Safety Profile and Effectiveness of Rivaroxaban for Patients With Venous Thromboembolism in Japan - Results From Post-Marketing Surveillance (XASSENT)

BACKGROUND

The incidence of venous thromboembolism (VTE; pulmonary embolism [PE] and/or deep vein thrombosis [DVT]) in Japan is increasing, but relatively small numbers of patients from Japan have been included in studies investigating rivaroxaban (a direct factor Xa inhibitor) for the treatment of VTE and preventing its recurrence.Methods and Results: An open-label, prospective, observational study (XASSENT [NCT02558465]) investigated the safety profile and effectiveness of rivaroxaban for ≤2 years in the treatment of VTE and prevention of its recurrence in Japanese clinical practice. Primary outcomes were major bleeding and symptomatic recurrent VTE. Statistical analyses were exploratory and descriptive. Overall, 2,540 patients were enrolled (safety analysis population [SAP], n=2,387; effectiveness analysis population [EAP], n=2,386). In the SAP, >80% of patients received the approved rivaroxaban dose, the mean (standard deviation) age was 66.6 (15.0) years, ≈74% were >50 kg, and 43% had a creatinine clearance ≥80 mL/min. PE+DVT, PE only, and DVT only were reported in 42%, 8%, and 50% of patients, respectively, and active cancer in 17% of patients. Major bleeding was reported in 69 patients (2.89%; 3.60%/patient-year; SAP) and symptomatic PE/DVT recurrence in 26 patients (1.09%; 1.36%/patient-year; EAP) during the treatment period.

CONCLUSIONS

XASSENT provided information on the expected proportions of bleeding and VTE recurrence during rivaroxaban treatment in Japanese clinical practice; no new concerns of safety or effectiveness were found.

Effectiveness and safety of sorafenib for renal cell, hepatocellular and thyroid carcinoma: pooled analysis in patients with renal impairment

PURPOSE

Sorafenib is an oral multikinase inhibitor with regulatory approval in advanced renal cell carcinoma (RCC), hepatocellular carcinoma (HCC) and refractory differentiated thyroid carcinoma (DTC). Vascular endothelial growth factor receptor (VEGFR) inhibitors like sorafenib may cause proteinuria. This study aimed to analyze the effectiveness and safety of sorafenib in RCC, HCC and DTC patients with chronic kidney disease (CKD).

METHODS

This retrospective study analyzed integrated data from prospective post-marketing surveillance studies for advanced RCC, HCC and DTC. Background factors considered to affect patients' prognosis were balanced by propensity score matching using eGFR cut-off values of 60 mL/min/1.73 m2.

RESULTS

In the combined matched population (N = 2430), sorafenib was equally effective in patients with lower and higher eGFR values. Sorafenib had an overall response rate (ORR: complete + partial responses) of 18.9% and a disease control rate (DCR: complete + partial responses + stable disease) of 67.0%. There were no significant differences between lower and higher eGFR groups for response rates. Renal function was maintained throughout the 12-month study period in the combined population and in each indication. Adverse events (AEs) and serious AEs were reported in 91.6% and 58.2% of propensity score-matched patients, and with no significant differences between lower and higher eGFR groups.

CONCLUSION

The effectiveness and safety of sorafenib were similar in patients with eGFR < 60 and ≥ 60 mL/min/1.73 m2 during the 12-month observation period, and without impairing renal function.

Impact of three major risk factors on clinical outcomes in patients with nonvalvular atrial fibrillation receiving rivaroxaban: Sub‐analysis from the XAPASS study

Background

Methods

Results

Conclusions

Outcomes of sorafenib treatment of advanced renal cell carcinoma according to International Metastatic Renal Cell Carcinoma Data Consortium risk criteria: analysis of Japanese real-world data from postmarketing all-patient surveillance of sorafenib

Aim: To assess sorafenib survival outcomes in renal cell carcinoma patients using standard International Metastatic Renal Cell Carcinoma Data Consortium (IMDC) risk criteria. Patients & methods: The authors restratified a real-world cohort of 3255 advanced renal cell carcinoma patients, obtained from Japanese sorafenib postmarketing surveillance, to assess survival outcomes using IMDC criteria; intermediate risk was subdivided into Int-1 and Int-2 (one and two risk factors, respectively). Results: Overall, 2225 (68%) IMDC-evaluable patients were reclassified as favorable (17%), intermediate (62%) and poor (21%) risk, with median progression-free survival of 10.4, 8.1 and 3.4 months, respectively. Int-1 (36%) and Int-2 (26%) subgroups had median progression-free survival of 10.1 and 6.0 months, respectively. Sorafenib had acceptable safety/tolerability. Conclusion: Sorafenib effectiveness was promising for IMDC intermediate risk, particularly Int-1, warranting further investigation.

