dose optimization is related to interindividual pharmacokinetic variability. High variability in intra-individual pharmacokinetics has been observed for many orally-administered drugs, especially those with low bioavailability, which might complicate identification of dose-effect relationships. End-organ dysfunction, interactions with other prescription drugs, herbal supplements, adherence, and food intake can influence pharmacokinetics. It is important these variables are identified during early clinical trials and considered in the development of further phase II and subsequent large-scale phase III studies.
Abstract Background Androgen receptor splice variant 7 ( AR-V7 ) in circulating tumor cells (CTCs) from patients with metastatic castration-resistant prostate cancer (mCRPC) was recently demonstrated ...to be associated with resistance to abiraterone and enzalutamide. Cabazitaxel might, however, remain effective in AR-V7 -positive patients. Objective To investigate the association between AR-V7 expression in CTCs and resistance to cabazitaxel. Design, setting, and participants We selected patients with mCRPC from the multicenter, randomized, phase 2, randomized, open-label, multicenter study in mCRPC on the pharmacodynamic effects of budesonide on cabazitaxel (Jevtana) (CABARESC). Before the start of the first and third cabazitaxel cycle, CTCs were enumerated using the CellSearch System. In patients with ≥10 CTCs in 7.5 ml blood at baseline, the expression of AR-V7 was assessed by quantitative polymerase chain reaction. Outcome measures and statistical analysis The primary end point was the association between the AR-V7 status and the CTC response rate (decrease to fewer than five CTCs in 7.5 ml blood during treatment). Secondary end points were the prostate-specific antigen (PSA) response rate (RR) and overall survival (OS). Analyses were performed using chi-square and log-rank tests. Results and limitations AR-V7 was detected in 16 of 29 patients (55%) with ≥10 CTCs and was more frequently found in abiraterone pretreated patients (5 of 5 100% treated vs 7 of 20 35% untreated; p = 0.009). We found no differences in CTC and PSA RRs. The presence of AR-V7 in CTCs was not associated with progression-free survival (hazard ratio HR: 0.8; 95% confidence interval CI, 0.4–1.8) or overall survival (HR 1.6; 95% CI, 0.6–4.4). Conclusions The response to cabazitaxel seems to be independent of the AR-V7 status of CTCs from mCRPC patients. Consequently, cabazitaxel might be a valid treatment option for patients with AR-V7 -positive CTCs. Patient summary Tools are needed to select specific treatments for specific patients at specific times. The presence of the gene AR-V7 in CTCs has been associated with resistance to anti-androgen receptor treatments. We investigated whether this holds true for cabazitaxel, but we found cabazitaxel to be effective independent of the presence of AR-V7.
Summary Background The poly(ADP-ribose) polymerase inhibitor olaparib has shown antitumour activity in patients with platinum-sensitive, recurrent, high-grade serous ovarian cancer with or without ...BRCA1 or BRCA2 mutations. The aim of this study was to assess the efficacy and tolerability of olaparib in combination with chemotherapy, followed by olaparib maintenance monotherapy, versus chemotherapy alone in patients with platinum-sensitive, recurrent, high-grade serous ovarian cancer. Methods In this randomised, open-label, phase 2 study, adult patients with platinum-sensitive, recurrent, high-grade serous ovarian cancer who had received up to three previous courses of platinum-based chemotherapy and who were progression free for at least 6 months before randomisation received either olaparib (200 mg capsules twice daily, administered orally on days 1–10 of each 21-day cycle) plus paclitaxel (175 mg/m2 , administered intravenously on day 1) and carboplatin (area under the curve AUC 4 mg/mL per min, according to the Calvert formula, administered intravenously on day 1), then olaparib monotherapy (400 mg capsules twice daily, given continuously) until progression (the olaparib plus chemotherapy group), or paclitaxel (175 mg/m2 on day 1) and carboplatin (AUC 6 mg/mL per min on day 1) then no further treatment (the chemotherapy alone group). Randomisation was done by an interactive voice response system, stratified by number of previous platinum-containing regimens received and time to disease progression after the previous platinum regimen. The primary endpoint was progression-free survival according to Response Evaluation Criteria in Solid Tumors version 1.1, analysed by intention to treat. Prespecified exploratory analyses included efficacy by BRCA mutation status, assessed retrospectively. This study is registered with ClinicalTrials.gov , number NCT01081951 , and has been completed. Findings Between Feb 12 and July 30, 2010, 173 patients at 43 investigational sites in 12 countries were enrolled into the study, of whom 162 were eligible and were randomly assigned to the two treatment groups (81 to the olaparib plus chemotherapy group and 81 to the chemotherapy alone group). Of these randomised patients, 156 were treated in the combination phase (81 in the olaparib plus chemotherapy group and 75 in the chemotherapy alone group) and 121 continued to the maintenance or no further treatment phase (66 in the olaparib plus chemotherapy group and 55 in the chemotherapy alone group). BRCA mutation status was known for 107 patients (either at baseline or determined retrospectively): 41 (38%) of 107 had a BRCA mutation (20 in the olaparib plus chemotherapy group and 21 in the chemotherapy alone group). Progression-free survival was significantly longer in the olaparib plus chemotherapy group (median 12·2 months 95% CI 9·7–15·0) than in the chemotherapy alone group (median 9·6 months 95% CI 9·1–9·7) (HR 0·51 95% CI 0·34–0·77; p=0·0012), especially in patients with BRCA mutations (HR 0·21 0·08–0·55; p=0·0015). In the combination phase, adverse events that were reported at least 10% more frequently with olaparib plus chemotherapy than with chemotherapy alone were alopecia (60 74% of 81 vs 44 59% of 75), nausea (56 69% vs 43 57%), neutropenia (40 49% vs 29 39%), diarrhoea (34 42% vs 20 27%), headache (27 33% vs seven 9%), peripheral neuropathy (25 31% vs 14 19%), and dyspepsia (21 26% vs 9 12%); most were of mild-to-moderate intensity. The most common grade 3 or higher adverse events during the combination phase were neutropenia (in 35 43% of 81 patients in the olaparib plus chemotherapy group vs 26 35% of 75 in the chemotherapy alone group) and anaemia (seven 9% vs five 7%). Serious adverse events were reported in 12 (15%) of 81 patients in the olaparib plus chemotherapy group and 16 of 75 (21%) patients in the chemotherapy alone group. Interpretation Olaparib plus paclitaxel and carboplatin followed by maintenance monotherapy significantly improved progression-free survival versus paclitaxel plus carboplatin alone, with the greatest clinical benefit in BRCA -mutated patients, and had an acceptable and manageable tolerability profile. Funding AstraZeneca.
