Tumor Lysis Syndrome in a Patient with BRAFV600E Mutated Colon Cancer Treated with Cetuximab and Encorafenib.

Tumor lysis syndrome (TLS) is a fatal complication associated with chemotherapy. We herein report a case of TLS in a 73-year-old woman with metastatic BRAFV600E mutated colon cancer after she received combined treatment with cetuximab and encorafenib. The serum uric acid, urea nitrogen, and creatinine levels were elevated on day four of the first cycle. The fibrin degradation product (FDP) and D-dimer levels were also high. Diuresis and rasburicase were initiated for TLS, and the laboratory data all normalized on day 8. Thus, the possibility of TLS being induced by targeted drugs in patients with solid tumors, including colorectal cancer, must not be overlooked.

Pharmacokinetics of gefitinib in elderly patients with EGFR-mutated advanced non-small cell lung cancer: a prospective study.

BACKGROUND: Gefitinib is recommended as a first-line treatment option for elderly patients with non-small cell lung cancer (NSCLC). Because no pharmacokinetics of gefitinib have been examined, we prospectively assessed the pharmacokinetics of gefitinib in patients with epidermal growth factor receptor gene-mutated advanced NSCLC who were 75 years or older. METHODS: Gefitinib was orally administered once daily at a dose of 250 mg. The concentrations of gefitinib and its major metabolite O-desmethyl gefitinib in plasma were measured by high-performance liquid chromatography. The area under the plasma concentration-time curve from time 0 to 48 h (AUC0-48) was calculated. Polymorphisms in CYP3A5, CYP2D6, ABCG2, ABCB1, and OATP1B1 were analyzed by direct sequencing. RESULTS: Eighteen patients with a median age of 80.5 years (range, 75-89) with adequate liver and kidney functions were examined. AUC0-48 values of gefitinib and O-desmethyl gefitinib in this population were 9.49 ± 3.5 and 10.6 ± 14 µM h, respectively. Compared to the gefitinib pharmacokinetics observed in a previous phase I study in Japan, systemic exposure to gefitinib in elderly patients was slightly higher than that in younger patients. Three patients experienced grade 3 diarrhea, increases in alanine aminotransferase, and aspartate aminotransferase levels 30 days after starting gefitinib treatment. The CYP2D6 genotype was associated with CYP2D6-mediated metabolism of gefitinib to O-desmethyl gefitinib. CONCLUSIONS: We demonstrated for the first time the systemic exposure to gefitinib in elderly patients with NSCLC. TRIAL REGISTRATION: The study was registered with the University Hospital Medical Information Network-Clinical Trials Registry Japan (UMIN000026409) on November 8, 2013.

Characteristics of miRNA-SNPs in healthy Japanese subjects and non-small cell lung cancer, colorectal cancer, and soft tissue sarcoma patients.

Single nucleotide polymorphisms in genes encoding microRNAs (miRNA-SNPs) may affect the maturation steps of miRNAs or target mRNA recognition, leading to changes in the expression of target mRNAs to cause gain- or loss-of-function changes. Several miRNA-SNPs are known to be associated with the risk of diseases such as cancer. The purpose of this study was to comprehensively determine the miRNA-SNPs in Japanese individuals to evaluate the differences in allele frequencies between ethnicities by comparing data from the global population in the 1000 Genomes Project and differences between healthy subjects and cancer patients. We performed next-generation sequencing targeting genes encoding 1809 pre-miRNAs. As a result, 403 miRNA-SNPs (146 miRNA-SNPs per subject on average) were identified in 28 healthy Japanese subjects. We observed significant differences in the allele frequencies between ethnicities in 33 of the 403 miRNA-SNPs. The numbers of miRNA-SNPs per subject in 44 non-small cell lung cancer (NSCLC), 33 colorectal cancer (CRC), and 15 soft tissue sarcoma (STS) patients were almost equal to those in healthy subjects. Significant differences in allele frequencies were observed for 14, 11, and 9 miRNA-SNPs in NSCLC, CRC, and STS patients compared with the frequencies in healthy subjects, suggesting that these SNPs can be biomarkers of risk for each type of cancer assessed. In summary, we comprehensively characterized miRNA-SNPs in Japanese individuals and found differences in allele frequencies of several miRNA-SNPs between ethnicities and between healthy subjects and cancer patients. Studies investigating a larger number of subjects should be performed to confirm the potential of miRNA-SNPs as biomarkers of cancer risk.