Design and Baseline Data for a Prospective Observational Study of Rivaroxaban in Patients with Venous Thromboembolism in Japan (XASSENT)

Background  The efficacy and safety of rivaroxaban have been demonstrated in phase 3 trials of patients with venous thromboembolism (VTE; pulmonary embolism [PE] and deep vein thrombosis [DVT]). Data regarding rivaroxaban treatment of VTE in routine Japanese clinical practice remain limited.

Objectives  XASSENT will evaluate rivaroxaban treatment of VTE in real-world Japanese clinical practice. We report the study design and baseline patient characteristics.

Methods  XASSENT (NCT02558465) is an open-label, prospective observational, post-marketing surveillance cohort study in patients receiving rivaroxaban treatment for VTE. Enrolment took place between November 2015 and March 2018. XASSENT will follow patients for up to 2 years. Primary outcome variables: major bleeding and symptomatic recurrent VTE. Statistical analyses are exploratory and descriptive.

Results  Baseline patient characteristics at June 2020 ( n  = 2,299) are presented (58.2% female; mean age 66.7 years; mean weight 60.9 kg). The population encompasses patients with wide-ranging characteristics including older age, low weight, and renal dysfunction. Most participants (67.6%) had a history of VTE risk factors at baseline. Half of the population (50.4%) had DVT only; 41.4% had DVT with PE; 8.2% had PE only. Overall, 68.4% were inpatients and 77.1% had symptomatic VTE. Rivaroxaban was prescribed for initial treatment in 84.6% of patients and maintenance treatment in 15.4%. Most were prescribed the approved dose of rivaroxaban for initial (30 mg daily; 84.4%) or maintenance (15 mg daily; 81.9%) treatment of VTE in Japan. The most common reason for selecting non-recommended dose was ‘elderly’.

Conclusions  Results from XASSENT will complement phase 3 trial data and inform clinical practice.

[Exploratory Analysis Results from Post-marketing Surveillance Study of Radium-223 in Japanese Patients with Castration-resistant Prostate Cancer and Bone Metastases: Subgroup Analysis by Age]

OBJECTIVE

To perform an exploratory analysis on the safety and effectiveness of radium-223 (Ra-223) by patient baseline age, using the results of a post-marketing surveillance study of Ra-223 in castration-resistant prostate cancer patients with bone metastasis in Japan.

METHOD

The safety analysis population of 296 patients was stratified into two groups based on age (<75 and ≥ 75 years-old [yo]), and their characteristics, drugrelated treatment-emergent adverse events (TEAEs), and clinical laboratory values were evaluated. Additionally, these endpoints were evaluated in patients aged ≥ 80 yo.

RESULTS

There were 148 patients in each of the <75-yo and ≥ 75-yo age groups, and 69 patients in the ≥ 80-yo age group. The characteristics of patients in the <75-yo group were suggestive of more aggressive disease at diagnosis of prostate cancer and a greater proportion of patients had prior chemotherapy compared with patients in the ≥ 75-yo age group. The incidences of overall drugrelated TEAEs and drug-related hematological TEAEs were slightly higher in the <75-yo age group; however, there was little difference in the incidences of drug-related TEAEs leading to drug discontinuation (1.4-4.1%) between patient groups. Changes in total alkaline phosphatase and prostate-specific antigen values were similar in all groups.

CONCLUSIONS

Ra-223 therapy seemed tolerable regardless of age in real-world practice in Japan. Especially, there were no new safety concerns of Ra-223 in elderly patients.

Real-world safety and effectiveness of rivaroxaban using Japan-specific dosage during long-term follow-up in patients with atrial fibrillation: XAPASS

Background

The Xarelto Post-Authorization Safety and Effectiveness Study in Japanese Patients with Atrial Fibrillation (XAPASS) was designed to investigate safety and effectiveness during long-term follow-up of rivaroxaban treatment, using reduced doses compared with other global regions, in Japanese patients with non-valvular atrial fibrillation in real-world clinical practice.

Methods

In this prospective, open-label, single-arm, observational study, 11,308 patients with non-valvular atrial fibrillation newly prescribed rivaroxaban (15/10 mg once daily) at 1416 sites across Japan were enrolled and followed for a mean of 2.5 years.

