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.
Nivolumab treatment is subject to large interpatient variability in both efficacy and toxicity, which may partly be explained by differences in nivolumab exposure. Exposure–response relationships in ...regular healthcare have not been extensively investigated for nivolumab. Therefore, we aimed to identify possible exposure–response relationships in nivolumab-treated patients with non–small-cell lung cancer (NSCLC).
Patients with NSCLC who started second-line nivolumab therapy (3 mg/kg Q2W) between May 5th 2016 and August 1st 2017, and from whom serial blood samples, toxicity data and outcome data were prospectively collected, were included. Follow-up was carried out until November 1st 2017. Patients were classified according to the best overall response (BOR) based on the Response Evaluation Criteria in Solid Tumours, v1.1, and toxicities according to the Common Terminology Criteria for Adverse Events. Nivolumab trough concentrations were measured after 2, 4 and 10 weeks of treatment, excluding dose delays, and calculated geometric means were tested versus BOR or toxicity using analysis of variance and an independent samples t-test, respectively. Overall survival (OS) and progression-free survival were compared between high and low trough concentration groups.
Seventy-six patients were evaluable for analyses. Responders (n = 15) had higher mean trough concentrations than patients with progression (n = 33): 47% higher after 2 weeks (p = 0.001), 53% higher after 4 weeks (p = 0.008) and 73% higher after 10 weeks (p = 0.002). Higher trough concentrations were associated with longer OS (p = 0.001).
This study shows that patients with NSCLC with a response to nivolumab had a higher nivolumab exposure than patients with progression, indicating a potential exposure–response relationship. Further clinical research should focus on clarifying these exposure–response relationships.
•Responders to nivolumab treatment had higher nivolumab exposure than progressors.•No difference in exposure was seen in patients with and without toxicity.•Factors influencing exposure should be clarified in future research.
Treatment with PD-1 inhibitors can be hampered by severe auto-immune-related toxicities. Our objective was to identify single-nucleotide polymorphisms (SNPs) in genes previously associated with ...auto-immunity, which are associated with toxicities in nivolumab-treated NSCLC patients. This was in order to identify patients prone to develop severe toxicities and to gain more insight into the underlying pathobiology.
We analysed 322 nivolumab-treated patients and assessed the association with toxicities for seven SNPs in four genes, which are considered contributors to PD-1-directed T-cell responses, i.e., PDCD1, PTPN11, ZAP70 and IFNG. Every SNP was tested for its association with toxicity endpoints. Significant associations were tested in a validation cohort.
A multivariable analysis in the exploration cohort showed that homozygous variant patients for PDCD1 804C>T (rs2227981) had decreased odds for any grade treatment-related toxicities (n = 96; OR 0.4; 95% CI 0.2-1.0; p = 0.039). However, this result could not be validated (n = 85; OR 0.9; 95% CI 0.4-1.9; p = NS).
Our results show that it is unlikely that the investigated SNPs have a clinical implication in predicting toxicity. A finding, even though negative, that is considered timely and instructive towards further research in biomarker development for checkpoint inhibitor treatments.
Pazopanib is a multi-targeted anticancer tyrosine kinase inhibitor. This study was conducted to develop a population pharmacokinetic (popPK) model describing the complex pharmacokinetics of pazopanib ...in cancer patients.
Pharmacokinetic data were available from 96 patients from three clinical studies. A multi-compartment model including (i) a complex absorption profile, (ii) the potential non-linear dose-concentration relationship and (iii) the potential long-term decrease in exposure was developed.
A two-compartment model best described pazopanib pharmacokinetics. The absorption phase was modelled by two first-order processes: 36 % (relative standard error RSE 34 %) of the administered dose was absorbed with a relatively fast rate (0.4 h
RSE 31 %); after a lag time of 1.0 h (RSE 6 %), the remaining dose was absorbed at a slower rate (0.1 h
RSE 28 %). The relative bioavailability (rF) at a dose of 200 mg was fixed to 1. With an increasing dose, the rF was strongly reduced, which was modelled with an E
(maximum effect) model (E
was fixed to 1, the dose at half of maximum effect was estimated as 480 mg RSE 23 %). Interestingly, the plasma exposure to pazopanib also decreased over time, modelled on rF with a maximum magnitude of 50 % (RSE 27 %) and a first-order decay constant of 0.15 day
(RSE 43 %). The inter-patient and intra-patient variability on rF were estimated as 36 % (RSE 16 %) and 75 % (RSE 22 %), respectively.
A popPK model for pazopanib was developed that illustrated the complex absorption process, the non-linear dose-concentration relationship, the high inter-patient and intra-patient variability, and the first-order decay of pazopanib concentration over time. The developed popPK model can be used in clinical practice to screen covariates and guide therapeutic drug monitoring.
Occurrence of hand-foot syndrome (HFS) during capecitabine treatment often results in treatment interruptions (26 %) or treatment discontinuation (17 %), and can severely decrease quality of life. In ...this study, we investigated whether single nucleotide polymorphisms (SNPs) in genes involved in capecitabine metabolism – other than DPYD – are associated with an increased risk for capecitabine-induced HFS.
Patients treated with capecitabine according to standard of care were enrolled after providing written informed consent for genotyping purposes. Prospectively collected blood samples were used to extract genomic DNA, which was subsequently genotyped for SNPs in CES1, CES2 and CDA. SNPs and clinical baseline factors that were univariably associated with HFS with P ≤ 0.10, were tested in a multivariable model using logistic regression.
