Irinotecan-Induced Toxicity:A Pharmacogenetic Study Beyond UGT1A1

Background and objective: Side effects of irinotecan treatment can be dose limiting and may impair quality of life. In this study, we investigated the correlation between single nucleotide polymorphisms (SNPs) in genes encoding enzymes involved in the irinotecan metabolism and transport, outside UGT1A1, and irinotecan-related toxicity. We focused on carboxylesterases, which are involved in formation of the active metabolite SN-38 and on drug transporters. Methods: Patients who provided written informed consent at the Erasmus Medical Center Cancer Institute to the Code Geno study (local protocol: MEC02-1002) or the IRI28-study (NTR-6612) were enrolled in the study and were genotyped for 15 SNPs in the genes CES1, CES2, SLCO1B1, ABCB1, ABCC2, and ABCG2. Results: From 299 evaluable patients, 86 patients (28.8%) developed severe irinotecan-related toxicity. A significantly higher risk of toxicity was seen in ABCG2 c.421C&gt;A variant allele carriers (P = 0.030, OR 1.88, 95% CI 1.06–3.34). Higher age was associated with all grade diarrhea (P = 0.041, OR 1.03, 95% CI 1.00–1.06). In addition, CES1 c.1165-41C&gt;T and CES1 n.95346T&gt;C variant allele carriers had a lower risk of all-grade thrombocytopenia (P = 0.024, OR 0.42, 95% CI 0.20–0.90 and P = 0.018, OR 0.23, 95% CI 0.08–0.79, respectively). Conclusion: Our study indicates that ABCG2 and CES1 SNPs might be used as predictive markers for irinotecan-induced toxicity.</p

Influence of enzalutamide on cabazitaxel pharmacokinetics: A Drug–Drug interaction study in metastatic castration-resistant prostate cancer (mCRPC) patients

Purpose: In ongoing clinical research on metastatic castration-resistant prostate cancer (mCRPC) treatment, the potential enhanced efficacy of the combination of taxanes with AR-targeted agents, that is, enzalutamide and abiraterone, is currently being explored. Because enzalutamide induces the CYP3A4 enzyme and taxanes are metabolized by this enzyme, a potential drug–drug interaction needs to be investigated. Experimental Design: Therefore, we performed a pharmacokinetic cross-over study in mCRPC patients who were scheduled for treatment with cabazitaxel Q3W (25 mg/m2). Patients were studied for three consecutive cabazitaxel cycles. Enzalutamide (160 mg once daily) was administered concomitantly after the first cabazitaxel cycle, during 6 weeks. Primary endpoint was the difference in mean area under the curve (AUC) between the first (cabazitaxel monotherapy) and third cabazitaxel cycle, when enzalutamide was added. Results: A potential clinically relevant 22% (95% CI, 9%–34%; P ¼ 0.005) reduction in cabazitaxel exposure was found with concomitant enzalutamide use. The geometric mean AUC0–24h of cabazitaxel was 181 ngh/mL (95% CI, 150–219 ngh/mL) in cycle 3 and 234 ngh/mL (95% CI, 209–261 ngh/mL) in cycle 1. This combination did not result in excessive toxicity, whereas PSA response was promising. Conclusions: We found a significant decrease in cabazitaxel exposure when combined with enzalutamide. In an era of clinical trials on combination strategies for mCRPC, it is important to be aware of clinically relevant drug–drug interactions. Because recent study results support the use of a lower standard cabazitaxel dose of 20 mg/m2, the clinical relevance of this interaction may be substantial, because the addition of enzalutamide may result in subtherapeutic cabazitaxel exposure

The SAFE-trial:Safe surgery for glioblastoma multiforme: Awake craniotomy versus surgery under general anesthesia. Study. protocol for a multicenter prospective randomized controlled trial

Background: Surgery of GBM nowadays is usually performed under general anesthesia (GA) and resections are often not as aggressive as possible, due to the chance of seriously damaging the patient with a rather low life expectancy. A surgical technique optimizing resection of the tumor in eloquent areas but preventing neurological deficits is necessary to improve survival and quality of life in these patients. Awake craniotomy (AC) with the use of cortical and subcortical stimulation has been widely implemented for low-grade glioma resections (LGG), but not yet for GBM. AC has shown to increase resection percentage and preserve quality of life in LGG and could thus be of important value in GBM surgery. Methods/design: This study is a prospective, multicenter, randomized controlled trial (RCT). Consecutive patients with a glioblastoma in or near eloquent areas (Sawaya grading II/III) will be 1:1 randomized to awake craniotomy or craniotomy under general anesthesia. 246 patients will be included in neurosurgical centers in the Netherlands and Belgium. Primary end-points are: 1) Postoperative neurological morbidity and 2) Proportion of patients with gross-total resections. Secondary end-points are: 1) Health-related quality of life; 2) Progression-free survival (PFS); 3) Overall survival (OS) and 4) Frequency and severity of Serious Adverse Effects in each group. Also, a cost-benefit analysis will be performed. All patients will receive standard adjuvant treatment with concomitant chemoradiotherapy. Discussion: This RCT should demonstrate whether AC is superior to craniotomy under GA on neurological morbidity, extent of resection and survival for glioblastoma resections in or near eloquent areas. Trial registration: Clinicaltrials.gov: NCT03861299 Netherlands Trial Register (NTR): NL758

