Human mass balance study of TAS-102 using (14)C analyzed by accelerator mass spectrometry

The OCT2/MATE1 Interaction Between Trifluridine, Metformin and Cimetidine: A Crossover Pharmacokinetic Study

BACKGROUND AND OBJECTIVES

Trifluridine/tipiracil, registered for the treatment of patients with metastatic gastric and colorectal cancer, is a substrate and inhibitor for the organic cation transporter 2 (OCT2) and the multidrug and toxin extrusion protein 1 (MATE1), which raises the potential for drug-drug interactions with other OCT2/MATE1 modulators. Therefore, we prospectively examined the effect of an OCT2/MATE1 inhibitor (cimetidine) and substrate (metformin) on the pharmacokinetics of trifluridine.

METHODS

In this three-phase crossover study, patients with metastatic colorectal or gastric cancer were sequentially treated with trifluridine/tipiracil alone (phase A), trifluridine/tipiracil concomitant with metformin (phase B) and trifluridine/tipiracil concomitant with cimetidine (phase C). The primary endpoint was the relative difference in exposure of trifluridine assessed by the area under the curve from timepoint zero to infinity. A > 30% change in exposure was considered clinically relevant. A p-value of < 0.025 was considered significant because of a Bonferroni correction.

RESULTS

Eighteen patients were included in the analysis. Metformin did not significantly alter the exposure to trifluridine (- 12.6%; 97.5% confidence interval - 25.0, 1.8; p = 0.045). Cimetidine did alter the exposure to trifluridine significantly (+ 18.0%; 97.5% confidence interval 4.5, 33.3; p = 0.004), but this increase did not meet our threshold for clinical relevance. Metformin trough concentrations were not influenced by trifluridine/tipiracil.

CONCLUSIONS

Our result suggests that the OCT2/MATE1 modulators cimetidine and metformin can be co-administered with trifluridine/tipiracil without clinically relevant effects on drug exposure.

CLINICAL TRIAL REGISTRATION

NL8067 (registered 04-10-2019).

Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) methods for the therapeutic drug monitoring of cytotoxic anticancer drugs: An update

In the era of precision medicine, there is increasing evidence that conventional cytotoxic agents may be suitable candidates for therapeutic drug monitoring (TDM)- guided drug dosage adjustments and patient's tailored personalization of non-selective chemotherapies. To that end, many liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) assays have been developed for the quantification of conventional cytotoxic anticancer chemotherapies, that have been comprehensively and critically reviewed. The use of stable isotopically labelled internal standards (IS) of cytotoxic drugs was strikingly uncommon, accounting for only 48 % of the methods found, although their use could possible to suitably circumvent patients' samples matrix effects variability. Furthermore, this approach would increase the reliability of cytotoxic drug quantification in highly multi-mediated cancer patients with complex fluctuating pathophysiological and clinical conditions. LC-MS/MS assays can accommodate multiplexed analyses of cytotoxic drugs with optimal selectivity and specificity as well as short analytical times and, when using stable-isotopically labelled IS for quantification, provide concentrations measurements with a high degree of certainty. However, there are still organisational, pharmacological, and medical constraints to tackle before TDM of cytotoxic drugs can be more largely adopted in the clinics for contributing to our ever-lasting quest to improve cancer treatment outcomes.

Simultaneous determination of tipiracil, trifluridine and its metabolite 5-trifluoromethyluracil in human plasma using segmented polarity LC-MS/MS: A fully validated assay with clinical application

