Modeled Hepatic/Plasma Exposures of Omeprazole Prescribed Alone in Cytochrome P450 2C19 Poor Metabolizers Are Likely Associated with Hepatic Toxicity Reported in a Japanese Adverse Event Database.

Omeprazole, a gastric acid pump inhibitor, is repeatedly administered and is oxidatively metabolized mainly by polymorphic cytochrome P450 2C19. The prescribed dosage of omeprazole was discontinued or reduced in 47 of the 135 patients who received omeprazole alone in this survey, as recorded in the Japanese Adverse Drug Event Report database. The days to onset of omeprazole-related disorders were 3-4 d (median) and 16 d for intravenous 20-40 mg and oral 20 mg daily doses, respectively, in 34 patients for whom relevant data were available. The maximum plasma concentration of omeprazole was pharmacokinetically modeled after a single oral 40-mg dose in P450 2C19-defective poor metabolizers and was 2.4-fold higher than that in extensive metabolizers. The modeled area under the hepatic concentration curves of omeprazole in P450 2C19 poor metabolizers after virtual daily 40-mg doses for 7 d was 5.2-fold higher than that in the extensive metabolizers. Omeprazole-induced P450 2C19 (approx. 2-fold), resulting in increased hepatic intrinsic clearance in repeated doses, was considered after the second day. Virtual plasma/hepatic exposure estimated using pharmacokinetic modeling in subjects with P450 2C19 poor metabolizers indicated that these exposure levels virtually estimated could be one of causal factors for unexpected hepatic disorders induced by prescribed omeprazole, such as those resulting from drug interactions with repeatedly co-administered medicines.

Modeled Hepatic/Plasma Exposures of Fluvastatin Prescribed Alone in Subjects with Impaired Cytochrome P450 2C9*3 as One of Possible Determinant Factors Likely Associated with Hepatic Toxicity Reported in a Japanese Adverse Event Database.

Fluvastatin is a 3-hydroxy-3-methylglutaryl CoA reductase inhibitor that competitively inhibits human cytochrome P450 (P450) 2C9 in vitro. Drug interactions between a variety of P450 2C9 substrates/inhibitors and fluvastatin can increase the incidence of fluvastatin-related hepatic or skeletal muscle toxicity in vivo. In this survey, the prescribed dosage of fluvastatin was reduced or discontinued in 133 of 164 patients receiving fluvastatin alone, as recorded in the Japanese Adverse Drug Event Report database of spontaneously reported events. The median days to onset of fluvastatin-related disorders were in the range 30-35 d in the 87 patients. Therefore, we aimed to focus on fluvastatin and, using the pharmacokinetic modeling technique, estimated the virtual plasma and hepatic exposures in subjects harboring the impaired CYP2C9*3 allele. The plasma concentrations of fluvastatin modeled after a virtual oral 20-mg dose increased in homozygotes with CYP2C9*3; the area under the plasma concentration curve was 4.9-fold higher than that in Japanese homozygotes for wild-type CYP2C9*1. The modeled hepatic concentrations of fluvastatin in patients with CYP2C9*3/*3 after virtual daily 20-mg doses for 7 d were 31-fold higher than those in subjects with CYP2C9*1/*1. However, heterozygous Chinese patients with CYP2C9*1/*3 reportedly have a limited elevation (1.2-fold) in plasma maximum concentrations. Virtual hepatic/plasma exposures in subjects harboring the impaired CYP2C9*3 allele estimated using pharmacokinetic modeling indicate that such exposure could be a causal factor for hepatic disorders induced by fluvastatin prescribed alone in a manner similar to that for interactions with a variety of co-administered drugs.

Impact of microsampling on toxicological evaluation in rodent safety studies.