Results

In total, 10,664 and 10,628 patients were included in the safety and effectiveness analyses, respectively. In the safety population, mean (standard deviation) age was 73.1 (9.8) years and Congestive heart failure, Hypertension, Age ≥75 years, Diabetes mellitus, previous Stroke/TIA (2 points) (CHADS₂) score was 2.2 (1.3). Incidences (95% confidence intervals) of any and major bleeding were 3.77 (3.53–4.01) and 1.16 (1.03–1.29) events per 100 patient-years, respectively. Age ≥75 years, creatinine clearance <50 mL/min, diabetes mellitus, and vascular disease were independently associated with incidence of major bleeding. The primary composite effectiveness outcome of stroke, non-central nervous system systemic embolism, and myocardial infarction occurred at an incidence (95% confidence interval) of 1.32 (1.18–1.46) events per 100 patient-years. Age ≥75 years, hypertension, prior ischemic stroke/transient ischemic attack, and concomitant use of antiplatelets were independently associated with incidence of the composite outcome of stroke, non-central nervous system systemic embolism, and myocardial infarction.

Conclusion

In the XAPASS, a large-scale study involving a broad range of patients with non-valvular atrial fibrillation newly prescribed rivaroxaban using Japan-specific dosage in real-world clinical practice, no unexpected safety or effectiveness concerns were detected during up to 5 years of follow-up.

Real-world safety and effectiveness of radium-223 in Japanese patients with castration-resistant prostate cancer (CRPC) and bone metastasis: exploratory analysis, based on the results of post-marketing surveillance, according to prior chemotherapy status and in patients without concomitant use of second-generation androgen-receptor axis-targeted agents

BACKGROUND

Based on results from Japanese post-marketing surveillance, exploratory analyses were performed to investigate real-world outcomes of radium-223 for metastatic CRPC (mCRPC) according to patient characteristics.

METHODS

This non-interventional, prospective study enrolled mCRPC patients selected for radium-223 treatment in clinical practice. Six-month safety and effectiveness were evaluated in subgroups who had/had not received prior chemotherapy (prior-chemo/no prior-chemo groups), and a subgroup who had not received concomitant androgen-receptor axis-targeted agents (ARATs).

RESULTS

In the overall population (n = 296), the prior-chemo group (n = 126) tended to have more bone metastases, more analgesic use, and higher prostate-specific antigen values than the no prior-chemo group (n = 170). Incidences of treatment-emergent adverse events (TEAEs), drug-related TEAEs, and ≥ grade 3 drug-related hematological TEAEs were 47% vs. 53%, 25% vs. 29%, and 4% vs. 7% in the no prior-chemo and prior-chemo groups, respectively. Incidences of TEAEs (61%), drug-related TEAEs (36%), and ≥ grade 3 drug-related hematological events (12%) were numerically higher in 33 patients who had received two lines of prior chemotherapy. Multivariate analysis showed that two lines of prior chemotherapy, and hemoglobin, platelet, and lactate dehydrogenase values were baseline factors significantly related to ≥ grade 2 platelet count decreased. Safety and effectiveness in patients without concomitant ARATs (n = 201) were similar to those in the overall population.

CONCLUSION

In a real-life setting, radium-223 was well tolerated irrespective of prior chemotherapy, but relatively higher incidences of TEAEs and hematotoxicities were suggested in patients with two lines of prior chemotherapy, possibly reflecting more advanced disease. Radium-223 safety and effectiveness in patients without concomitant ARATs were favorable.

Long-term outcomes of Japan-specific dosage of rivaroxaban in high-risk patients with non-valvular atrial fibrillation: analysis from the XAPASS

Background

XAPASS is a real-world, prospective, single-arm, observational study conducted as a post-marketing surveillance mandated by the health authority in Japan. Nowadays, direct oral anticoagulant therapy using factor Xa or thrombin inhibitor has been the standard of care for patients with non-valvular atrial fibrillation (NVAF) to prevent ischemic stroke. However, the clinical impact of reduced dosage (approved dose of 15 or 10 mg once daily in Japan is relatively reduced compared to global dosage) factor Xa inhibitor rivaroxaban in high-risk patients remains unclear.

Purpose

The present sub-analysis of XAPASS was carried out to assess long-term safety and effectiveness of reduced-dose rivaroxaban in high-risk NVAF patients for bleeding and thromboembolism.

Methods

All patients with NVAF who were newly started on rivaroxaban were eligible for surveillance. The principal safety outcome was a composite of major and non-major bleeding events, and the primary effectiveness outcome was a composite of ischaemic stroke, haemorrhagic stroke, non-central nervous system systemic embolism (non-CNS SE), and myocardial infarction (MI). In this present sub-analysis, high-risk patients were defined as those who had two of the following three risk factors: elderly (≥75 years old), low body weight (≤50 kg), and renal impairment (CrCl &lt;50 mL/min).