Trifluridine (FTD) and tipiracil (TPI) hydrochloride tablets (TAS-102) were used for the treatment of patients with metastatic rectal cancer that was resistant to conventional chemotherapy drugs. In this study, a rapid and sensitive liquid chromatography-tandem mass spectrometry method was developed and fully validated for the simultaneous determination of TPI, FTD, and the metabolite 5-trifluoromethyluracil (FTY) of FTD in human plasma. The plasma samples were prepared by protein precipitation. The chromatography separation was performed using ACE Excel 3 AQ (100 × 2.1 mm i.d., 1.7 µm, ACE, England) column protected by a security guard cartridge (4.0 × 2.0 mm i.d., 5 µm, Phenomenex, USA) with a gradient elution of 0.05% acetic acid in water and methanol at a flow rate of 0.35 mL/min. The MS/MS analysis was performed by using multiple reaction monitoring with the segmented polarity (positive for TPI: m/z 243.1→183.0, and negative for FTD: m/z 295.1→252.0 and FTY: m/z 178.9→158.9) electrospray ionization mode. The segmented polarity mode was designed to achieve two advantages: better sensitivity and simultaneous determination of the analytes with different ion polarities. The calibration ranges were as follows: 1.00-250 ng/ for TPI, 8.00-8000 ng/mL for FTD and 5.00-1250 ng/mL for FTY. The selectivity, accuracy, precision, matrix effect, recovery, carryover, dilution integrity and stability test results meet ICH acceptance criteria. The method was evaluated using the RGB model and successfully applied to a clinical study in patients with solid tumors. For TPI, FTD and FTY, the maximum plasma concentration was 137-147 ng/mL, 6160-6240 ng/mL and 724-725 ng/mL, respectively; the plasma elimination half-life was 1.69-1.78 h, 1.70 h, and 3.09-3.14 h, respectively, after an oral administration of 60 mg TAS-102.

Biomarkers of Trifluridine-Tipiracil Efficacy

Trifluridine/tipiracil (TAS-102) is a newer generation chemotherapy that has been approved for the later-line treatment of metastatic colorectal and gastric/gastroesophageal adenocarcinomas. The oral drug provides a modest benefit of prolongation of survival over placebo in pretreated patients with these cancers with acceptable toxicity. Studies have shown rare objective responses (2-4%), and the disease control rates were 44% in both colorectal and gastric cancer randomized trials. Thus, the majority of patients progress through treatment and are burdened by toxicities. To better characterize the sub-group of patients with a higher probability of benefit from trifluridine/tipiracil, predictive biomarkers have been sought using data from randomized trials as well as from non-randomized trials and real-world series. Biomarkers examined include clinical characteristics of the patients, laboratory tests, and tumor derived biomarkers. These studies show that early neutropenia on treatment, and ratios of leukocyte subsets, are potential biomarkers able to predict trifluridine/tipiracil benefit. Combinations of laboratory values and clinical characteristics and proteins involved in trifluridine transport and activation have been examined with initial positive results.

A phase I, open-label study evaluating the safety and pharmacokinetics of trifluridine/tipiracil in patients with advanced solid tumors and varying degrees of renal impairment

PURPOSE

Trifluridine/tipiracil (FTD/TPI) is approved for advanced colorectal and gastric/gastroesophageal cancer; however, data in patients with renal impairment (RI) are limited. This phase I study evaluated FTD/TPI in patients with advanced solid tumors and varying degrees of RI to develop dosing guidance.

METHODS

Patients were enrolled into normal renal function (CrCl ≥ 90 mL/min), mild RI (CrCl 60-89 mL/min), or moderate RI (CrCl 30-59 mL/min) cohorts and administered the recommended FTD/TPI dose (35 mg/m² twice daily, days 1-5 and 8-12; 28-day cycle). Based on interim pharmacokinetics/safety data, patients with severe RI (CrCl 15-29 mL/min) were enrolled and received FTD/TPI 20 mg/m² twice daily.

RESULTS

Forty-three patients (normal renal function [n = 12]; mild RI [n = 12]; moderate RI [n = 11]; severe RI [n = 8]) were enrolled and treated. At steady state, compared to values in patients with normal renal function, FTD area under the curve (AUC) was not significantly different in patients with RI, but TPI AUC was significantly higher and increased with RI severity. FTD/TPI safety profile was consistent with prior experience, but grade ≥ 3 adverse events (AEs) were more frequent in the RI cohorts (83.3% [mild], 90.9% [moderate], 75.0% [severe], and normal [50.0%]). Hematologic AEs (anemia and neutropenia) were more frequent with RI. Overall, seven patients discontinued because of unrelated, nonhematologic AEs.

CONCLUSION

FTD/TPI is safe and tolerable at the recommended 35 mg/m² dose in patients with mild/moderate RI and at the reduced 20 mg/m² dose in patients with severe RI.

TRIAL REGISTRATION

NCT02301117, registration date: November 21, 2014.