Recently, animal welfare has been attracting worldwide attention, and implementation of 3Rs (replacement, reduction, and refinement) is prioritized in every way possible in the drug development. Microsampling, in which small amounts of blood are collected, is attracting attention in this context. ICH S3A Q&A focused on microsampling was published in November 2017 to help accelerate the application of microsampling for toxicokinetic assessment. The increased sensitivity of drug measurement apparatuses such as mass spectrometers has made it possible to measure drug concentrations with small amounts of blood samples. In this review, we summarized the reports on toxicological influence of microsampling in rodents (rats and mice) with or without drug administration or recovery period after blood collection and influences that may arise from differences in the blood sampling site or blood sampling volume. We also summarized some perspectives on further implementation of microsampling in toxicology studies. The use of microsampling in regulatory toxicology studies has gradually increased, although at a lower rate than in discovery studies. Since more animals are used in GLP toxicology studies than in discovery studies, the effect of reducing the number of animals by microsampling is expected to be greater in the toxicology studies. This report aims to promote the application of microsampling to nonclinical studies, as it is beneficial for improving animal welfare and can contribute to the 3Rs.

Characterization of stromal calcifications in odontogenic keratocyst: a multicentric study.

Odontogenic keratocysts (OKCs) are locally aggressive cysts that exhibit typical histopathological features and have a propensity for recurrence. Though histological variations are observed in OKCs, hard tissue formation and metaplastic changes are rare, and the underlying pathogenesis is not well understood. This study aimed to characterize stromal calcifications and analyze their association with odontogenic components in non-syndromic and syndrome-associated cases of OKCs. We analyzed 153 cases of OKCs from healthcare institutes in India and Japan. The epithelial and stromal features were evaluated, and the relationship of calcifications with odontogenic rests was determined. Immunohistochemistry for cytokeratin-19 and special stains including Masson Trichrome and Van Gieson, were used for identification of odontogenic rests and calcifications respectively. Stromal calcifications were observed in 29.41% OKCs. The calcification patterns included irregular dystrophic, dentinoid with linear or calcospherite-type mineralization, and psammoma calcifications. Psammoma and dentinoid calcifications were found in the proximity of cytokeratin-19-positive odontogenic rests or satellite cysts, whereas majority cases with dystrophic calcifications did not exhibit co-localization with stromal odontogenic components. Distinct patterns of calcifications were observed in OKCs. Calcifications found in proximity of the odontogenic rests were possibly indicative of an inductive or host-mediated response.

CRISPR/Cas9-Mediated Induction of Relapse-Specific NT5C2 and PRPS1 Mutations Confers Thiopurine Resistance as a Relapsed Lymphoid Leukemia Model.

6-Mercaptopurine (6-MP) is a key component in maintenance therapy for childhood acute lymphoblastic leukemia (ALL). Recent next-generation sequencing analysis of childhood ALL clarified the emergence of the relapse-specific mutations of the NT5C2 and PRPS1 genes, which are involved in thiopurine metabolism. In this scenario, minor clones of leukemia cells could acquire the 6-MP-resistant phenotype as a result of the NT5C2 or PRPS1 mutation during chemotherapy (including 6-MP treatment) and confer disease relapse after selective expansion. Thus, to establish new therapeutic modalities overcoming 6-MP resistance in relapsed ALL, human leukemia models with NT5C2 and PRPS1 mutations in the intrinsic genes are urgently required. Here, mimicking the initiation process of the above clinical course, we sought to induce two relapse-specific hotspot mutations (R39Q mutation of the NT5C2 gene and S103N mutation of the PRPS1 gene) into a human lymphoid leukemia cell line by homologous recombination (HR) using the CRISPR/Cas9 system. After 6-MP selection of the cells transfected with Cas9 combined with single-guide RNA and donor DNA templates specific for either of those two mutations, we obtained the sublines with the intended NT5C2-R39Q and PRPS1-S103N mutation as a result of HR. Moreover, diverse in-frame small insertion/deletions were also confirmed in the 6-MP-resistant sublines at the target sites of the NT5C2 and PRPS1 genes as a result of nonhomologous end joining. These sublines are useful for molecular pharmacological evaluation of the NT5C2 and PRPS1 gene mutations in the 6-MP sensitivity and development of therapy overcoming the thiopurine resistance of leukemia cells. SIGNIFICANCE STATEMENT: Mimicking the initiation process of relapse-specific mutations of the NT5C2 and PRPS1 genes in childhood acute lymphoblastic leukemia treated with 6-mercaptopurine (6-MP), this study sought to introduce NT5C2-R39Q and PRPS1-S103N mutations into a human lymphoid leukemia cell line by homologous recombination using the CRISPR/Cas9 system. In the resultant 6-MP-resistant sublines, the intended mutations and diverse in-frame small insertions/deletions were confirmed, indicating that the obtained sublines are useful for molecular pharmacological evaluation of the NT5C2 and PRPS1 gene mutations.

