Dose considerations for anti-cancer drugs in metastatic prostate cancer

Non-steroidal CYP17A1 Inhibitors: Discovery and Assessment

CYP17A1 is an enzyme that plays a major role in steroidogenesis and is critically involved in the biosynthesis of steroid hormones. Therefore, it remains an attractive target in several serious hormone-dependent cancer diseases, such as prostate cancer and breast cancer. The medicinal chemistry community has been committed to the discovery and development of CYP17A1 inhibitors for many years, particularly for the treatment of castration-resistant prostate cancer. The current Perspective reflects upon the discovery and evaluation of non-steroidal CYP17A1 inhibitors from a medicinal chemistry angle. Emphasis is placed on the structural aspects of the target, key learnings from the presented chemotypes, and design guidelines for future inhibitors.

Response surface methodology for optimization of micellar-enhanced spectrofluorimetric method for assay of foretinib in bulk powder and human urine

This work investigates a sensitive and precise enhanced spectrofluorimetric assay for assay of foretinib (FTB); a tyrosine kinase inhibitor drug used for treatment of breast cancer, in tablets and urine through response surface optimization by micelle mediated protocol. The basis of the described method is the enhancement of the fluorescence behavior of FTB in Cremophor RH 40 (Cr RH 40) micellar medium and measuring the fluorescence of FTB at 344 nm after excitation at 245 nm. Optimization was performed through evaluation of diluting solvent, types of organized media, buffer type and its relevant pH. Response surface methodology was applied to obtain the optimized values of variables that mostly affect interaction of Cr RH 40 with FTB using Box-Behnken design. ICH guidelines were adhered for the validation of merit figures. Acceptable linear relationship was obtained between relative fluorescence intensity (RFI) and FTB concentrations in the range of 50 - 1000 µg L^-1, with correlation coefficient of 0.998. Accuracy was ≥ 99.82% and calculated limit of detection (LOD) was 10.60 µg L^-1. Method applications included FTB assaying in pure bulk powder. Furthermore, applications on urine samples were performed with accuracy of 100.59 ± 3.40%. The method represents echo-friendly approach and effective alternating methodology to the relevant analytical ones for FTB assaying.

UPLC-MS/MS assay for quantification of an inhibitor of kinases (Foretinib) in plasma: Application to a pharmacokinetic study in rats

Foretinib, an oral multikinase inhibitor, is known to have anti-tumor effects against cancers. The doses and the levels of foretinib vary based on the type of cancer to be treated. An accurate and precise method is required to determine the level of foretinib and its pharmacokinetics. Here, we developed such a method, which was validated based on the guidelines of the FDA and EMA. Foretinib and ibrutinib (the internal standard (IS)) were extracted using tert-butyl methyl ether. Foretinib and IS were eluted in approximately 1.2 min. Thus, a linear, fast, accurate, and precise method was developed. The calibration curve was linear (r2 ˃ 0.997) in the range of 0.5-400.0 ng/mL and the lowest limit of quantitation was 0.5 ng/mL. The average recovery, accuracy, and precision were 87.9%, 88.7%, and ≤7.8%, respectively. The analyte was deemed stable using various stability tests. The validated assay was then fruitfully applied to a pharmacokinetics study in rats, which revealed that foretinib was absorbed and the maximum concentration achieved at 4.0 h after the administration of a single dose of foretinib.

An Evaluation Approach of Cell Viability Based on Cell Detachment Assay in a Single-Channel Integrated Microfluidic Chip

Due to the heterogeneity of cancer cell populations, the traditional evaluation approach of cell viability based on the cell counting assay is quite inaccurate for the dose-response test of anticancer drugs, cell toxicology assays, and other biochemical stimulations. In this paper, an evaluation approach of cell viability based on the cell detachment assay in a single-channel integrated microfluidic chip is proposed to improve the accuracy of cell viability assessment. The electrodes are coated by fibronectin for specific cell adhesion, and it is biologically significant to study the cell detachment assay in vitro. The maximum number of cells that can be detected by this sensor is about 10⁵ cells (overgrowing), while the minimum is about 100 cells. This method is calibrated with the half-maximal inhibitory concentration assay, and the results show that the cell viability calculated by adhesion strength is more accurate than that evaluated using the cell counting assay. Meanwhile, the shear rate is transformed into shear stress for the comparability among the results in other papers. The most sensitive frequency is also determined as 1 kHz according to normalized impedance. Besides, the impedance of cell adhesion affected by different shear stresses is monitored to study the optimized plan for long-term culture of cells in the integrated microfluidic chip prepared for the cell detachment assay. Adhesion strength τ₂₅, which is the magnitude of shear stress needed to detach 75% of cell population, is introduced to describe the cell adhesion forces. It is calculated and normalized based on the cell detachment assay to evaluate cell viability. The relative errors of the cell detachment method compared with those of the cell counting method decrease by 0.637 (0% FBS), 0.586 (0.5% FBS), and 0.342 (2% FBS).

Reduced dose of cabazitaxel in metastatic castration-resistant prostate cancer: from PROSELICA trial to the real life: A single institution experience

The phase III PROSELICA trial showed that cabazitaxel 20 mg/m (C20) was not inferior and better tolerated compared to cabazitaxel 25 mg/m (C25) in patients with metastatic castration-resistant prostate cancer (mCRPC) who had progressed during or after docetaxel. Here, we report on a real-world retrospective analysis concerning the safety and the activity of C20 schedule in patients with mCRPC treated at our Institution. We identified 35 patients with mCRPC who received C20 as baseline dose treatment because they were frail or experienced serious toxicities to previous treatments. Adverse events assessment was performed at each visit during the treatment. Progression-free survival (PFS) and overall survival (OS) curves were obtained using the Kaplan-Meyer product-limit estimator. Median age was 71 years. All patients received a previous treatment with docetaxel; 19 patients (54%) received one additional line of therapy and 9 (26%) two or more. Patients received a median of 4 cycles (range: 2-10). Only one patient experienced grade 3 neutropenia (3%), two patients grade 3 anemia (6%), and one patient grade 3 fatigue (3%); three patients were treated with prophylactic Granulocyte colony-stimulating factor (9%). The most frequent adverse events of all grades were: anemia (39%), fatigue (33%), and diarrhea (15%). Median PFS was 3.7 months [95% confidence interval (CI): 3.31-4.09]; median OS was 10.3 months (95% CI: 4.63-15.97). Our real-world analysis confirms that C20 is a feasible option for elderly and heavily pretreated patients with mCRPC, showing activity and good tolerability.