Post-marketing surveillance study of trifluridine/tipiracil in patients with metastatic colorectal cancer

BACKGROUND

The novel oral nucleoside antineoplastic agent trifluridine/tipiracil was approved for metastatic colorectal cancer in Japan in March 2014. In this post-marketing surveillance study, we investigated the safety and efficacy of trifluridine/tipiracil in a real-world setting, particularly haematological drug reactions classified according to the baseline renal and hepatic functions.

METHODS

We investigated patients with metastatic colorectal cancer who received trifluridine/tipiracil during the first four treatment cycles prospectively. The patients typically received 35 mg/m2 trifluridine/tipiracil twice daily on days 1-5 and 8-12 every 28 days. The primary objective was to assess the safety of trifluridine/tipiracil, but its efficacy was also evaluated.

RESULTS

Between July 2014 and June 2016, 860 patients were enrolled in the study, and the safety and efficacy of trifluridine/tipiracil were evaluated in 823 patients. Adverse drug reactions occurred in 89.7% of the patients. The most common adverse drug reactions were decreased white blood cell count (67.0%) and neutrophil count (63.9%). Haematological drug reactions of grade ≥3 were observed in 41.7% of the patients with normal renal function; 50.3, 65.6 and 78.9% of the patients had mild, moderate and severe renal impairments, respectively. Hepatic impairment was not associated with a higher incidence of haematological drug reactions. The median overall survival was 8.4 months, with a 1-year survival rate of 33.7%.

CONCLUSION

This post-marketing surveillance study further confirmed the safety and tolerability profile of trifluridine/tipiracil observed in a clinical study setting.

TAS-102: A resurrected novel Fluoropyrimidine with expanding role in the treatment of gastrointestinal malignancies

TAS-102 is an orally administered fixed-dose formulation consisting of trifluorothymidine (TFT), a fluoropyrimidine antimetabolite, and tipiracil (TPI), an inhibitor of thymidine phosphorylase (TP) that prevents rapid degradation of TFT and ensures its bioavailability. The novelty of TAS-102 lies in its antitumor activity against 5-fluorouracil (5-FU) resistant tumors, demonstrated both in the in vitro models and xenografts. The cytotoxic activity of TFT relies primarily on extensive incorporation of the TFT metabolite into the cellular DNA inducing DNA dysfunction and cell death. In contrast, 5-fluorouracil (5-FU) interferes with DNA biosynthesis by inhibiting thymidylate synthase(TS), which partly explains the absence of cross-resistance between TAS-102 and 5-FU. TAS-102 is currently approved in the third-line setting for patients with metastatic colorectal and gastric cancer based on phase III randomized clinical trial data confirming an overall survival benefit with TAS-102. The preliminary data from recently reported studies suggest a potential expanding role of TAS-102 in a variety of gastrointestinal (GI) cancers. The current article presents an overview of the pharmacology, clinical development of TAS-102, and its emerging role in the treatment of GI cancers. In addition, we discussed the rationale underlying the ongoing clinical trials investigating various combinations of TAS-102 with other anticancer agents, including targeted therapies, in a wide range of GI tumors.

Targeting Thymidine Phosphorylase With Tipiracil Hydrochloride Attenuates Thrombosis Without Increasing Risk of Bleeding in Mice

OBJECTIVE

Current antiplatelet medications increase the risk of bleeding, which leads to a clear clinical need in developing novel mechanism-based antiplatelet drugs. TYMP (Thymidine phosphorylase), a cytoplasm protein that is highly expressed in platelets, facilitates multiple agonist-induced platelet activation, and enhances thrombosis. Tipiracil hydrochloride (TPI), a selective TYMP inhibitor, has been approved by the Food and Drug Administration for clinical use. We tested the hypothesis that TPI is a safe antithrombotic medication. Approach and Results: By coexpression of TYMP and Lyn, GST (glutathione S-transferase) tagged Lyn-SH3 domain or Lyn-SH2 domain, we showed the direct evidence that TYMP binds to Lyn through both SH3 and SH2 domains, and TPI diminished the binding. TYMP deficiency significantly inhibits thrombosis in vivo in both sexes. Pretreatment of platelets with TPI rapidly inhibited collagen- and ADP-induced platelet aggregation. Under either normal or hyperlipidemic conditions, treating wild-type mice with TPI via intraperitoneal injection, intravenous injection, or gavage feeding dramatically inhibited thrombosis without inducing significant bleeding. Even at high doses, TPI has a lower bleeding side effect compared with aspirin and clopidogrel. Intravenous delivery of TPI alone or combined with tissue plasminogen activator dramatically inhibited thrombosis. Dual administration of a very low dose of aspirin and TPI, which had no antithrombotic effects when used alone, significantly inhibited thrombosis without disturbing hemostasis.