The Impact of Pretreatment Esophageal Stenosis on Survival of Esophageal Cancer Patients.

BACKGROUND: Little is known about the survival impacts of pretreatment cancerous stenosis on patients with esophageal carcinoma (EC). METHODS: The clinicopathologic characteristics of patients who underwent surgery for EC between January 2010 and December 2018 were retrospectively reviewed. Esophageal stenosis was defined as present when a thin endoscope could not be passed through the tumor site. The impacts of stenosis on overall survival (OS) and cancer-specific survival (CSS) were evaluated using Cox hazards analysis. RESULTS: Of the 496 EC patients in this study, 51 (10.3 %) had pretreatment esophageal stenosis. Stenosis was associated with lower body mass index (P < 0.001) and higher pStage (P < 0.001). The 3-year OS rate for the patients with stenosis was significantly poorer than for the patients without stenosis (40.2 % vs 69.6 %; hazard ratio [HR], 2.19; P < 0.001). The survival outcomes, especially CSS, for the patients with stenosis were significantly poorer than for the patients without stenosis for both pStage II-III (P = 0.009) and pStage IV (P = 0.006) disease. The OS and CSS curves were well stratified by the presence of stenosis even in early-stage (pStage II) patients (P = 0.04 and P < 0.01, respectively). Multivariable analysis showed esophageal stenosis, pStage III-IV disease, and non-curative resection to be independently associated with poor OS (HR, 1.61; P = 0.02) and poor CSS (HR,1.67; P = 0.02). Higher pStage was an independent predictor of poor CSS for patients without stenosis, but not for those with stenosis. CONCLUSIONS: Esophageal carcinoma patients with pretreatment stenosis had significantly poorer survival outcomes, especially poorer CSS, than those without stenosis in both early- and advanced-stage diseases.

Pharmacokinetic Models Scaled-up from Humanized-liver Mouse Data Can Account for Drug Monitoring Results of Atomoxetine and Its 4-Hydroxylated and N-Demethylated Metabolites i n Pediatric Patients Genotyped for Cytochrome P450 2D6.