Summary In the past decade, many tyrosine-kinase inhibitors have been introduced in oncology and haemato-oncology. Because this new class of drugs is extensively used, serious drug–drug interactions ...are an increasing risk. In this Review, we give a comprehensive overview of known or suspected drug–drug interactions between tyrosine-kinase inhibitors and other drugs. We discuss all haemato-oncological and oncological tyrosine-kinase inhibitors that had been approved by Aug 1, 2013, by the US Food and Drug Administration or the European Medicines Agency. Various clinically relevant drug interactions with tyrosine-kinase inhibitors have been identified. Most interactions concern altered bioavailability due to altered stomach pH, metabolism by cytochrome P450 isoenzymes, and prolongation of the QTc interval. To guarantee the safe use of tyrosine-kinase inhibitors, a drugs review for each patient is needed. This Review provides specific recommendations to guide haemato-oncologists, oncologists, and clinical pharmacists, through the process of managing drug–drug interactions during treatment with tyrosine-kinase inhibitors in daily clinical practice.
Conventional taxanes are used as cornerstone of the chemotherapeutical treatment for a variety of malignancies. Nevertheless, a large proportion of patients do not benefit from their treatment while ...they do suffer from severe adverse events related to the solvent or to the active compound. Cremophor EL and polysorbate 80 free formulations, conjugates, oral formulations and different types of drug delivery systems are some examples of the several attempts to improve the treatment with taxanes. In this review article, we discuss recent clinical developments of nanomediated drug delivery systems of taxanes for the treatment of cancer. Targeting mechanisms of drug delivery systems and characteristics of the most commonly used taxane-containing drug delivery systems in the clinical setting will be discussed in this review.
The cyclin-dependent kinase (CDK) 4/6 inhibitors belong to a new class of drugs that interrupt proliferation of malignant cells by inhibiting progression through the cell cycle. Three such ...inhibitors, palbociclib, ribociclib, and abemaciclib were recently approved for breast cancer treatment in various settings and combination regimens. On the basis of their impressive efficacy, all three CDK4/6 inhibitors now play an important role in the treatment of patients with HR+, HER2− breast cancer; however, their optimal use still needs to be established. The three drugs have many similarities in both pharmacokinetics and pharmacodynamics. However, there are some differences on the basis of which the choice for a particular CDK4/6 inhibitor for an individual patient can be important. In this article, the clinical pharmacokinetic and pharmacodynamic profiles of the three CDK4/6 inhibitors are reviewed and important future directions of the clinical applicability of CDK4/6 inhibitors will be discussed.
Objectives
A minority of NSCLC patients benefit from anti-PD1 immune checkpoint inhibitors. A rational combination of biomarkers is needed. The objective was to determine the predictive value of ...tumor mutational load (TML), CD8
+
T cell infiltration, HLA class-I and PD-L1 expression in the tumor.
Materials and methods
Metastatic NSCLC patients were prospectively included in an immune-monitoring trial (NTR7015) between April 2016-August 2017, retrospectively analyzed in FFPE tissue for TML (NGS: 409 cancer-related-genes) and by IHC staining to score PD-L1, CD8
+
T cell infiltration, HLA class-I. PFS (RECISTv1.1) and OS were analyzed by Kaplan–Meier methodology.
Results
30 patients with adenocarcinoma (67%) or squamous cell carcinoma (33%) were included. High TML was associated with better PFS (
p
= 0.004) and OS (
p
= 0.025). Interaction analyses revealed that patients with both high TML and high total CD8
+
T cell infiltrate (
p
= 0.023) or no loss of HLA class-I (
p
= 0.026), patients with high total CD8
+
T cell infiltrate and no loss of HLA class-I (
p
= 0.041) or patients with both high PD-L1 and high TML (
p
= 0.003) or no loss of HLA class-I (
p
= 0.032) were significantly associated with better PFS. Unsupervised cluster analysis based on these markers revealed three sub-clusters, of which cluster-1A was overrepresented by patients with progressive disease (15 out of 16), with significant effect on PFS (
p
= 0.007).
Conclusion
This proof-of-concept study suggests that a combination of PD-L1 expression, TML, CD8
+
T cell infiltration and HLA class-I functions as a better predictive biomarker for response to anti-PD-1 immunotherapy. Consequently, refinement of this set of biomarkers and validation in a larger set of patients is warranted.
Highlights • CYP2D6 genotyping is an oversimplified approach for tamoxifen individualization. • Tamoxifen pharmacokinetics are influenced by many genetic and environmental factors. • There is ...increasing evidence supporting the important role of endoxifen. • TDM is likely to be the optimal strategy for tamoxifen individualization. • Phenotyping strategies may be useful in determining the initial tamoxifen dose.
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