Cancer Chemotherapy and Pharmacology最新文献

Purpose: Trametinib, a MEK1/2 inhibitor, has emerged as a promising treatment for pediatric patients with low-grade gliomas (LGG). However, trametinib exhibits significant inter-individual pharmacokinetic (PK) variability, and studies in adults demonstrated an exposure-efficacy relationship. This study aimed to evaluate the PK profile of trametinib in pediatric routine care and explore potential exposure-outcome relationships.

Methods: We analyzed PK data from 65 blood samples from 19 children receiving trametinib, either as single agent or in combination with dabrafenib. A trough concentration (Cmin) range of 8-15 ng/mL was considered, based on average exposure reported in the largest pediatric study.

Results: The mean Cmin was 8.82 ng/ml, with 64.6% of samples falling within the predefined target range, while 35.4% were below it. Regarding tolerance, 84.2% of patients experienced treatment-related toxicities, predominantly skin and subcutaneous tissue disorders. Efficacy data were limited.

Conclusion: These findings underscore the necessity of therapeutic drug monitoring in pediatric patients to optimize treatment efficacy and minimize toxicity, highlighting trametinib's potential for personalized dosing strategies in this population.

Purpose: To determine the, safety, tolerability and recommended phase 2 dosing of the combination of navitoclax, a dual Bcl-2/xL inhibitor, and vistusertib, a TORC1/2 inhibitor.

Methods: Patients with advanced solid tumors received navitoclax plus vistusertib following a 3 + 3 dose escalation design. To mitigate thrombocytopenia, a known toxicity of navitoclax, all patients received lead-in dosing of navitoclax alone at 150 mg orally daily for a minimum of 7 days. In addition to safety and tolerability, pharmacokinetics of navitoclax and vistusertib were evaluated.

Results: 14 patients received combination treatment which was well-tolerated at dose level 1 (navitoclax 150 mg orally daily plus vistusertib 35 mg orally twice daily). The main dose-limiting toxicity, grade 3 serum aminotransferase elevation, occurred in two of five patients at dose level 2 (navitoclax 250 mg orally daily plus vistusertib 35 mg orally twice daily). Navitoclax and vistusertib exposures appeared consistent with levels reported in prior studies of each agent. No responses were observed among the 8 response evaluable patients.

Conclusions: A tolerable dose of navitoclax at 150 mg orally daily plus vistusertib at 35 mg orally twice daily was identified in patients with advanced solid tumors and established as the recommended phase 2 dose (RP2D). Further efficacy assessment of this combination, in a planned phase 2 expansion in patients with relapsed small cell lung cancer, was terminated due to discontinuation of vistusertib.

Trial registration: NCT03366103 (First posted December 8, 2017).

Aim: Enfortumab vedotin is an antibody-drug conjugate (ADC) that has been approved for locally advanced or metastatic urothelial cancer, as monotherapy and in combination with pembrolizumab, and has shown significant benefit in progression-free survival and overall survival for these patients. The economic burden of enfortumab vedotin hampers widespread patient access. The aim of this study was to develop a model-informed alternative dosing regimen that results in equivalent drug exposure while reducing the costs and prevent drug spillage.

Methods: Population pharmacokinetic modelling was used to simulate a dosing regimen leading to equivalent exposure by using the published population pharmacokinetic model in the registration reports. The alternative dosing regimen was based on weight-bands derived from the established non-linear relationship between body weight and systemic exposure, and the usage of whole vials based on fixed doses to prevent spillage. Equivalent exposure compared to the approved body weight-based dosing regimen was defined as conservative equivalent boundaries of 90-111% for the calculated geometric mean ratios (GMRs) of area under the concentration-time curve and trough concentration.

Results: A weight-band based dosing regimen for each dose level of enfortumab vedotin was developed. The GMRs for all pharmacokinetic outcomes were within the predefined equivalence boundaries. In addition, a more even exposure distribution was observed across the body weight quartiles. The average costs savings across all dose levels and per weight-band were approximately 15%.

Conclusion: The proposed alternative dosing regimen shows that drug costs and spillage of enfortumab vedotin can be reduced while maintaining an equivalent and more evenly distributed exposure in treated patients.