Atomoxetine is a cytochrome P450 (P450) 2D6 probe substrate and an approved medicine for attention-deficit/hyperactivity disorder. In this humanized-liver mouse study, interactions between atomoxetine and the P450 2D6 probe drug paroxetine were observed. Human physiologically based pharmacokinetic (PBPK) models were established by scaling up humanized-liver mouse data obtained in the absence or presence of paroxetine. These models could explain the drug monitoring results of atomoxetine and its primary 4-hydroxylated and N-demethylated metabolites in Japanese children aged 8-14 years and could be used to help establish the correct dosage and for the evaluation of clinical outcomes. The results of simple PBPK models (using input parameters that reflected the subjects' small body size and normal or reduced P450 2D6-dependent clearance) were in general agreement with one-point measured plasma concentrations of atomoxetine and its 4-hydroxylated and N-demethylated metabolites in 13 pediatric participants. Unexpectedly high hepatic exposure, possibly in intermediate-metabolizer patients harboring CYP2D6*10 or 2D6*36 alleles, might in part explain the adverse effects of atomoxetine prescribed alone recorded in a Japanese adverse-event database. The steady-state, one-point drug monitoring data from the participants indicated extensive biotransformation of atomoxetine to 4-hydroxyatomoxetine under individually prescribed doses of atomoxetine. These results also suggest that a relatively narrow range of 4-hydroxyatomoxetine and N-desmethylatomoxetine concentration ratios in spot urine and/or plasma samples from pediatric patients could be a simple semiquantitative determinant factor for P450 2D6 intermediate metabolizers, compared with the wide range of concentrations of the two primary metabolites and substrate in extensive metabolizers. Significance Statement Validated simple pharmacokinetic models are able to predict steady-state plasma concentrations of the approved medicine atomoxetine and its primary metabolites in the majority of pediatric patients. The package insert advises careful dose escalation, especially for poor metabolizers; however, no simple way exists to determine P450 2D6 phenotypes. A relatively narrow range ratio of 4-hydroxyatomoxetine and N-desmethylatomoxetine in spot urine/plasma samples could be a simple semi-quantitative determinant factor for P450 2D6 intermediate metabolizers to optimize or confirm the correct dosage.

Significant association between HLA-B*35:01 and onset of drug-induced liver injury caused by Kampo medicines in Japanese patients.

AIM: Drug-induced liver injury (DILI) is a severe and life-threatening immune-mediated adverse effect, occurring rarely among treated patients. We examined genomic biomarkers in the Japanese population that predict the onset of DILI after using a certain class of drugs, such as Kampo products (Japanese traditional medicines). METHODS: A total of 287 patients diagnosed as DILI by hepatology specialists were recruited after written informed consent was obtained. A genome-wide association analysis and human leukocyte antigen (HLA) typing in four digits were performed. RESULTS: We found a significant association (p = 9.41 × 10-10 ) of rs146644517 (G > A) with Kampo product-related DILI. As this polymorphism is located in the HLA region, we evaluated the association of HLA types and found that 12 (63.2%) of 19 Kampo-DILI patients contained HLA-B*35:01, whereas only 15.2% were positive for this HLA among healthy volunteers. The odds ratio was 9.56 (95% confidence interval 3.75-24.46; p = 2.98 × 10-6 , corrected p = 4.17 × 10-5 ), and it increased to 13.55 compared with the DILI patients not exposed to Kampo products. The individual crude drug components in the Kampo products, including Scutellaria root (ougon in Japanese), rhubarb (daiou), Gardenia fruit (sanshishi), and Glycyrrhiza (kanzou), were significantly associated with HLA-B*35:01. CONCLUSIONS: HLA-B*35:01 is a genetic risk factor and a potential predictive biomarker for Kampo-induced DILI in the Japanese population.

Development of Novel Mass Spectrum-Based Assay for Simultaneous Detection of 36 Variants in the 14 Pharmacogenetic Genes for the Japanese Population.

Pharmacogenetics (PGx) enhances personalized care, often reducing medical costs, and improving patients' QOL. Unlike single variant analysis, multiplex PGx panel tests can result in applying comprehensive PGx-guided medication to maximize drug efficacy and minimize adverse reactions. Among PGx genes, drug-metabolizing enzymes and drug transporters have significant roles in the efficacy and safety of various pharmacotherapies. In this study, a genotyping panel has been developed for the Japanese population called PGx_JPN panel comprising 36 variants in 14 genes for drug-metabolizing enzymes and drug transporters using a mass spectrometry-based genotyping method, in which all the variants could be analyzed in two wells for multiplex analysis. The verification test exhibited good concordance with the results analyzed using the other standard genotyping methods (microarray, TaqMan assay, or another mass spectrometry-based commercial kit). However, copy number variations such as CYP2D6*5 could not apply to this system. In this study, we demonstrated that the mass spectrometry-based multiplex method could be useful for in the simultaneous genotyping of more than 30 variants, which are essential among the Japanese population in two wells, except for copy number variations. Further study is needed to assess our panel to demonstrate the clinical use of pharmacogenomics for precision medicine in the Japanese population.