Realizing better doctor-patient dialogue about choices in palliative care and early phase clinical trial participation: towards an online value clarification tool (OnVaCT)

Background: Patients with advanced cancer for whom standard systemic treatment is no longer available may be offered participation in early phase clinical trials. In the decision making process, both medical-technical information and patient values and preferences are important. Since patients report decisional conflict after deciding on participation in these trials, improving the decision making process is essential. We aim to develop and evaluate an Online Value Clarification Tool (OnVaCT) to assist patients in clarifying their values around this end-of-life decision. This improved sharing of values is hypothesized to support medical oncologists in tailoring their information to individual patients’ needs and, consequently, to support patients in taking decisions in line with their values and reduce decisional conflict. Methods: In the first part, patients’ values and preferences and medical oncologists’ views hereupon will be explored in interviews and focus groups to build a first prototype OnVaCT using digital communication (serious gaming). Next, we will test feasibility during think aloud sessions, to deliver a ready-to-implement OnVaCT. In the second part, the OnVaCT, with accompanied training module, will be evaluated in a pre-test (12–18 months before implementation) post-test (12–18 months after implementation) study in three major Dutch cancer centres. We will include 276 patients (> 18 years) with advanced cancer for whom standard systemic therapy is no longer available, and who are referred for participation in early phase clinical trials. The first consultation will be recorded to analyse patient-physician communication regarding the discussion of patients’ values and the decision making process. Three weeks afterwards, decisional conflict will be measured. Discussion: This project aims to support the discussion of patient values when considering participation in early phase clinical trials. By including patients before their first appointment with the medical oncologist and record

The influence of single-nucleotide polymorphisms on overall survival and toxicity in cabazitaxel-treated patients with metastatic castration-resistant prostate cancer

Purpose: Cabazitaxel, used in patients with metastatic castration-resistant prostate cancer (mCRPC), is associated with adverse events which may require dose reductions or discontinuation of treatment. We investigated the potential association of single-nucleotide polymorphisms (SNPs) in genes encoding drug transporters and drug-metabolizing enzymes with cabazitaxel toxicity, overall survival (OS) and pharmacokinetics (PK). Methods: A total of 128 cabazitaxel-treated mCRPC patients, of whom prospectively collected data on toxicity and OS were available and 24 mCRPC patients with available cabazitaxel PK measurements, were genotyped using genomic DNA obtained from EDTA blood. The SLCO1B1 (388A > G; *1B; rs2306283 and 521 T > C; *5; rs4149056 and haplotype SLCO1B1*15), SLCO1B3 (334 T > G; rs4149117), CYP3A4 (*22; rs35599367), CYP3A5 (*3; rs776746), ABCB1 (3435C > T; rs1045642), and TUBB1 (57 + 87A > C; rs463312) SNPs were tested for their association with clinical and PK parameters by univariate/multivariate logistic regression, log-rank test, or Kruskal–Wallis test. Results: The SLCO1B1*15 haplotype was significantly associated with a lower incidence of leukopenia and neutropenia (p = 0.020 and p = 0.028, respectively). Patients harboring a homozygous variant for SLCO1B1*1B experienced higher rate ≥ grade 3 (p = 0.042). None of the SNPs were associated with pharmacokinetics or OS. Conclusions: In this study, SLCO1B1 (SLCO1B1*15 and SLCO1B1*1B) was associated with cabazitaxel-induced adverse events in mCRPC patients. As the associations were opposite to previous studies in other drugs and contradicted an underlying pharmacokinetic rationale, these findings are likely to be false-positive and would ideally be validated with even larger (pharmacokinetic) cohorts

Decisional Conflict after Deciding on Potential Participation in Early Phase Clinical Cancer Trials:Dependent on Global Health Status, Satisfaction with Communication, and Timing

