Enantioselective liquid chromatography–mass spectrometry assay for the determination of ifosfamide and identification of the N-dechloroethylated metabolites of ifosfamide in human plasma

A sensitive and specific liquid chromatography-mass spectrometry (LC-MS) method has been developed and validated for the enantioselective determination of ifosfamide [(R)-IF and (S)-IF] in human plasma and for the detection of the N-dechloroethylated metabolites of IF, 2-N-dechloroethylifosfamide [(R)-2-DCl-IF and (S)-2-DCl-IF] and 3-N-dechloroethylifosfamide [(R)-3-DCl-IF and (S)-3-DCl-IF]. IF, 2-DCl-IF and 3-DCl-IF were extracted from plasma using solid-phase extraction and resolved by liquid chromatography on a column containing a Chirabiotic T chiral stationary phase. The enantioselective separations were achieved using a mobile phase composed of 2-propanol:methanol (60:40 v/v) and a flow rate of 0.5 ml/min. The observed enantioselectivities (α) for IF, 2-DCl-IF and 3-DCl-IF were 1.20, 1.17 and 1.20, respectively. The calibration curve was linear in the concentration range of 37.50-4800 ng/ml for each ifosfamide enantiomer (r2 > 0.997). The lower limit of detection (LLOD) was 5.00 ng/ml. The inter- and intra-day precision ranged from 3.63 to 15.8 % relative standard deviation (RSD) and 10.1 to 14.3 % RSD, respectively, and the accuracy ranged from 89.2 to 101.5 % of the nominal values. The method was applied to the analysis of plasma samples obtained from a cancer patient who received 3.75 g/m2/d dose of (R,S)-ifosfamide as a 96-h continuous infusion

Tumor exome sequencing and copy number alterations reveal potential predictors of intrinsic resistance to multi-targeted tyrosine kinase inhibitors

Multi-targeted tyrosine kinase inhibitors (TKIs) have broad efficacy and similar FDA-approved indications, suggesting shared molecular drug targets across cancer types. Irrespective of tumor type, 20-30% of patients treated with multi-targeted TKIs demonstrate intrinsic resistance, with progressive disease as a best response. We conducted a retrospective cohort study to identify tumor (somatic) point mutations, insertion/deletions, and copy number alterations (CNA) associated with intrinsic resistance to multi-targeted TKIs. Using a candidate gene approach (n=243), tumor next-generation sequencing and CNA data was associated with resistant and non-resistant outcomes. Resistant individuals (n=11) more commonly harbored somatic point mutations in NTRK1, KDR, TGFBR2, and PTPN11 and CNA in CDK4, CDKN2B, and ERBB2 compared to non-resistant (n=26, p<0.01). Using a random forest classification model for variable reduction and a decision tree classification model, we were able to differentiate intrinsically resistant from non-resistant patients. CNA in CDK4 and CDKN2B were the most important analytical features, implicating the cyclin D pathway as a potentially important factor in resistance to multi-targeted TKIs. Replication of these results in a larger, independent patient cohort has potential to inform personalized prescribing of these widely utilized agents

Key Lessons Learned from Moffitt's Molecular Tumor Board: The Clinical Genomics Action Committee Experience

The increasing practicality of genomic sequencing technology has led to its incorporation into routine clinical practice. Successful identification and targeting of driver genomic alterations that provide proliferative and survival advantages to tumor cells have led to approval and ongoing development of several targeted cancer therapies. Within many major cancer centers, molecular tumor boards are constituted to shepherd precision medicine into clinical practice

Pilot study of rosiglitazone as an in vivo probe of paclitaxel exposure: Short report

To evaluate the use of rosiglitazone and the erythromycin breath test (ERMBT), as probes of CYP2C8 and CYP3A4, respectively, to explain inter-individual variability in paclitaxel exposure

Phase I and pharmacokinetic trial of carboplatin and albumin-bound paclitaxel, ABI-007 (Abraxane®) on three treatment schedules in patients with solid tumors

Albumin-bound paclitaxel, ABI-007 (Abraxane ®), has a different toxicity profile than solvent-based paclitaxel, including a lower rate of severe neutropenia. The combination of ABI-007 and carboplatin may have significant activity in a variety of tumor types including non-small and small cell lung cancer, ovarian cancer, and breast cancer. The purpose of this study was to determine the maximum tolerated dose (MTD) of ABI-007, on three different schedules in combination with carboplatin

A phase I evaluation of the combination of vinflunine and erlotinib in patients with refractory solid tumors

Epidermal growth factor receptor (EGFR) inhibition may overcome chemotherapy resistance by inhibiting important anti-apoptotic signals that are constitutively activated by an overstimulated EGFR pathway

Valproic acid reduces the tolerability of temsirolimus in children and adolescents with solid tumors

A pediatric study has established a maximum tolerated dose (MTD) for temsirolimus (Tem) of more than 150 mg/m2 IV/week. A phase I trial was conducted to establish the MTD for Tem in combination with valproic acid (VPA) in children and adolescents with refractory solid tumors. Secondary aims included expression of mTOR markers on archival tumor tissue; Tem pharmacokinetics (PK); assessment of histone acetylation (HA); and tumor response

Tamoxifen Dose Escalation in Patients With Diminished CYP2D6 Activity Normalizes Endoxifen Concentrations Without Increasing Toxicity

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139937/1/onco0795-sup-0002.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139937/2/onco0795-sup-0001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139937/3/onco0795.pd

PRN OPINION PAPER: Application of precision medicine across pharmacy specialty areas

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149551/1/jac51107_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149551/2/jac51107.pd

Amplification of thymidylate synthetase in metastatic colorectal cancer patients pretreated with 5-fluorouracil-based chemotherapy

Resistance to 5-fluorouracil (5-FU) represents a major contributor to cancer-related mortality in advanced colorectal cancer patients. Genetic variations and expression alterations in genes involved in 5-FU metabolism and effect have been shown to modulate 5-FU sensitivity in vitro, however these alterations do not fully explain clinical resistance to 5-FU-based chemotherapy. To determine if alterations of DNA copy number in genes involved in 5-FU metabolism impacted clinical resistance to 5-FU-based chemotherapy, we assessed thymidylate synthetase (TYMS) and thymidine phosphorylase (TYMP) copy number in colorectal liver metastases. DNA copy number of TYMS and TYMP was evaluated using real time quantitative PCR in frozen colorectal liver metastases procured from 62 patients who were pretreated with 5-FU-based chemotherapy prior to surgical resection (5-FU exposed) and from 51 patients who received no pretreatment (unexposed). Gain of TYMS DNA copy number was observed in 18% of the 5-FU exposed metastases, while only 4% of the unexposed metastases exhibited TYMS copy gain (p=0.036). No significant differences were noted in TYMP copy number alterations between 5-FU exposed and unexposed metastases. Median survival time was similar in 5-FU exposed patients with metastases containing TYMS amplification and those with no amplification. However, TYMS amplification was associated with shorter median survival in patients receiving post-resection chemotherapy (hazard ratio = 2.7, 95% confidence interval = 1.1 to 6.6; p=0.027). These results suggest amplification of TYMS amplification as a putative mechanism for clinical resistance to 5-FU-based chemotherapy and may have important ramifications for the post-resection chemotherapy choices for metastatic colorectal cancer