Plasma and Hepatic Exposures of Celecoxib and Diclofenac Prescribed Alone in Patients with Cytochrome P450 2C9*3 Modeled after Virtual Oral Administrations and Likely Associated with Adverse Drug Events Reported in a Japanese Database.

The impacts of polymorphic cytochrome P450 (P450 or CYP) 2C9 on drug interactions and the pharmacokinetics of cyclooxygenase inhibitors have attracted considerable attention. In this survey, the prescribed dosage was reduced or discontinued in 150 and 56 patients, respectively, receiving celecoxib and diclofenac prescribed alone, as recorded in a Japanese database of adverse drug events. Among the factors underlying adverse events, intrinsic drug clearance rates may be a contributing factor. The pharmacokinetically modeled plasma concentrations of celecoxib after an oral 200-mg dose increased in CYP2C9*3 homozygotes: the area under the plasma concentration curve was 4.7-fold higher than that in CYP2C9*1 homozygotes. In patients with CYP2C9*3/*3, the virtual hepatic concentrations of diclofenac after three daily 25-mg doses for a week were 11-fold higher than the plasma concentrations in subjects with CYP2C9*1/*1. The in vivo and in vitro fractions of the victim drug metabolized by a specific polymorphic P450 form is an important determining factor for estimating drug-drug interactions. Virtual hepatic and plasma exposures estimated by pharmacokinetic modeling in patients harboring the impaired CYP2C9*3 allele could represent a causal factor for adverse events induced by celecoxib or diclofenac in a manner similar to that for drug interactions.

Prominence of NUDT15 genetic variation associated with 6-mercaptopurine tolerance in a genome-wide association study of Japanese children with acute lymphoblastic leukaemia.

Inherited genetic variation is associated with 6-mercaptopurine (6-MP) dose reduction and frequent toxicities induced by 6-MP. However, the tolerable dose for 6-MP is not fully predicted by the known variation in NUDT15 and TPMT among Asian children with acute lymphoblastic leukaemia (ALL). We performed a genome-wide association study (GWAS) related to 6-MP dose among Japanese children with ALL. This GWAS comprised 224 patients previously enrolled in Tokyo Children's Cancer Study Group clinical studies with replication attempted in 55 patients. Genome-wide single nucleotide polymorphism (SNP) genotypes were evaluated for association with average 6-MP dose during the initial 168 days of maintenance therapy. Possible associations were observed across five gene-coding regions, among which only variants at 13q14.2 were significant and replicated genome-wide (rs116855232, NUDT15, ß = -10.99, p = 3.7 × 10-13 ). Notable findings were observed for variants in AFF3 (rs75364948, p = 2.05 × 10-6 ) and CHST11 (rs1148407, p = 2.09 × 10-6 ), but were not replicated possibly due to small numbers. A previously reported candidate SNP in MTHFR was associated with higher average 6-MP dose (rs1801133, p = 0.045), and FOLH1 (rs12574928) was associated in an evaluation of candidate regions (padjust  = 0.013). This study provides strong evidence that rs116855232 in NUDT15 is the genetic factor predominantly associated with 6-MP tolerable dose in children in Japan.

[Pharmacogenomics in hematological malignancy].