CONCLUSIONS

This study demonstrated that inhibition of TYMP, a cytoplasmic protein, attenuated multiple signaling pathways that mediate platelet activation, aggregation, and thrombosis. TPI can be used as a novel antithrombotic medication without the increase in risk of bleeding.

TAS-102 in gastric cancer: Development and perspectives of a new biochemically modulated fluroropyrimidine drug combination

TAS-102 is a preconstituted drug combination comprising an oral fluoropyrimidine (trifluridine, TFT) and a potent inhibitor of thymidine phosphorylase (tipiracil hydrochloride, TPI). TFT/TPI has recently received Food and Drug Administration (FDA) approval also for the treatment of gastric cancer after at least two lines of chemotherapy. The approval was based on a large phase 3 trial (TAGS), in which TAS-102 showed a 31 % decrease in the risk of death compared with placebo. Here, we review the pharmacological properties, clinical development and potential future directions of TAS-102 in gastric cancer.

Metabolite Profiling in Anticancer Drug Development: A Systematic Review

Drug metabolism is one of the most important pharmacokinetic processes and plays an important role during the stage of drug development. The metabolite profile investigation is important as the metabolites generated could be beneficial for therapy or leading to serious toxicity. This systematic review aims to summarize the research articles relating to the metabolite profile investigation of conventional drugs and herb-derived compounds for cancer chemotherapy, to examine factors influencing metabolite profiling of these drugs/compounds, and to determine the relationship between therapeutic efficacy and toxicity of their metabolites. The literature search was performed through PubMed and ScienceDirect databases up to January 2019. Out of 830 published articles, 78 articles were included in the analysis based on pre-defined inclusion and exclusion criteria. Both phase I and II enzymes metabolize the anticancer agents/herb-derived compounds . The major phase I reactions include oxidation/hydroxylation and hydrolysis, while the major phase II reactions are glucuronidation, methylation, and sulfation. Four main factors were found to influence metabolite formation, including species, gender, and route and dose of drug administration. Some metabolites were identified as active or toxic metabolites. This information is critical for cancer chemotherapy and anticancer drug development.

Trifluridine/Tipiracil: A Review in Metastatic Gastric Cancer

Trifluridine/tipiracil (Lonsurf^®) is a fixed-dose combination tablet comprising trifluridine, an antineoplastic nucleoside analogue, and tipiracil, a thymidine phosphorylase inhibitor. Trifluridine/tipiracil has recently been granted an additional indication in the USA for the treatment of metastatic gastric cancer, including gastroesophageal junction adenocarcinoma, in patients who have been previously treated with at least two systemic treatment regimens, and has received a positive opinion for this indication in the EU. In the large pivotal phase III TAGS trial, trifluridine/tipiracil plus best supportive care (BSC) significantly prolonged overall survival (OS; primary endpoint) compared with placebo plus BSC in this patient group. Progression-free survival (PFS) and the disease control rate were also improved with trifluridine/tipiracil relative to placebo. Health-related quality of life was not adversely affected by the addition of trifluridine/tipiracil to BSC and time to deterioration of Eastern Cooperative Oncology Group (ECOG) performance status was significantly delayed. The most common adverse events were mainly haematological (neutropenia, leucopenia and anaemia) and gastrointestinal (nausea, vomiting and diarrhoea), and were generally manageable with dosage modifications and/or supportive care. Adverse events ≥ Grade 3 were most frequently haematological in nature. Thus, trifluridine/tipiracil provides a valuable and much needed treatment option for patients with metastatic gastric or gastroesophageal junction adenocarcinoma that has progressed on at least two prior therapies.