Minimal contribution of the hepatic uptake transporter OATP1B1 to the inter-individual variability in SN-38 pharmacokinetics in cancer patients without severe renal failure.

PURPOSE: SN-38, a pharmacologically active metabolite of irinotecan, is taken up into hepatocytes by organic anion transporting polypeptide (OATP) 1B1. The effects of functional OATP1B1 521T>C on the pharmacokinetics of SN-38 remain controversial. Here, we prospectively examined the effects of OATP1B1 function on the area under the plasma total or unbound concentration-time curve (tAUC or uAUC) of SN-38 by assessing OATP1B1 521T>C and the plasma levels of endogenous OATP1B1 substrates, coproporphyrin (CP)-I and III, in cancer patients treated with irinotecan. METHODS: We enrolled cancer patients who were treated with an irinotecan-containing regimen and did not have severe renal failure. The total and unbound concentrations of SN-38 in the plasma were measured by high-performance liquid chromatography. AUC values were calculated and normalized to the actual irinotecan dose (AUC/dose). The OATP1B1 521T>C was analyzed by direct sequencing. Concentrations of the endogenous substrates in plasma before irinotecan treatment (baseline) were determined by liquid chromatography with tandem mass spectrometry. RESULTS: Twenty-two patients with a median estimated glomerular filtration rate of 74.8 mL/min (range 32.6-99.6) were examined. Both tAUC/dose and uAUC/dose were associated with the grade of neutropenia; however, they were not associated with OATP1B1 521T>C or baseline CP-I and III levels. It is worth noting that these baseline concentrations were significantly higher in patients with OATP1B1 521C, supporting functional changes in OATP1B1. CONCLUSION: The contribution of OATP1B1 activity to inter-patient variability in the systemic exposure to SN-38 is likely minimal in patients without severe renal failure.

Alteration in the Plasma Concentrations of Endogenous Organic Anion-Transporting Polypeptide 1B Biomarkers in Patients with Non-Small Cell Lung Cancer Treated with Paclitaxel.

Paclitaxel has been considered to cause OATP1B-mediated drug-drug interactions at therapeutic doses; however, its clinical relevance has not been demonstrated. This study aimed to elucidate in vivo inhibition potency of paclitaxel against OATP1B1 and OATP1B3 using endogenous OATP1B biomarkers. Paclitaxel is an inhibitor of OATP1B1 and OATP1B3, with Ki of 0.579 ± 0.107 and 5.29 ± 3.87 µM, respectively. Preincubation potentiated its inhibitory effect on both OATP1B1 and OATP1B3, with Ki of 0.154 ± 0.031 and 0.624 ± 0.183 µM, respectively. Ten patients with non-small cell lung cancer who received 200 mg/m2 of paclitaxel by a 3-hour infusion were recruited. Plasma concentrations of 10 endogenous OATP1B biomarkers-namely, coproporphyrin I, coproporphyrin III, glycochenodeoxycholate-3-sulfate, glycochenodeoxycholate-3-glucuronide, glycodeoxycholate-3-sulfate, glycodeoxycholate-3-glucuronide, lithocholate-3-sulfate, glycolithocholate-3-sulfate, taurolithocholate-3-sulfate, and chenodeoxycholate-24-glucuronide-were determined in the patients with non-small cell lung cancer on the day before paclitaxel administration and after the end of paclitaxel infusion for 7 hours. Paclitaxel increased the area under the plasma concentration-time curve (AUC) of the endogenous biomarkers 2- to 4-fold, although a few patients did not show any increment in the AUC ratios of lithocholate-3-sulfate, glycolithocholate-3-sulfate, and taurolithocholate-3-sulfate. Therapeutic doses of paclitaxel for the treatment of non-small cell lung cancer (200 mg/m2) will cause significant OATP1B1 inhibition during and at the end of the infusion. This is the first demonstration that endogenous OATP1B biomarkers could serve as surrogate biomarkers in patients. SIGNIFICANCE STATEMENT: Endogenous biomarkers can address practical and ethical issues in elucidating transporter-mediated drug-drug interaction (DDI) risks of anticancer drugs clinically. We could elucidate a significant increment of the plasma concentrations of endogenous OATP1B biomarkers after a 3-hour infusion (200 mg/m2) of paclitaxel, a time-dependent inhibitor of OATP1B, in patients with non-small cell lung cancer. The endogenous OATP1B biomarkers are useful to assess the possibility of OATP1B-mediated DDIs in patients and help in appropriately designing a dosing schedule to avoid the DDIs.