SIMPLE SUMMARY: Early phase clinical trials are an essential part of modern drug development and thus the advance of anti-cancer therapies for patients. However, deciding whether to participate in such trials can be complex and patients have reported decisional conflict (i.e., unresolved decisional needs). The aim of our study was to untangle several factors that contribute to decisional conflict in patients with advanced cancer who have recently been asked to decide whether to participate in early phase clinical trials. We found that patients experienced less decisional conflict if they had a better global health status, higher satisfaction, and made their decision sooner. Other factors, such as the decision to (not) participate, did not prove to be the best indicators for decisional conflict. With these insights, we can start to build hypotheses on how to improve the decision-making process for patients with end-stage cancer, which can ultimately improve their quality of life. ABSTRACT: When standard treatment options are not available anymore, patients with advanced cancer may participate in early phase clinical trials. Improving this complex decision-making process may improve their quality of life. Therefore, this prospective multicenter study with questionnaires untangles several contributing factors to decisional conflict (which reflects the quality of decision-making) in patients with advanced cancer who recently decided upon early phase clinical trial participation (phase I or I/II). We hypothesized that health-related quality of life, health literacy, sense of hope, satisfaction with the consultation, timing of the decision, and the decision explain decisional conflict. Mean decisional conflict in 116 patients was 30.0 (SD = 16.9). Multivariate regression analysis showed that less decisional conflict was reported by patients with better global health status (β = −0.185, p = 0.018), higher satisfaction (β = −0.246, p = 0.002), and who made the decision before (β = −0.543, p < 0.001) or within a week after the consultation (β = −0.427, p < 0.001). These variables explained 37% of the variance in decisional conflict. Healthcare professionals should realize that patients with lower global health status and who need more time to decide may require additional support. Although altering such patient intrinsic characteristics is difficult, oncologists can impact the satisfaction with the consultation. Future research should verify whether effective patient-centered communication could prevent decisional conflict

Feasibility of extrapolating randomly taken plasma samples to trough levels for therapeutic drug monitoring purposes of small molecule kinase inhibitors

Small molecule kinase inhibitors (SMKIs) are widely used in oncology. Therapeutic drug monitoring (TDM) for SMKIs could reduce underexposure or overexposure. However, logistical issues such as timing of blood withdrawals hamper its implementation into clinical practice. Extrapolating a random concentration to a trough concentration using the elimination half-life could be a simple and easy way to overcome this problem. In our study plasma concentrations observed during 24 h blood sampling were used for extrapolation to trough levels. The objective was to demonstrate that extrapolation of randomly taken blood samples will lead to equivalent estimated trough samples compared to measured Cmin values. In total 2241 blood samples were analyzed. The estimated Ctrough levels of afatinib and sunitinib fulfilled the equivalence criteria if the samples were drawn after Tmax . The calculated Ctrough levels of erlotinib, imatinib and sorafenib met the equivalence criteria if they were taken, respectively, 12 h, 3 h and 10 h after drug intake. For regorafenib extrapolation was not feasible. In conclusion, extrapolation of randomly taken drug concentrations to a trough concentration using the mean elimination half-life is feasible for multiple SMKIs. Therefore, this simple method could positively contribute to the implementation of TDM in oncology

Influence of genetic variation in COMT on cisplatin-induced nephrotoxicity in cancer patients

Cisplatin is a chemotherapeutic agent widely used for multiple indications. Unfortunately, in a substantial set of patients treated with cisplatin, dose-limiting acute kidney injury (AKI) occurs. Here, we assessed the association of 3 catechol-O-methyltransferase (COMT) single nucleotide polymorphisms (SNPs) with increased cisplatin-induced nephrotoxicity. In total, 551 patients were genotyped for the 1947 G>A (Val158Met, rs4680), c.615 + 310 C>T (rs4646316), and c.616 – 367 C>T (rs9332377) polymorphisms. Associations between these variants and AKI grade ≥3 were studied. The presence of a homozygous variant of c.616-367C>T was associated with a decreased occurrence of AKI grade 3 toxicity (p = 0.014, odds ratio (OR) 0.201, 95% confidence interval (CI) (0.047–0.861)). However, we could not exclude the role of dehydration as a potential cause of AKI in 25 of the 27 patients with AKI grade 3, which potentially affected the results substantially. As a result of the low incidence of AKI grade 3 in this dataset, the lack of patients with a COMT variant, and the high number of patients with dehydration, the association between COMT variants and AKI does not seem clinically relevant

The Risk of QTc-Interval Prolongation in Breast Cancer Patients Treated with Tamoxifen in Combination with Serotonin Reuptake Inhibitors

Purpose: Antidepressants like the serotonin reuptake inhibitors (SRIs) are often used concomitantly with tamoxifen (e.g. for treatment of depression). This may lead to an additional prolongation of the QTc-interval, with an increased risk of cardiac side effects. Therefore we investigated whether there is a drug-drug interaction between tamoxifen and SRIs resulting in a prolonged QTc-interval. Methods: Electrocardiograms (ECGs) of 100 patients were collected at steady state tamoxifen treatment, with or without concomitant SRI co-medication. QTc-interval was manually measured and calculated using the Fridericia formula. Primary outcome was difference in QTc-interval between tamoxifen monotherapy and tamoxifen concomitantly with an SRI. Results: The mean QTc-interval was 12.4 ms longer when tamoxifen was given concomitantly with an SRI (95% CI:1.8–23.1 ms; P = 0.023). Prolongation of the QTc-interval was particularly pronounced for paroxetine (17.2 ms; 95%CI:1.4–33.0 ms; P = 0.04), escitalopram (12.5 ms; 95%CI:4.4–20.6 ms; P 500 ms. Conclusions: Concomitant use of tamoxifen and SRIs resulted in a significantly higher mean QTc-interval, which was especially the case for paroxetine, escitalopram and citalopram. When concomitant administration with an SRI is warranted venlafaxine is preferred