Open-label study to evaluate trifluridine/tipiracil safety, tolerability and pharmacokinetics in patients with advanced solid tumours and hepatic impairment

AIMS

Trifluridine/tipiracil (FTD/TPI) prolongs survival in refractory metastatic colorectal cancer, but limited data exist on its use in patients with hepatic impairment. This Phase I, open-label, nonrandomized study investigated the safety, tolerability and pharmacokinetics of FTD/TPI in patients with advanced solid tumours (except breast cancer) and varying degrees of hepatic impairment, to provide dosing recommendations.

METHODS

Patients aged ≥18 years with advanced solid tumours and normal hepatic function, or mild, moderate or severe hepatic impairment according to National Cancer Institute criteria, were planned to be enrolled. Patients received FTD/TPI 35 mg/m² orally twice daily on days 1-5 and 8-12 of each 28-day cycle.

RESULTS

Twenty-four patients were enrolled to the normal hepatic function (n = 8) and mild (n = 10) and moderate (n = 6) hepatic impairment cohorts. Overall, 12 patients (50.0%) had at least 1 adverse event leading to study discontinuation. In the moderate hepatic impairment cohort, 5 of 6 patients experienced grade ≥ 3 elevation in bilirubin. No patients with severe hepatic impairment were enrolled. FTD area under the curve at steady state decreased by 18% and 22% in the mild and moderate cohorts, respectively; however, no clear change was observed in TPI area under the curve.

CONCLUSIONS

FTD/TPI can be safely administered in patients with normal hepatic function and mild hepatic impairment, with no initial dose adjustment. FTD/TPI is not recommended for use in patients with moderate hepatic impairment because of findings of grade 3 or 4 increased blood bilirubin. Therefore, FTD/TPI is not recommended for patients with moderate or severe hepatic impairment.

Contribution of equilibrative nucleoside transporter(s) to intestinal basolateral and apical transports of anticancer trifluridine

Trifluridine (FTD) exhibits anticancer activities after its oral administration despite its hydrophilic nature. It was previously reported that concentrative nucleoside transporter (CNT) 1 mediates the apical uptake of FTD in human small intestinal epithelial cells (HIECs). In the present study, FTD was also identified as a substrate for equilibrative nucleoside transporter (ENT) 1 and ENT2 in transporter gene-transfected cells. An immunocytochemical analysis revealed that ENT1 was expressed at the basolateral and apical membranes of HIECs. Cellular accumulation increased in the presence of S-(4-nitrobenzyl)-6-thioinosine (NBMPR), an ENT selective inhibitor. Cytotoxicity in HIEC monolayers at low FTD concentrations was increased by NBMPR, and this may have been due to inhibition of the ENT-mediated basolateral transport of FTD by NBMPR. These results suggest that ENTs reduce the intestinal cytotoxicity of FTD by facilitating its basolateral efflux. On the other hand, the intracellular accumulation and cytotoxicity of FTD in HIECs were decreased at higher concentrations of FTD by NBMPR, and this may have been due to the NBMPR inhibition of the apical uptake of FTD, which has been suggested to be mediated by CNTs and ENTs. In conclusion, ENTs were responsible for intestinal transepithelial permeation by mediating the basolateral efflux of FTD after its uptake by CNT1 from the apical side, resulting in decreases in its intracellular accumulation and intestinal toxicity in humans. Equilibrative nucleoside transporters may also partially contribute to the low-affinity uptake of FTD across the apical membrane along with high-affinity CNT1.

Potential role of polymorphisms in the transporter genes ENT1 and MATE1/OCT2 in predicting TAS-102 efficacy and toxicity in patients with refractory metastatic colorectal cancer

BACKGROUND

Trifluridine (FTD) is an active cytotoxic component of the metastatic colorectal cancer (mCRC) drug TAS-102, and thymidine phosphorylase inhibitor (TPI) inhibits the rapid degradation of FTD. We tested whether single nucleotide polymorphisms (SNPs) in genes involved in FTD metabolism and TPI excretion could predict outcome in patients with mCRC treated with TAS-102.

PATIENTS AND METHODS

We investigated three different cohorts: a training cohort (n = 52) and a testing cohort (n = 129) both receiving TAS-102 and a control cohort (n = 52) receiving regorafenib. SNPs of TK1, ENT1, CNT1, MATE1, MATE2 and OCT2 were analysed by polymerase chain reaction-based direct DNA sequencing.