Higher Systemic Exposure to Unbound Active Metabolites of Regorafenib Is Associated With Short Progression-Free Survival in Colorectal Cancer Patients.

Regorafenib treatment improves survival of patients with metastatic colorectal cancer, but it is also characterized by detrimental side effects that may require modified dosing or interval schedules. Regorafenib is metabolized by cytochrome P450 3A4 in the liver to its active metabolites, M-2 and M-5. We examined area under the unbound plasma concentration-time curve (AUCu) to these compounds to establish pharmacokinetic bases for individualized dosing strategies. The plasma protein binding of M-2 and M-5 was approximately 10-fold lower than that of regorafenib, whereas AUCu values for active metabolites on both days 1 and 15 were significantly higher than that of regorafenib. Patients with higher AUCu values of M-2 or M-5 on day 1 showed significantly shorter progression-free survival than others, likely due, at least in part, to treatment discontinuation as a result of adverse events, especially occurred during first cycle.

High-throughput method to analyze tegafur and 5-fluorouracil in human tears and plasma using hydrophilic interaction liquid chromatography/tandem mass spectrometry.

RATIONALE: We developed a new high-throughput method to analyze tegafur (FT) and 5-fluorouracil (5-FU) in tear and plasma samples using hydrophilic interaction liquid chromatography (HILIC)/tandem mass spectrometry (MS/MS). METHODS: The tear samples (10 µL) spiked with FT, 5-FU, and 5-chlorouracil (internal standard) were diluted using 40 µL of 2 M ammonium acetate and 250 µL of acetonitrile with 2% formic acid; 20 µL of plasma spiked with the two drugs and internal standard was diluted with 80 µL of 2 M ammonium acetate and 500 µL of acetonitrile with 2% formic acid. After centrifugation, the clear supernatant extract (15 µL) was directly injected into the HILIC/MS/MS instrument, and each drug was separated on a Unison UK-Amino column (50 mm × 3 mm i.d., 3 µm particle size) with a linear gradient elution system composed of 10 mM ammonium acetate (pH 6.8) and acetonitrile at a flow rate of 0.7 mL/min. We performed quantification by multiple reaction monitoring (MRM) with negative-ion atmospheric-pressure chemical ionization. RESULTS: Distinct peaks were observed for the drugs on each MRM channel within 2 min. The regression equations showed good linearity within the range 0.04-4.0 µg/mL for the tear and plasma samples with detection limits at 0.02-0.04 µg/mL. Recoveries for target analytes (FT and 5-FU) for the tear and plasma samples were in the 94-128% and 94-104% ranges, respectively. The intra- and inter-day coefficients of variation for the two drugs were lower than 10.8%. The accuracies of quantitation were 97-115% for both samples. CONCLUSIONS: We established a high-throughput, reproducible, and practical procedure for analyzing FT and 5-FU in human tear and plasma samples using HILIC/MS/MS analysis with an aminopropyl-bonded mixed-mode separation column. This method can be applied to the high-throughput routines used in clinical analyses.

Does Industry-Conducted All-Case Surveillance of Newly Approved Oncology Drugs Contribute to the Revision of Package Inserts in Japan?

In Japan, the Pharmaceuticals and Medical Devices Agency requires all-case surveillance studies (ACSS) for many novel oncology drugs as a condition for approval. However, this is a major burden on the pharmaceutical industry and clinicians. The objective of this analysis was to investigate whether ACSS can contribute essential new information on severe adverse drug reactions, which are necessary to revise the package inserts of drugs. All oncology drugs for which ACSS were required from January 2006-September 2015 found on the Pharmaceuticals and Medical Devices Agency website were reviewed, and the influence of ACSS on the package insert content was evaluated. Most of the package insert revisions regarding serious treatment-related adverse events were based on spontaneous reports from clinicians. The contribution of ACSS results to the revision of package inserts is limited and comes at the cost of financial resources and labor. An alternative, more efficient adverse-event reporting system is necessary.