Therapeutic response and drug-induced toxicity have been reported to be associated with genetic variants of drug-metabolizing enzymes and transporters. Recently, new causative variants associated with drug response have been reported by genome-wide association studies (GWASs). Additionally, therapeutic response has been predicted using a model of multiple single-nucleotide polymorphisms. In acute lymphoblastic leukemia (ALL), the genetic variants of NUDT15 associated with therapeutic response to 6-mercaptopurine (6-MP) have been reported by GWASs, and the frequency of NUDT15 variants was higher in Asians. Then, several reports on NUDT15 genetic variants associated with 6-MP-induced toxicities and the tolerable doses and outcomes of 6-MP therapy for ALL have been published in Asian countries. The drugs used in treating hematological malignancies have reported new genetic variants associated with its therapeutic response. However, the association between these genetic variants has not been validated in other populations. Here, we reviewed recent reports on the association between the genetic variants and response to drugs used in treating hematological malignancies, such as 6-MP, cytarabine, methotrexate, and vincristine.

NUDT15 polymorphism and NT5C2 and PRPS1 mutations influence thiopurine sensitivity in acute lymphoblastic leukaemia cells.

In chemotherapy for childhood acute lymphoblastic leukaemia (ALL), maintenance therapy consisting of oral daily mercaptopurine and weekly methotrexate is important. NUDT15 variant genotype is reportedly highly associated with severe myelosuppression during maintenance therapy, particularly in Asian and Hispanic populations. It has also been demonstrated that acquired somatic mutations of the NT5C2 and PRPS1 genes, which are involved in thiopurine metabolism, are detectable in a portion of relapsed childhood ALL. To directly confirm the significance of the NUDT15 variant genotype and NT5C2 and PRPS1 mutations in thiopurine sensitivity of leukaemia cells in the intrinsic genes, we investigated 84 B-cell precursor-ALL (BCP-ALL) cell lines. Three and 14 cell lines had homozygous and heterozygous variant diplotypes of the NUDT15 gene, respectively, while 4 and 2 cell lines that were exclusively established from the samples at relapse had the NT5C2 and PRPS1 mutations, respectively. Both NUDT15 variant genotype and NT5C2 and PRPS1 mutations were significantly associated with DNA-incorporated thioguanine levels after exposure to thioguanine at therapeutic concentration. Considering the continuous exposure during the maintenance therapy, we evaluated in vitro mercaptopurine sensitivity after 7-day exposure. Mercaptopurine concentrations lethal to 50% of the leukaemia cells were comparable to therapeutic serum concentration of mercaptopurine. Both NUDT15 variant genotype and NT5C2 and PRPS1 mutations were significantly associated with mercaptopurine sensitivity in 83 BCP-ALL and 23 T-ALL cell lines. The present study provides direct evidence to support the general principle showing that both inherited genotype and somatically acquired mutation are crucially implicated in the drug sensitivity of leukaemia cells.

Differential effects of mesalazine formulations on thiopurine metabolism through thiopurine S-methyltransferase inhibition.

BACKGROUND AND AIM: Thiopurines are often used in combination with mesalazine for the treatment of ulcerative colitis (UC). Mesalazine formulations are delivered to the digestive tract by various delivery systems and absorbed as 5-aminosalicylic acid (5-ASA). 5-ASA is known to inhibit thiopurine S-methyltransferase (TPMT) activity and to affect thiopurine metabolism. There have been no studies comparing TPMT inhibition by multimatrix mesalazine (MMX) with other formulations. We investigated the difference in TPMT inhibition by different mesalazine formulations and prospectively confirmed the clinical relevance. METHODS: Plasma concentrations of 5-ASA, N-acetyl-5-aminosalicylic acid (N-Ac-5-ASA), and TPMT activities were measured in UC patients receiving various mesalazine formulations (time-dependent or pH-dependent mesalazine or MMX) as monotherapy. Patients already on both time-dependent or pH-dependent mesalazine and thiopurines switched their mesalazine to MMX, examining 6-thioguanine nucleotide (6-TGN) and 6-methylmercaptopurine (6-MMP) 0 and 8 weeks after switching. Clinical relapse after switching was also monitored for 24 weeks. RESULTS: Plasma 5-ASA and N-Ac-5-ASA levels were significantly higher in patients receiving time-dependent mesalazine (n = 12) compared with pH-dependent mesalazine (n = 12) and MMX (n = 15), accompanied by greater TPMT inhibition. Prospective switching from time-dependent mesalazine to MMX decreased 6-TGN levels, increased those of 6-MMP, and increased 6-MMP/6-TGN ratios. Furthermore, this resulted in significantly more relapses than switching from pH-dependent mesalazine to MMX. CONCLUSIONS: Time-dependent mesalazine has higher plasma 5-ASA and N-Ac-5-ASA levels and greater TPMT inhibition than MMX. Therefore, switching from time-dependent mesalazine to MMX may lead to an increase of 6-MMP/6-TGN, which may reduce the clinical effectiveness of thiopurines, warranting close monitoring after switch.