Purpose: In 20-30% of the patients, fluoropyrimidines (5-FU) based chemotherapy leads to severe toxicity, which is associated with dihydropyridine dehydrogenase (DPD) deficiency. Therefore, DPYD genotyping became standard practice before treatment with fluoropyrimidines. Nevertheless, only 17% of the patients with severe toxicity have a DPYD variant. Therefore, an urgent need persists to investigate other strategies contributing to prediction and prevention of toxicity. Endogenous DPD substrates are considered as potential biomarkers to predict toxicity, yet contradictional data exist on demonstrating uracil as a reliable biomarker. Thymine as biomarker for toxicity has been investigated less. The aim of this study was to determine the association between the concentrations of uracil, thymine dihydrouracil (DHU) and dihydrothymine (DHT), with the systemic drug exposure of 5-FU and DPD enzyme activity in patients treated with 5-FU.

Methods: We included 36 patients with gastrointestinal malignancy who received 5-FU infusion. DPYD genotyping was conducted before start of treatment. Blood samples for determining 5-FU, uracil and thymine concentrations during infusion and DPD enzyme activity were taken.

Results: We found a significant correlation between the 5-FU systematic exposure and baseline thymine concentrations (R² = 0.1468; p = 0.0402). DPD enzyme activity was significantly correlated with baseline thymine concentrations but no correlation was found between DPD enzyme activity and 5-FU systemic drug exposure.

Conclusion: 5-FU dose individualization based on thymine concentrations could be a promising addition to DPYD genotyping to predict 5-FU-induced toxicity. Larger prospective trials are needed to examine thymine as predictor for toxicity in daily practice.

Trial registration: Trial NL7539 at 'Overview of Medical Research in the Netherlands' (ID NL-OMON21471). Date of registration 19-02-2019.

Purpose: Apply population pharmacokinetic modeling to a single institution busulfan therapeutic drug monitoring (TDM) data set from infants and children to refine dosing methods.

Methods: One-compartment pharmacokinetic model was fit to busulfan TDM data from 328 infants and children with malignant and non-malignant diseases treated with busulfan-containing transplant conditioning regimens. Age-dependence of busulfan clearance scaled to body weight and body surface area (BSA) was compared, and busulfan AUC was simulated for a BSA-scaled dose of 100 mg/m² combined with a BSA-banded dosing table for infants and children with a BSA < 0.5 m².

Results: Busulfan clearance scaled to body weight is age-dependent. Clearance in children ≤ 3 years (0.234 L/[h•kg]) is higher than the typical value for the population, (0.205 L/[h•kg]), and 48% of children < 5 years have subtherapeutic busulfan AUCs after the first dose. Busulfan clearance scaled to BSA (typical value, 5.47 L/[h•m²]) is more uniform across the pediatric age span, except for infants (≤ 1 year, 4.27 L/[h•m²]). Simulated busulfan AUCs with a dose of 100 mg/m² for patients with a BSA ≥ 0.5 m² combined with a BSA-banded dosing table for patients with a BSA < 0.5 m² achieved a therapeutic AUC after the first dose in 49% more patients than body weight scaled doses.

Conclusion: Our model predicts a greater proportion of children would achieve a therapeutic busulfan AUC after the first dose with a dose of 100 mg/m²/d combined with the infant dosing table for patients with a BSA < 0.5 m² compared to body weight-scaled dosing.

Purpose: A comprehensive analysis of metabolites (metabolomics) has been proposed as a new strategy for analyzing liquid biopsies and has been applied to identify biomarkers predicting clinical responses or adverse events associated with specific treatments. Here, we aimed to identify metabolites associated with bortezomib (Btz)-related toxicities and response to treatment in newly diagnosed multiple myeloma (MM).

Methods: Fifty-four plasma samples from transplant-ineligible MM patients enrolled in a randomized phase II study comparing two less-intensive regimens of melphalan, prednisolone and Btz (MPB) were subjected to the lipidomic profiling analysis. The amount of each lipid metabolite in plasma obtained prior to MPB therapy was compared to toxicity grades and responses to MPB therapy.

Results: High levels of 7 phospholipids (4 lysophosphatidylcholines and 3 phosphatidylcholines) were observed in cases with Btz-induced ≥ grade 2 peripheral neuropathy (BiPN) (n = 11). In addition, low levels of 3 fatty acids (FAs)-FA (18:2), FA (18:1), and FA (22:6)-were observed in patients who developed severe skin disorders ≥ grade 2 (n = 10). No metabolite significantly associated with treatment response was identified.

Conclusion: We conclude that levels of specific plasma lipid metabolites are associated with the severity of BiPN and skin disorders in patients with MM. These metabolites may serve as candidate biomarkers to predict Btz-induced toxicity in patients with MM before initiating Btz-containing therapy.