Rabeprazole intake does not affect systemic exposure to capecitabine and its metabolites, 5'-deoxy-5-fluorocytidine, 5'-deoxy-5-fluorouridine, and 5-fluorouracil.

PURPOSE: Several retrospective studies have shown that the antitumor efficacy of capecitabine-containing chemotherapy decreases when co-administered with a proton pump inhibitor (PPI). Although a reduction in capecitabine absorption by PPIs was proposed as the underlying mechanism, the effects of PPIs on capecitabine pharmacokinetics remain unclear. We prospectively examined the effects of rabeprazole on the pharmacokinetics of capecitabine and its metabolites. METHODS: We enrolled patients administered adjuvant capecitabine plus oxaliplatin (CapeOX) for postoperative colorectal cancer (CRC) patients and metastatic CRC patients receiving CapeOX with/without bevacizumab. Patients receiving a PPI before registration were allocated to the rabeprazole group, and the PPI was changed to rabeprazole (20 mg/day) at least 1 week before the initiation of capecitabine treatment. On day 1, oral capecitabine (1000 mg/m2) was administered 1 h after rabeprazole intake. Oxaliplatin (and bevacizumab) administration on day 1 was shifted to day 2 for pharmacokinetic analysis of the first capecitabine dose. Plasma concentrations of capecitabine, 5'-deoxy-5-fluorocytidine, 5'-deoxy-5-fluorouridine, and 5-fluorouracil were analyzed by high-performance liquid chromatography. Effects of rabeprazole on inhibition of cell proliferation by each capecitabine metabolite were examined with colon cancer cells (COLO205 and HCT116). RESULTS: Five and 9 patients enrolled between September 2017 and July 2018 were allocated to rabeprazole and control groups, respectively. No significant effects of rabeprazole on area under the plasma concentration-time curve divided by capecitabine dose for capecitabine and its three metabolites were observed. Rabeprazole did not affect the proliferation inhibition of colon cancer cells by the respective capecitabine metabolites. CONCLUSION: Rabeprazole does not affect capecitabine pharmacokinetics.

Influx and Efflux Transporters Contribute to the Increased Dermal Exposure to Active Metabolite of Regorafenib After Repeated Oral Administration in Mice.

The multikinase inhibitor regorafenib, which is a standard treatment for certain cancer patients after disease progression following other approved therapies, exhibits delayed-onset dermal toxicity. Here, we aimed to clarify the mechanisms that contribute to the increased dermal exposure to active metabolite M-5 of regorafenib after repeated oral administration. The dermal concentration of M-5 at 24 h after the last 5 oral administrations of regorafenib in mdr1a/1b/bcrp-/- mice was more than 190 times that in wild-type mice. The skin-to-plasma concentration ratio of M-5 in mdr1a/1b/bcrp-/- was also higher than in wild-type mice, suggesting possible involvement of P-glycoprotein and breast cancer resistance protein in regulating the dermal distribution. The area under the plasma concentration-time curve values of M-5 and its precursor M-2 in plasma of mdr1a/1b/bcrp-/- were at most 26 and 3 times those in wild-type mice, respectively. Interestingly, repeated administration of regorafenib markedly increased the area under the plasma concentration-time curve of M-5 in plasma, but not liver, compared with a single dose. Intravenous administration of M-5 dose-dependently reduced the liver-to-plasma concentration ratio. Our results indicate that hepatic uptake of M-5 may partially explain the accumulation of M-5 in the systemic circulation, but multiple factors, including influx and efflux transporters, are involved in determining dermal exposure to M-5.

Coadministration of cytotoxic chemotherapeutic agents with irinotecan is a risk factor for irinotecan-induced cholinergic syndrome in Japanese patients with cancer.