Results

In total, 11,308 patients were enrolled between April 2012 and June 2014 from 1,419 hospitals, and overall data were analysed from 10,664 patients from whom data were collected. Among them, 3,694 patients matched the criteria for the high-risk patients defined in this sub-analysis, and 6,970 patients did not match the criteria (non-high-risk patients). The mean treatment duration was 791±673 days in the high-risk patients and 944±709 days in the non-high-risk patients. Mean patient age was 80.9±5.5 years and 69.0±9.0 years at baseline, respectively. Mean CHADS2 score was 2.8 and 1.8, and CHA2DS2-VASc score was 4.4 and 2.9, respectively. The rates of CHADS2 component comorbidities were lower in the non-high-risk patients except for diabetes mellitus. The incidence rates of any bleeding, major bleeding, and the primary effectiveness outcomes were 4.8, 1.6, and 2.1%/patient-year in the high-risk patients. The incidence rates of these clinical events in the non-high-risk patients were 3.3, 0.9, and 1.0%/patient-year, respectively.

Conclusions

Incidence rates of long-term bleeding and thromboembolism were higher in the high-risk patients than in the non-high-risk patients. However, the rates of these outcomes using the Japan-specific reduced dose were not so high. Furthermore, the balance between safety and effectiveness outcomes was within an acceptable range. The present study provides useful information for physicians to stratify high-risk patients using the reduced dose in daily clinical practice.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Bayer Yakuhin Ltd.

Real-world use of sorafenib for advanced renal cell carcinoma patients with cardiovascular disease: nationwide survey in Japan

OBJECTIVES

To assess whether the clinical outcome of advanced/metastatic renal cell carcinoma (mRCC) treated with sorafenib, in real-world conditions, differs in patients with cardiovascular disease (CVD).

METHODS

mRCC patients (n = 2256 before matching) were matched by propensity score into CVD (n = 560) and non-CVD groups (n = 560), followed by safety and effectiveness analyzes.

RESULTS

After matching, patients' features used for matching were balanced between the CVD and non-CVD groups, except for age (p = 0.0049). Renal comorbidity occurred more frequently in the CVD group. Exposure to sorafenib and objective response rate (25.4% [CVD], 28.5% [non-CVD]) were comparable in both groups. Median progression-free survival (PFS; 7.1 months, 95% CI: 6.4-8.6 [CVD]; 6.7 months, 6.3-8.3 [non-CVD]), and hazard ratios for PFS (0.954, 0.821-1.108) and overall survival (0.889, 0.683-1.156), were similar in the matched population. The incidences of adverse drug reactions (ADR, ≥10%) were generally similar between groups, although hypertension (42.1% vs 34.5%), diarrhea (26.3% vs 19.6%), decreased appetite (11.3% vs 7.5%), and non-serious and serious renal failure/dysfunction (3.6% vs 1.4% and 1.8% vs 0.4%), occurred more frequently in the CVD group.

CONCLUSION

This analyzes suggests that sorafenib has clinical benefit for mRCC patients regardless of baseline CVD. Serious ADRs increased for renal dysfunction.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov identifier is NCT01411423.

Impact of body mass index on real-world outcomes of rivaroxaban treatment in Japanese patients with non-valvular atrial fibrillation

This sub-analysis of the XAPASS, a prospective, single-arm, observational study, aimed to evaluate relationships between body mass index (BMI) and safety (major bleeding and all-cause mortality) and effectiveness [stroke/non-central nervous system (non-CNS) systemic embolism (SE)/myocardial infarction (MI)] outcomes in Japanese patients with non-valvular atrial fibrillation (NVAF) receiving rivaroxaban. Patients were categorized according to BMI (kg/m²) as underweight (< 18.5), normal weight (18.5 to < 25), overweight (25 to < 30), or obese (≥ 30). In total, 9578 patients with NVAF completed the 1-year follow-up and were evaluated; of these, 7618 patients had baseline BMI data. Overall, 542 (5.7%), 4410 (46.0%), 2167 (22.6%), and 499 (5.2%) patients were underweight, normal weight, overweight, and obese, respectively. Multivariable Cox regression analysis demonstrated that none of the BMI categories were independent predictors of major bleeding whereas being underweight was independently associated with increased all-cause mortality [hazard ratio (HR) 3.56, 95% confidence interval (CI) 2.40–5.26, p < 0.001]. The incidence of stroke/non-CNS SE/MI was higher in patients who were underweight than in those of normal weight (HR 2.11, 95% CI 1.20–3.70, p = 0.009). However, in multivariable analyses, being underweight was not identified as an independent predictor of stroke/non-CNS SE/MI (HR 1.64, 95% CI 0.90–2.99, p = 0.104). In conclusion, the high incidence of thromboembolic events and all-cause mortality in patients who were underweight highlights that thorough evaluation of disease status and comorbidities may be required in this population.