Anomalies of the right vertebral vein increasing the difficulty of lymph-node dissection along the right recurrent laryngeal nerve: a single-institution, retrospective study.

BACKGROUND: Radical lymph-node dissection along the recurrent laryngeal nerves (RLN) improves the prognosis of patients with esophageal cancer. The RLN is a landmark for achieving adequate lymph-node dissection. However, the right RLN is sometimes covered by the right vertebral veins (VVs), making it undetectable. We investigated the relationship between this anomaly of the right VVs and the challenges of performing lymphadenectomy along the right RLN. METHODS: Patients with esophageal cancer, who underwent thoracoscopic esophagectomy with radical lymph-node dissection, were registered. The patterns of the right VVs were evaluated by preoperative computed tomography. The time required for identifying the right RLN or completing the lymphadenectomy was determined by reviewing surgical videos. RESULTS: In total, 178 patients were enrolled. Eighty patients (45%) had right VVs passing dorsal to the right subclavian artery (Dorsal group). More time was required to detect the right RLN in these cases (11 vs 9.5 min for the other cases, p = 0.034). In the Dorsal group, there were 15 patients who had specific VV patterns: The right VV converged on the lower portion of the right brachiocephalic vein (BCV), or passed through to the more medial side of the mediastinum. These patients required more time for detecting the right RLN (25 vs 9 min, p < 0.0001) and for completing the lymphadenectomy (41 vs 32 min, p = 0.048) than the other cases. CONCLUSION: The right VVs behind the subclavian artery, joining the lower part of the BCV or passing through the medial side, made it difficult to identify the right RLN and complete the lymphadenectomy.

Tolerability of Erythrocyte Ribavirin Triphosphate Concentrations Depends on the ITPA Genotype.

BACKGROUND: Ribavirin (RBV) is an antiviral drug that is part of the current standard therapy for chronic hepatitis C (CHC). It is enzymatically converted to ribavirin triphosphate (RTP) that inhibits the activity of viral RNA polymerase, thereby preventing viral replication. However, one of its adverse effects includes hemolytic anemia that limits its application. The variant of ITPA (inosine triphosphatase), which dephosphorylates inosine triphosphate to inosine monophosphate, is a protective factor for RBV-induced anemia. RTP is an important metabolite required for ribavirin action. This study evaluated the time-dependent association of RTP concentrations in erythrocytes, RBV-induced toxicity, and virological response to RBV treatment for hepatitis C. METHODS: A total of 28 Japanese patients with CHC were treated with RBV/peg-interferon/simeprevir or RBV/sofosbuvir and were genotyped for ITPA variants (rs1127354 and rs7270101). We measured RTP concentrations in erythrocytes in a total of 76 samples collected at 4, 8, and 12 weeks from the initiation of treatment. RESULTS: The ITPA rs1127354 variant was found in 7 patients. This was associated with significantly higher RTP concentrations in erythrocytes than in the wild-type patients (P < 0.001). Moreover, a significant correlation was observed between RTP concentrations and decline in hemoglobin (Hb) levels from baseline values in ITPA wild type and rs1127354 variant 12 weeks after treatment initiation (P < 0.01; r = -0.618 and -0.967, respectively). Multiple regression analysis revealed that ITPA genotype and erythrocyte RTP concentrations were major factors associated with reduced Hb levels in RBV therapy for CHC. However, we did not find any association between erythrocyte concentrations and virological response. CONCLUSIONS: The increased tolerability to RTP concentrations in erythrocytes in the ITPA variant rs1127354 plays a role in preventing RBV-induced severe anemia in this ITPA variant.