BACKGROUND: Cholinergic syndrome is an acute adverse event frequently observed in patients administered irinotecan, and can sometimes negatively affect their quality of life. In some manifestations of the syndrome such as bradycardia, careful monitoring of patients is advised. In this study, we retrospectively investigated the risk factors associated with irinotecan-induced cholinergic syndrome in Japanese patients with cancer. METHODS: Patients who received irinotecan-based chemotherapy between April 2014 and June 2018 were examined. Patient backgrounds and clinical data during the first cycle of an irinotecan-containing regimen, including cholinergic syndrome manifestation within 24 h after the start of treatment, were collected from medical records. Univariate and multivariate analyses were performed to assess the risk of irinotecan-induced cholinergic syndrome. RESULTS: Among 179 patients administered an irinotecan-containing regimen, 51 experienced cholinergic syndrome after the initiation of treatment. The most common symptom was sweating followed by diarrhea, abdominal pain, lacrimation, and nasal discharge. 42 patients developed symptoms of cholinergic syndrome during their first treatment with irinotecan. Multivariate analyses revealed that the incidences of cholinergic syndrome in patients administered 2 or 3 chemotherapeutic agents; i.e., irinotecan plus 1 or 2 other cytotoxic anticancer drug(s), were significantly higher than that in patients administered irinotecan alone [odds ratio (OR) 4.35, 95% confidence interval (CI) 1.5-12, p = 0.0053 and OR 4.50, 95% CI 1.5-14, p = 0.0093, respectively]. The addition of a molecularly targeted drug did not affect the incidence of cholinergic syndrome. CONCLUSION: The incidence rate of irinotecan-induced cholinergic syndrome increased concomitantly with the addition of cytotoxic chemotherapeutic agents administered.

Lack of correlation between the costs of anticancer drugs and clinical benefits in Japan.

Both overall survival (OS) and progression-free survival (PFS) are primary endpoints of phase III studies of new anticancer drugs. Medical care expenditures, especially oncology drug prices, are rapidly increasing; however, the impact of oncology drug prices on OS and PFS is unclear. We analyzed the relationship between oncology drug prices and clinical outcomes in Japan. The costs of a full course or 1 year of treatment were estimated on the basis of the latest National Health Insurance Drug Price Standards, and the relationship between costs and improvements in OS or PFS obtained with each drug were analyzed. Cost-effectiveness was compared between new-class drugs and next-in-class drugs. We then developed a simple model for estimating the costs required to prolong OS and PFS by 1 day and used this model to compare cost-effectiveness. Drug costs were not significantly related to treatment outcomes in terms of PFS or OS. There was no significant difference in the median cost between novel drugs and the next-in-class drugs (P = 0.39). The oncology drug cost required to prolong PFS by 1 day was more expensive than the drug cost required for prolong OS by 1 day. Prices of oncology drugs should be decided on the basis of actual clinical benefits for cancer patients, and the drug price evaluation process should be disclosed in Japan.

Organic Cation Transporter 1 Is Responsible for Hepatocellular Uptake of the Tyrosine Kinase Inhibitor Pazopanib.

Pazopanib is an orally active tyrosine kinase inhibitor that exhibits hepatotoxicity in some patients. Despite the clinical importance of its hepatic distribution, the transporter(s) responsible for hepatic uptake of pazopanib in humans remain undetermined. To characterize its hepatic uptake mechanism, we screened the effects of several transporter inhibitors, including tetrapentylammonium (TPeA) for organic cation transporters (OCTs) and cyclosporin A (CsA) for organic anion-transporting polypeptides (OATPs), on both plasma disappearance and hepatic distribution of pazopanib in mice after its i.v. administration. Among the inhibitors, TPeA largely reduced hepatic distribution and plasma clearance of pazopanib, whereas CsA showed only partial reduction. Pazopanib uptake by isolated mouse hepatocytes was similarly reduced by these inhibitors, suggesting that OCTs play a major role in the overall hepatic uptake of pazopanib in mice. In human embryonic kidney cell line HEK293 cells stably transfected with human OCT1, pazopanib uptake was significantly higher than that in vector-transfected cells. Moreover, pazopanib uptake by OCT1 became saturated and was inhibited by TPeA, but not by CsA, confirming that pazopanib is also a substrate of human OCT1. Importantly, OCT1-mediated uptake of a typical OCT1 substrate metformin was inhibited by pazopanib with an IC50 value of 0.253 µM, indicating that pazopanib has the potential for clinically relevant inhibition of human OCT1. Finally, pazopanib was taken up by cryopreserved human pooled hepatocytes in a time-dependent manner, and this uptake was largely reduced by TPeA but only partially reduced by CsA. Thus, the present findings suggest that OCT1 is responsible for hepatocellular uptake of pazopanib.

