Efficacy and Toxicity of Weekly Carboplatin and Paclitaxel as Induction or Palliative Treatment in Advanced Esophageal Cancer Patients

Many patients have advanced esophageal cancer at diagnosis. However, the most optimal treatment has not been identified. Therefore, we evaluated a weekly regimen of carboplatin (area under the curve (AUC)) of 4 and paclitaxel at 100 mg/m2 as an induction or palliative treatment. All patients with advanced (gastro)esophageal cancer treated with this regimen between 2002–2018 were included. Exclusion cr

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

Feasibility of therapeutic drug monitoring of sorafenib in patients with liver or thyroid cancer

Introduction: Sorafenib is a tyrosine-kinase inhibitor approved for the treatment of renal cell carcinoma, hepatocellular carcinoma, thyroid carcinoma, and desmoid fibromatosis. As high inter-individual variability exists in exposure, there is a scientific rationale to pursue therapeutic drug monitoring (TDM). We investigated the feasibility of TDM in patients on sorafenib and tried to identify sub-groups in whom pharmacokinetically (PK) guided-dosing might be of added value. Methods: We included patients who started on sorafenib (between October 2017 and June 2020) at the recommended dose of 400 mg BID or with a step-up dosing schedule. Plasma trough levels (Ctrough) were measured at pre-specified time-points. Increasing the dose was advised if Ctrough was below the target of 3750 ng/mL and toxicity was manageable. Results: A total of 150 samples from 36 patients were collected. Thirty patients (83 %) had a Ctrough below the prespecified target concentration at a certain time point during treatment. Toxicity from sorafenib hampered dosing according to target Ctrough in almost half of the patients. In 11 patients, dosing was adjusted based on Ctrough. In three patients, this resulted in an adequate Ctrough without additional toxicity four weeks after the dose increase. In the remaining eight patients, dose adjustment based on Ctrough did not result in a Ctrough above the target or caused excessive toxicity. Conclusions: TDM for sorafenib is not of added value in daily clinical practice. In most cases, toxicity restricts the possibility of dose escalations.</p

The added value of H-2 antagonists in premedication regimens during paclitaxel treatment

BACKGROUND: Ranitidine, a histamine 2 blocker, is the standard of care to prevent hypersensitivity reactions (HSRs) caused by paclitaxel infusion. However, the added value of ranitidine in this premedication regimen is controversial. Therefore, we compared the incidence of HSRs during paclitaxel treatment between a standard regimen including ranitidine and a regimen without ranitidine. METHODS: This prospective, pre-post interventional, non-inferiority study compared the standard premedication regimen (N = 183) with dexamethasone, clemastine and ranitidine with a premedication regimen without ranitidine (N = 183). The primary outcome was the incidence of HSR grade >= 3. Non-inferiority was determined by checking whether the upper bound of the twosided 90% confidence interval (CI) for the difference in HSR rates excluded the +6% non-inferiority margin. RESULTS: In both the pre-intervention (with ranitidine) and post-intervention (without ranitidine) group 183 patients were included. The incidence of HSR grade >= 3 was 4.4% (N = 8) in the pre-intervention group and 1.6% (N = 3) in the post-intervention group: difference -2.7% (90% CI: -6.2 to 0.1). CONCLUSIONS: As the upper boundary of the 90% CI does not exceed the predefined non-inferiority margin of +6%, it can be concluded that a premedication regimen without ranitidine is non-inferior to a premedication regimen with ranitidine

Influence of probenecid on the pharmacokinetics and pharmacodynamics of sorafenib

Prior studies have demonstrated an organic anion transporter 6 (OAT6)-mediated accumulation of sorafenib in keratinocytes. The OAT6 inhibitor probenecid decreases sorafenib uptake in skin and might, therefore, decrease sorafenib-induced cutaneous adverse events. Here, the influence of probenecid on sorafenib pharmacokinetics and toxicity was investigated. Pharmacokinetic sampling was performed in 16 patients on steady-state sorafenib treatment at days 1 and 15 of the study. Patients received sorafenib (200–800 mg daily) in combination with probenecid (500 mg two times daily (b.i.d.)) on days 2–15. This study was designed to determine bioequivalence with geometric mean Area under the curve from zero to twelve hours (AUC0–12 h) as primary endpoint. During concomitant probenecid, s

Influence of OATP1B1 Function on the Disposition of Sorafenib-β-D-Glucuronide

The oral multikinase inhibitor sorafenib undergoes extensive UGT1A9-mediated formation of sorafenib-β-D-glucuronide (SG). Using transporter-deficient mouse models, it was previously established that SG can be extruded into bile by ABCC2 or follow a liver-to-blood shuttling loop via ABCC3-mediated efflux into the systemic circulation, and subsequent uptake in neighboring hepatocytes by OATP1B-type transporters. Here we evaluated the possibility that this unusual process, called hepatocyte hopping, is also operational in humans and can be modulated through pharmacological inhibition. We found that SG transport by OATP1B1 or murine Oatp1b2 was effectively inhibited by rifampin, and that this agent can significantly increase plasma levels of SG in wildtype mice, but not in Oatp1b2-deficient animals. In human subjects receiving sorafenib, rifampin acutely increased the systemic exposure to SG. Our study emphasizes the need to consider hepatic handling of xenobiotic glucuronides in the design of drug-drug interaction studies of agents that undergo extensive phase II conjugation

The influence of body composition on the systemic exposure of paclitaxel in esophageal cancer patients

Changes in body composition are associated with chemotherapy-related toxicities and effectiveness of treatment. It is hypothesized that the pharmacokinetics (PK) of chemotherapeutics may depend on body composition. The effects of body composition on the variability of paclitaxel PK were studied in patients with esophageal cancer. Skeletal muscle index (SMI), visceral adipose tissue (VAT), and skeletal muscle density (SMD) were measured at the third lumbar vertebra on computed tomography (CT) scans performed before treatment. Paclitaxel PK data were collected from a prospective study performed between May 2004 and January 2014. Non-linear mixed-effects modeling was used to fit paclitaxel PK profiles and evaluate the covariates body surface area (BSA), SMI, VAT, and SMD using a significance threshold of p < 0.001. Paclitaxel was administered to 184 patients in a dose range of 50 to 175 mg/m2 . Median BSA was 1.98 m2 (range of 1.4 to 2.8 m2 ). SMI, VAT, and SMD were not superior to BSA in predicting paclitaxel PK. The additive value of SMI, VAT, and SMD to BSA was also negligible. We did not find evidence that paclitaxel dosing could be further optimized by correcting for SMI, VAT, or SMD