RESULTS

In the training cohort, patients with any ENT1 rs760370 G allele had a significantly longer progression-free survival (PFS; 3.5 versus 2.1 months, respectively, hazard ratio [HR] 0.44, P = 0.004) and overall survival (OS; 8.7 versus 5.3 months, respectively, HR 0.27, P = 0.003) than the A/A genotype. These findings were validated in the testing cohort (P = 0.021 and 0.009 for PFS and OS, respectively). In addition, the combination of ENT1 rs760370, MATE1 rs2289669 and OCT2 rs316019 SNPs significantly stratified patients with the risk of PFS and OS in both cohorts (P < 0.001 for PFS and OS in the training cohort; P = 0.053 and 0.025 for PFS and OS, respectively, in the testing cohort). No significant differences were observed in the control group.

CONCLUSIONS

The combination of ENT1, MATE1 and OCT2 SNPs may serve as a predictive and prognostic marker in mCRC patients treated with TAS-102.

Trifluridine/Tipiracil: A Review in Metastatic Colorectal Cancer

Trifluridine/tipiracil (Lonsurf(®)) is a novel, orally active, antimetabolite agent comprised of trifluridine, a thymidine-based nucleoside analogue, and tipiracil, a potent thymidine phosphorylase inhibitor. Trifluridine is incorporated into DNA via phosphorylation, ultimately inhibiting cell proliferation. Tipiracil increases systemic exposure of trifluridine when coadministered. Trifluridine/tipiracil has recently been approved for the treatment of adult patients with metastatic colorectal cancer (mCRC) who are refractory to or are not considered candidates for, current standard chemotherapy and biological therapy in the EU and USA and in unresectable advanced or recurrent CRC in Japan. The approved regimen of oral twice-daily trifluridine/tipiracil (35 mg/m(2) twice daily on days 1-5 and 8-12 of each 28-day cycle) significantly improved overall survival and progression-free survival and was associated with a significantly higher disease control rate than placebo when added to best supportive care in the multinational, pivotal phase III trial (RECOURSE) and a phase II Japanese trial. Trifluridine/tipiracil was associated with an acceptable tolerability profile, with adverse events generally being managed with dose reductions, temporary interruptions in treatment or administration of granulocyte-colony stimulating factor. The most common grade 3-4 adverse events (≥10 %) were anaemia, neutropenia, thrombocytopenia and leukopenia. In conclusion, trifluridine/tipiracil is a useful additional treatment option for the management of mCRC in patients who are refractory to, or are not considered candidates for, currently available therapies.

Use of Accelerator Mass Spectrometry in Human Health and Molecular Toxicology

Accelerator mass spectrometry (AMS) has been adopted as a powerful bioanalytical method for human studies in the areas of pharmacology and toxicology. The exquisite sensitivity (10-18 mol) of AMS has facilitated studies of toxins and drugs at environmentally and physiologically relevant concentrations in humans. Such studies include risk assessment of environmental toxicants, drug candidate selection, absolute bioavailability determination, and more recently, assessment of drug-target binding as a biomarker of response to chemotherapy. Combining AMS with complementary capabilities such as high performance liquid chromatography (HPLC) can maximize data within a single experiment and provide additional insight when assessing drugs and toxins, such as metabolic profiling. Recent advances in the AMS technology at Lawrence Livermore National Laboratory have allowed for direct coupling of AMS with complementary capabilities such as HPLC via a liquid sample moving wire interface, offering greater sensitivity compared to that of graphite-based analysis, therefore enabling the use of lower 14C and chemical doses, which are imperative for clinical testing. The aim of this review is to highlight the recent efforts in human studies using AMS, including technological advancements and discussion of the continued promise of AMS for innovative clinical based research.

Regulatory aspects of human radiolabeled mass balance studies in oncology: concise review

Human radiolabeled mass balance studies are performed to obtain information about the absorption, distribution, metabolism, and excretion of a drug in development. The main goals are to determine the route of elimination and major metabolic pathways. This review provides an overview of the current regulatory guidelines concerning human radiolabeled mass balance studies and discusses scientific trends seen in the last decade with a focus on mass balance studies of anticancer drugs. This paper also provides an overview of mass balance studies of anticancer agents that were executed in the last 10 years.