A phase I/II pharmacokinetics/pharmacodynamics study of irinotecan combined with S-1 for recurrent/metastatic breast cancer in patients with selected UGT1A1 genotypes (the JBCRG-M01 study).

S-1 and irinotecan combination is attractive for breast cancer refractory to anthracyclines and taxanes. Patients with advanced human epidermal growth factor receptor 2 (HER2)-negative breast cancer previously treated with anthracyclines and taxanes were eligible. Patients with brain metastases and homozygous for UGT1A1 *6 or *28 or compound heterozygous (*6/*28) were excluded. A dose-escalation design was chosen for the phase I portion (level 1: irinotecan 80 mg/m2  days 1-8 and S-1 80 mg/m2  days 1-14 every 3 weeks; level 2: irinotecan 100 mg/m2 and S-1 80 mg/m2 ). Study objectives included determination of the recommended dose for phase II, response rate, progression-free survival (PFS), and safety. Pharmacokinetics and CD34+ circulating endothelial cells (CECs) as pharmacodynamics were also analyzed. Thirty-seven patients were included. One patient at each level developed dose-limiting toxicities; therefore, level 2 was the recommended dose for phase II. Diarrhea was more common in patients possessing a *6 or *28 allele compared with wild-type homozygous patients (46% and 25%). Among 29 patients treated at level 2, PFS was longer for UGT1A1 wt/*6 and wt/*28 patients than for wt/wt patients (12 vs. 8 months, P = 0.06). PFS was significantly longer in patients with a larger-than-median SN-38 area under the curve (AUC) than in those with a smaller AUC (P = 0.039). There was an association between clinical benefit and reduction in baseline CD34+ CECs by S-1 (P = 0.047). The combination of irinotecan and S-1 is effective and warrants further investigation.

Comparison of adverse events following injection of original or generic docetaxel for the treatment of breast cancer.

PURPOSE: The approval of injectable generic drugs does not require bioequivalence testing. However, although generic products contain the same level of the active compound, the levels and types of additives present can differ from those used in the original product. Since docetaxel is highly lipophilic, polysorbate 80 (PS80), polyethylene glycol (PEG), and ethyl alcohol are employed to solubilize this anticancer agent. This retrospective study compared the safety of five docetaxel products (Taxotere®, Docetaxel Hospira, Docetaxel Sandoz, Docetaxel Sawai, and Docetaxel EE). METHODS: The incidence and severity of adverse events were analyzed using the medical records of operable breast cancer patients (n = 363) treated with docetaxel (75 mg/m2) in Showa University Hospital, Japan, from Jan 2013 to Mar 2016. Toxicities were graded using the Common Terminology Criteria for Adverse Events, version 4.0. RESULTS: Significant product-related differences were observed in the following non-hematological adverse events: injection site reaction (P = 0.0012), hand-foot syndrome (≥grade 3) (P = 0.0003), and oral mucositis (≥grade 3) (P = 0.0080). Multivariate logistic regression analyses of the associations between these adverse events and the total additive administered (g/m2) identified significant negative effects of PS80 and ethyl alcohol. CONCLUSIONS: Injectable docetaxel products had different adverse event profiles, which showed negative associations with the amounts of PS80 and ethyl alcohol present. This finding indicated that there might be additive-related pharmacokinetic and physiochemical differences among these products, suggesting a need for further pre- or post-approval testing of injectable generic products containing noticeable different levels of additives.

S-1 and oxaliplatin (SOX) plus bevacizumab versus mFOLFOX6 plus bevacizumab as first-line treatment for patients with metastatic colorectal cancer: updated overall survival analyses of the open-label, non-inferiority, randomised phase III: SOFT study.