Background: ATR is an apical DDR kinase activated at damaged replication forks. Elimusertib is an oral ATR inhibitor and potentiates irinotecan in human colorectal cancer models.

Methods: To establish dose and tolerability of elimusertib with FOLFIRI, a Bayesian Optimal Interval trial design was pursued. Starting elimusertib dose was 20 mg BID days 1, 2, 15 and 16 every 28-day cycle, combined with irinotecan (150 mg/m²) and 5-FU (2000 mg/m²).

Results: The trial was stopped after 10 accruals, with four DLT across 4 dose levels including grade 3 febrile neutropenia, mucositis, nausea, vomiting and grade 4 neutropenia. The most common grade 3/4 adverse events were neutropenia, leukopenia, lymphopenia and mucositis. Based on significant toxicities the trial was stopped. PK data for 5-FU and irinotecan were unremarkable and did not account for DLTs. Among the six response evaluable patients, four had stable disease as their best response. Median PFS was 7 months. A first case of ATRi chemotherapy combination related AML (t-AML) was observed.

Conclusions: The combination of elimusertib with FOLFIRI was associated with intolerable toxicity. Combination of ATR kinases with chemotherapies that target DNA replication may be associated with significant myelotoxicity. Ongoing ATRi trials should monitor for t-AML.

Clinicaltrials:

Gov id: NCT04535401.

Purpose: Patients with partial or complete DPD deficiency have decreased capacity to degrade fluorouracil and are at risk of developing toxicity, which can be even life-threatening.

Case: A 43-year-old man with moderately differentiated rectal adenocarcinoma on capecitabine presented to the emergency department with complaints of nausea, vomiting, diarrhea, weakness, and lower abdominal pain for several days. Laboratory findings include grade 4 neutropenia (ANC 10) and thrombocytopenia (platelets 36,000). Capecitabine is used as a component of first-line adjuvant therapy by approximately 2 million patients worldwide each year. Capecitabine is metabolized to fluorouracil via the enzyme dihydropyrimidine dehydrogenase (DPD). With worsening pancytopenia and diarrhea, genetic testing for DPD deficiency was sent. Prompt treatment with uridine triacetate was initiated for presumed DPD deficiency. Unfortunately, he passed away from an infectious complication and was later confirmed to have a heterozygous DPYD*2A mutation.

Discussion: Our case demonstrates uneven testing guidelines for DPD prior to initiating 5-FU chemotherapy, appropriateness of treating with uridine triacetate, and analysis of next-generation sequencing (NGS) on tumor samples and co-incidentally obtaining germline DPD deficiency status. Our case also highlights the severe clinical impact of having DPD deficiency even with early uridine triacetate therapy.

Conclusion: It is our recommendation to perform DPD deficiency in curative intent cancer treatment and this information can increasingly be obtained in standard tumor NGS profiling, a growing norm in medical oncology.

Purpose: Histone deacetylase 6 (HDAC6) plays a critical role in tumorigenesis and tumor progression, contributing to proliferation, chemoresistance, and cell motility by regulating microtubule architecture. Despite its upregulation in melanoma tissues and cell lines, the specific biological roles of HDAC6 in melanoma are not well understood. This study aims to explore the functional effects and underlying mechanisms of WT161, a selective HDAC6 inhibitor, in melanoma cell lines.

Methods: Cell proliferation was assessed using both 2D and 3D cell culture systems, including MTT assays, spheroid growth analyses, and colony formation assays. The interaction between WT161 and the chemotherapeutic agents temozolomide (TMZ) or dacarbazine (DTIC) was evaluated using the Chou-Talalay method. Apoptotic cell death was analyzed through flow cytometry, while migration, adhesion, and invasion assays were conducted to evaluate the motility capacities of melanoma cells. Western blot assays quantified α-tubulin acetylation (Lys40), PARP cleavage, and protein levels of β-catenin and E-cadherin.

Results: WT161 significantly reduced cell growth in both 2D and 3D cultures, decreased clonogenic capacity, and showed synergistic interactions with TMZ and DTIC. The inhibitor also induced apoptotic cell death and enhanced TMZ-induced apoptosis. Additionally, WT161 reduced cell migration and invasion while increasing cell adhesion. These effects were linked to changes in β-catenin and E-cadherin levels, depending on the specific cell type evaluated.

Conclusion: Our study underscores the pivotal role of HDAC6 in melanoma progression, establishing it as a promising therapeutic target. We provide the first comprehensive evidence of WT161's anti-melanoma effects, setting the stage for further research into HDAC6 inhibitors as a potential strategy for melanoma treatment.