Phase II feasibility study of preoperative concurrent chemoradiotherapy with cisplatin plus 5-fluorouracil and elective lymph node irradiation for clinical stage II/III esophageal squamous cell carcinoma.

BACKGROUND: Preoperative chemoradiotherapy (CRT) is a standard treatment for stage II/III esophageal cancer. Preoperative chemotherapy is also considered a standard treatment for stage II/III esophageal squamous cell carcinoma (ESCC) in patients who undergo radical lymph node dissection. We conducted a feasibility study of preoperative CRT with cisplatin plus 5-fluorouracil (CF) and elective lymph node irradiation followed by esophagectomy with radical lymph node dissection in patients with stage II/III ESCC. METHODS: Patients with clinical stage II/III, excluding T4, ESCC (International Union Against Cancer TNM classification system, 6th edition) were eligible. Chemotherapy comprised two courses of CF infusion repeated after 4-weeks. Radiation therapy was concurrently administered to the primary tumor, metastatic lymph nodes, and regional lymph nodes at a dose of 41.4 Gy. After the completion of CRT, transthoracic esophagectomy with 2-3 fields lymphadenectomy was performed. The primary endpoint was the completion rate of protocol treatment with R0 resection. RESULTS: Thirty-one eligible patients were enrolled. During CRT, the most common grade 3 or 4 toxicities were leukopenia (65%), neutropenia (65%), anemia (13%), thrombocytopenia (13%), febrile neutropenia (13%), anorexia (16%), esophagitis (16%) and hyponatremia (16%). Thirty patients (96.8%) underwent surgery. One patient received palliative chemotherapy because of appearance of lung metastasis during CRT. The completion rate of protocol treatment was 93.5% (29/31). There was one treatment-related death after surgery. Pathological complete response was achieved in 42% (13/30). CONCLUSION: Preoperative CRT with CF and elective lymph node irradiation showed an acceptable toxicity and promising activity especially in ESCC.

Association of Epithelial Atypia With Recurrence After Surgical Excision in Conjunctival Papilloma.

PURPOSE: To investigate the association between recurrence of conjunctival papillomas and presence of atypical epithelial changes in patients undergoing surgical excision for conjunctival papilloma. METHODS: We retrospectively reviewed 1,195 ophthalmic pathology specimens from 2004 to 2014 at Ichikawa General Hospital. Pathologic specimens of 5 patients with a final diagnosis of "conjunctival papilloma" were stained with hematoxylin-eosin, Ki 67, p53, human papillomavirus (HPV) 16 and 18 antibodies. RESULTS: Of 1,195 patients, 5 patients (4 men, 1 woman; age range: 27∼57 years, mean age: 38.4 years) had a diagnosis of conjunctival papilloma, which constituted to 0.42% of the pathologic diagnosis made for the ophthalmology specimens. All specimens displayed multiple fronds of thickened conjunctival epithelium that enclosed cores of vascularized connective tissues. Three patients with recurrence after surgical excision demonstrated moderate to severe epithelial atypia, who also showed higher staining with Ki67 and p53 compared with patients with no recurrence. HPV16 and 18 antibodies staining did not appear to relate to recurrences. CONCLUSIONS: Conjunctival papillomas with higher positive staining for Ki67 and p53 seem to have a higher risk of recurrence even after complete surgical excision and necessitate careful follow-up.