OBJECTIVE: The SOFT study previously demonstrated that S-1 and oxaliplatin (SOX) plus bevacizumab was non-inferior to l-leucovorin, fluorouracil and oxaliplatin (mFOLFOX6) plus bevacizumab in terms of the primary end point of progression-free survival (PFS) as first-line chemotherapy for metastatic colorectal cancer (mCRC). The overall survival (OS) data were immature at the time of the primary analysis. METHODS: A total of 512 patients were enrolled and randomly assigned to receive either mFOLFOX6 plus bevacizumab (5 mg/kg of bevacizumab, followed by 200 mg/m2 of l-leucovorin given simultaneously with 85 mg/m2 of oxaliplatin, followed by a 400 mg/m2 bolus of 5-FU on day 1 and then 2400 mg/m2 of 5-FU as an intravenous infusion over the course of 46 hours, every 2 weeks) or SOX plus bevacizumab (7.5 mg/kg of bevacizumab, 130 mg/m2 of oxaliplatin on day 1 and 40-60 mg of S-1 two times per day for 2 weeks, followed by a 1-week rest). The primary end point was PFS. After the primary analysis, the follow-up survey was cut-off on 30 September 2013, and the final OS data were analysed. RESULTS: With a median follow-up of 37.7 months, the median survival time (MST) was 29.7 months with mFOLFOX6 plus bevacizumab and 29.6 months with SOX plus bevacizumab (HR, 1.018; 95% CI 0.823 to 1.258). Median PFS was 11.7 months in the mFOLFOX6 plus bevacizumab group and 12.2 months in the SOX plus bevacizumab group (HR, 1.051; 95% CI 0.876 to 1.262; pnon-inferiority=0.0115). CONCLUSION: Our results reconfirmed that SOX plus bevacizumab is non-inferior to mFOLFOX6 plus bevacizumab in terms of PFS. MST did not differ between the groups. SOX plus bevacizumab is considered an effective regimen for first-line chemotherapy in patients with mCRC and can be used instead of mFOLFOX6 plus bevacizumab. TRIAL REGISTRATION NUMBER: JapicCTI-090699.

Incidence of Ophthalmic Disorders in Patients Treated with the Antineoplastic Agent S-1.

S-1 is an oral antineoplastic agent containing tegafur, gimeracil, and oteracil potassium. Recently, ophthalmic disorders, particularly epiphora, have been reported. We retrospectively investigated the incidence of ophthalmic disorders in patients treated with a regimen containing S-1 at our institution. Ophthalmic disorders were noted in 28 of 261 patients(10.7%). These included epiphora(17 cases), eye discharge(10 cases), conjunctivitis(6cases ), blurred vision(3 cases), and eye discomfort(2 cases), as well as eye pain, pruritus, dry eye, hordeolum, and visual loss(1 case each). The median time from starting treatment to appearance of the condition was 3.0(interquartile range 1.5-4.5)months and the median cumulative S-1 dose was 4.2(interquartile range 2.2-9.5)g. More men than women developed ophthalmic disorders on S-1. The median total dose and duration of treatment were higher in those developed ophthalmic disorders than in those who did not (12.4 g vs 6.3g and 8.6 months vs 4.4 months). Epiphora was the most common of a number of ophthalmic disorders seen in our patients treated with S-1. Patients and physicians should be fully informed of the potential association between S-1 and ophthalmic disorders, and patients receiving this treatment need to be carefully monitored.

Involvement of the Transporters P-Glycoprotein and Breast Cancer Resistance Protein in Dermal Distribution of the Multikinase Inhibitor Regorafenib and Its Active Metabolites.

Regorafenib is a multikinase inhibitor orally administered to colorectal cancer patients, and is known to often exhibit dermal toxicity. The purpose of this study is to clarify possible involvement of P-glycoprotein and breast cancer resistance protein (BCRP) in the dermal accumulation of regorafenib and its active metabolites M-2 and M-5. Following intravenous administration in triple knockout (Abcb1a/1b/bcrp-/-; TKO) and wild-type (WT) mice, delayed plasma clearance of M-2 and M-5, but not regorafenib, was observed in TKO mice compared to WT mice. Elacridar, an inhibitor of both transporters, also caused delayed clearance of M-2 and M-5, suggesting that these transporters are involved in their elimination. Skin-to-plasma concentration ratios of regorafenib, M-2, and M-5 were significantly higher in TKO mice than in WT mice. Elacridar increased skin-to-plasma and epidermis-to-plasma concentration ratios of regorafenib. Basal-to-apical transport of M-2 and M-5 was observed in LLC-PK1-Pgp and MDCKII/BCRP/PDZK1 cells, which was inhibited by elacridar and the BCRP inhibitor Ko143, respectively. The present findings thus indicate that P-glycoprotein and BCRP are involved in the accumulation of regorafenib and its active metabolites in the skin, by affecting either their systemic exposure or their plasma distribution in the circulating blood.