Of the 446 patients eligible for analysis, 146 (32.7 %) developed HFS, of whom 77 patients (17.3 %) experienced HFS ≥ grade 2. In the multivariable model, CES1 1165–33 C>A (rs2244613, minor allele frequency 19 %) and CDA 266 + 242 A>G (rs10916825, minor allele frequency 35 %) variant allele carriers were at higher risk of HFS ≥ grade 2 (OR 1.888; 95 %CI 1.075–3.315; P = 0.027 and OR 1.865; 95 %CI 1.087–3.200; P = 0.024, respectively).
We showed that CES1 1165–33 C>A and CDA 266 + 242 A>G are significantly associated with HFS grade 2 and grade 3 in patients treated with capecitabine. Prospective studies should assess whether this increased risk can be mitigated in carriers of these SNPs, when pre-emptive genotyping is being followed by dose adjustment or by alternative treatment by a fluoropyrimidine that is not substrate to CES1, such as S1.
•Over half of patients treated with capecitabine develop hand-foot syndrome.•Hand-foot syndrome often results in treatment interruption or discontinuation.•CES1 1165–33 A and CDA 266 + 242 G carriers are at increased risk of hand-foot syndrome.
Background and Objective
As pazopanib plasma trough concentrations are correlated with treatment outcome, we explored whether single nucleotide polymorphisms in the elimination pathway of pazopanib ...affect systemic pazopanib concentrations.
Methods
The decreased function alleles
CYP3A4 15389 C
>
T (*22)
,
ABCB1 3435 C
>
T
,
ABCG2 421 C
>
A
, and
ABCG2 34G
>
A
were analyzed within a recently developed population-pharmacokinetic model.
Results
Incorporation of
CYP3A4*22
in the model resulted in a 35% lower clearance for variant carriers (0.18 vs. 0.27 L/h; difference in objective function value: − 9.7;
p
< 0.005). Simulated median trough concentrations of cancer patients with
CYP3A4*22
with 600 mg once daily or 800 mg once daily were 31 and 35 mg/L, respectively. The simulated trough concentrations for the population excluding the
CYP3A4*22
carriers after 600 mg once daily or 800 mg once daily were 18 and 20 mg/L, respectively.
Conclusion
This analysis shows that
CYP3A4*22
heterozygotes have a substantial lower pazopanib clearance and that dose adjustments based on
CYP3A4*22
status could be considered.
Abstract
Context
The pathogenesis of tyrosine kinase inhibitor-induced thyroid hormone (TH) alterations are still a matter of debate.
Objective
The objective of this study was to determine the ...effects of sorafenib on TH levels in patients with hepatocellular carcinoma (HCC) and to evaluate possible mechanisms.
Design
We performed a prospective cohort study between 2009 and 2016.
Setting
This study was conducted at a tertiary referral center.
Patients
This study included 57 consecutive patients with HCC who were treated with sorafenib.
Main Outcome Measure
Thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels were measured every 6 weeks, and extensive thyroid function tests (TFTs) were measured before treatment (t0), after 6 weeks (t6), and at the end of therapy. The effect of sorafenib on TH transport by monocarboxylate transporter (MCT)8 or MCT10 was tested in transfected COS1 cells.
Results
Four patients (7%) developed thyroiditis. Among the other patients, 30% had elevation of TSH or FT4 above the normal range. Overall, between t0 and t6, mean TSH increased from 1.28 to 1.57 mU/L (P < 0.001) and mean FT4 from 18.4 to 21.2 pmol/L (P < 0.001). Simultaneously, the serum triiodothyronine (T3)/reverse triiodothyronine ratio and the (T3/thyroxine) ×100 ratio decreased. Sorafenib decreased cellular T3 uptake by MCT8 and to a lesser extent by MCT10.
Conclusions
These in vivo data suggest that sorafenib affects TFTs on multiple levels. Our in vitro experiments suggest a possible role of sorafenib-induced inhibition of T3 transport into the cell by MCT8 and MCT10.
Sorafenib-induced changes in thyroid function tests are mediated at several levels in vivo. In vitro experiments show inhibition of T3 transport into the cell by MCT8 and MCT10.
BackgroundA minority of patients with advanced non-small-cell lung cancer (NSCLC) benefit from treatment with immune checkpoint inhibitors (ICIs). Ineffective effector function of activated T and NK ...cells may lead to reduced tumor cell death, even when these activated effector cells are released from their immune checkpoint brake. Hence, in this study we aimed to assess the association of baseline serum granzyme B, as well as germline variation of the GZMB gene, with clinical outcome to programmed cell death protein 1 (PD-1) blockade.MethodsA total of 347 patients with stage IV NSCLC who started nivolumab treatment between June 2013 and June 2017 were prospectively included. Baseline serum and whole blood was available, allowing for protein quantification and targeted DNA sequencing. Clinical outcome was based on best overall response (BOR) according to Response Evaluation Criteria in Solid Tumors, V.1.1, progression-free survival (PFS), and overall survival (OS).ResultsPatients with low serum levels of granzyme B had worse PFS (HR: 1.96; 95% CI: 1.12 to 3.43; p=0.018) and worse OS (HR: 2.08; 95% CI: 1.12 to 3.87; p=0.021) than patients with high baseline serum levels. To validate the findings, germline variation of GZMB rs8192917 was assessed. Patients with homozygous and heterozygous variants of GZMB rs8192917 had worse BOR (OR: 1.60; 95% CI: 1.01 to 2.52; p=0.044) and worse PFS (HR: 1.38; 95% CI:1.02 to 1.87; p=0.036) than wild types.ConclusionsA low baseline serum level of granzyme B and germline variation of GZMB was associated with worse clinical outcome in NSCLC, emphasizing the relevance and additional value of monitoring germline genetic variations which mirror cytotoxic functions of T cells in ICI therapy.Trail registration numberDutch Trial Registry (NL6828).
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