Nab-paclitaxel versus solvent-based paclitaxel in patients with previously treated advanced gastric cancer (ABSOLUTE): an open-label, randomised, non-inferiority, phase 3 trial.

BACKGROUND: Weekly administration of solvent-based paclitaxel is one of the standard second-line chemotherapy regimens for advanced gastric cancer. Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) was developed to improve the solubility of paclitaxel and does not need premedication to avoid infusion-related reactions associated with solvent-based paclitaxel. Additionally, higher doses of nab-paclitaxel can be administered over a shorter infusion time and at higher drug concentrations compared with solvent-based paclitaxel. We aimed to investigate the efficacy and safety of nab-paclitaxel versus solvent-based paclitaxel in patients with previously treated advanced gastric cancer. METHODS: We did a randomised, open-label, non-inferiority, phase 3 trial at 72 institutions in Japan. Patients aged 20 years or older with advanced gastric adenocarcinoma refractory to a fluoropyrimidine-containing first-line chemotherapy regimen, with progressive disease or a relapse fewer than 24 weeks after the final dose of adjuvant chemotherapy were randomly assigned (1:1:1) to receive intravenous nab-paclitaxel (260 mg/m2) every 3 weeks (on day 1 of a 21-day cycle), weekly nab-paclitaxel (100 mg/m2, on days 1, 8, and 15 of a 28-day cycle), or weekly solvent-based paclitaxel (80 mg/m2, on days 1, 8, and 15 of a 28-day cycle). Randomisation was done with the minimisation method, with stratification for previous use of docetaxel, presence of peritoneal metastases, and Eastern Cooperative Oncology Group (ECOG) performance status. The primary endpoint was overall survival in the full analysis set, which included all randomly assigned patients who received at least one dose of study drug, with a non-inferiority margin of 1·25 for the hazard ratio. This trial is registered with Japan Pharmaceutical Information Center Clinical Trial, number JapicCTI-132059, and has been completed. FINDINGS: Between March 13, 2013, and May 14, 2015, 741 patients were randomly assigned to nab-paclitaxel every 3 weeks (n=247), weekly nab-paclitaxel (n=246), or weekly solvent-based paclitaxel (n=248). Median follow-up for overall survival was 9·99 months (IQR 6·05-15·05). Median overall survival was 10·3 months (95% CI 8·7-11·4) in the group that received in the nab-paclitaxel every 3 weeks, 11·1 months (9·9-13·0) in the weekly nab-paclitaxel group, and 10·9 months (9·4-11·8) in the weekly solvent-based paclitaxel group. Weekly nab-paclitaxel was non-inferior to weekly solvent-based paclitaxel (hazard ratio 0·97, 97·5% CI 0·76-1·23; non-inferiority one-sided p=0·0085), whereas nab-paclitaxel every 3 weeks was not non-inferior to solvent-based paclitaxel (1·06, 95% CI 0·87-1·31; non-inferiority one-sided p=0·062). The main grade 3 or worse adverse drug reactions were neutropenia (158 [65%] of 244 patients in the group that received nab-paclitaxel every 3 weeks vs 99 [41%] of 241 patients in the weekly nab-paclitaxel group vs 71 [29%] of 243 patients in the weekly solvent-based paclitaxel group), peripheral sensory neuropathy (49 [20%] vs six [2%] vs six [2%]), and febrile neutropenia (30 [12%] vs seven [3%] vs two [1%]). Hypersensitivity reactions were less frequent with nab-paclitaxel every 3 weeks (two [1%] patients) and weekly nab-paclitaxel (three [1%] patients) than with weekly solvent-based paclitaxel (13 [5%] patients). Four treatment-related deaths were reported overall (pneumonia in one patient in the group that received nab-paclitaxel every 3 weeks, febrile neutropenia/pneumonia in one patient, and septic shock in one patient in the weekly nab-paclitaxel group, and respiratory disease/interstitial lung disease in one patient in the weekly solvent-based paclitaxel group). INTERPRETATION: As the trial showed that weekly nab-paclitaxel was non-inferior to weekly solvent-based paclitaxel in terms of overall survival, the advantages of the nab-paclitaxel formulation make it a potential regimen for second-line treatment of gastric cancer. FUNDING: Taiho Pharmaceutical.