Outcomes associated with under-dosing of rivaroxaban for management of non-valvular atrial fibrillation in real-world Japanese clinical settings

The approved dose of oral anticoagulant rivaroxaban for patients with non-valvular atrial fibrillation (NVAF) in Japan is 15 mg once daily (od) in patients whose creatinine clearance is ≥ 50 mL/min, but recent real-world studies have demonstrated that these patients often received less than the recommended dose due to bleeding concerns. The effect of under-dosing on safety and effectiveness outcomes remains unclear. We used 1-year follow-up data from the XAPASS, a real-world Japanese prospective, single-arm, observational study. Of the 11,308 patients, 6521 patients who completed a 1-year follow-up and had a creatinine clearance ≥ 50 mL/min were included in this sub-analysis. Primary endpoints were any bleeding and a composite of stroke/non-central nervous system systemic embolism (non-CNS SE)/myocardial infarction (MI). Among the 6521 patients, 4185 (64.2%; mean CHADS₂ score: 1.8) received the 15 mg od (recommended dose), whereas 2336 (35.8%; mean CHADS₂ score: 2.3) received 10 mg od (under-dose). After adjusting for patient characteristics by propensity scoring and inverse probability of treatment weighting, incidence rates of major bleeding were comparable between under-dosed patients and patients who received the recommended dose (1.34 vs. 1.63 events/100 patient-years, p = 0.197), although the incidence rates of stroke/non-CNS SE/MI were higher in under-dosed patients than in those who received the recommended dose (2.15 vs. 1.48 events/100 patient-years, p = 0.009). In Japanese clinical practice, some NVAF patients receive rivaroxaban doses inconsistent with the recommendation. Considering the total clinical benefit, the recommended dose may be preferable in terms of balance of safety and effectiveness.Clinicaltrials.gov NCT01582737.

Real-world outcomes of rivaroxaban treatment in elderly Japanese patients with nonvalvular atrial fibrillation

Direct oral anticoagulants (DOACs), such as rivaroxaban, reduce the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation (NVAF). However, it is still unclear whether the stroke reduction benefit outweighs the bleeding risk in elderly Japanese patients with NVAF. The Xarelto Post-Authorization Safety and Effectiveness Study in Japanese Patients with Atrial Fibrillation (XAPASS) was a real-world, prospective observational, post-marketing surveillance study on the safety and effectiveness of rivaroxaban in Japanese clinical practice. This sub-analysis evaluated the clinical outcomes of elderly patients aged ≥ 75 years. At the 1-year follow-up, there were 4,685 (48.91%) and 4,893 (51.09%) patients aged ≥ 75 and < 75 years, respectively. Safety and effectiveness outcomes were compared between patients aged ≥ 75 years and those aged < 75 years, and among 3 elderly sub-populations (age ranges: 75-79, 80-84, and ≥ 85 years). Patients aged ≥ 75 years had higher rates of major bleeding [2.22 vs. 1.35 events per 100 patient-years, hazard ratio (HR) 1.63, 95% confidence interval (CI) 1.17-2.28] and composite of stroke (ischemic or hemorrhagic)/non-central nervous system (non-CNS) systemic embolism (SE)/myocardial infarction (MI) (2.41 vs. 1.21 events per 100 patient-years, HR 1.97, 95% CI 1.40-2.77) compared to patients aged < 75 years. Intracranial hemorrhage rates were < 1 event per 100 patient-years in both groups (0.85 vs. 0.59 events per 100 patient-years, HR 1.43, 95% CI 0.85-2.40). Kaplan-Meier curves of major bleeding and stroke/non-CNS SE/MI showed that no significant differences of cumulative event rates were identified among the 3 elderly sub-populations. Stepwise Cox regression analyses revealed that creatinine clearance (CrCl) (<50 mL/min), hepatic impairment, and hypertension were specific predictors for major bleeding and no specific predictors were found for stroke/non-CNS SE/MI in patients aged ≥ 75 years. In conclusion, safety and effectiveness event rates were higher in patients aged ≥ 75 years compared with those aged < 75 years, yet, no distinct differences were observed among the 3 elderly sub-populations.

Safety and effectiveness of radium-223 dichloride (Ra-223) in patients with mCRPC in real-world setting: A Japanese post-marketing study (PMS)

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Background: In order to assess safety and effectiveness of Ra-223 in real-world setting, a PMS has been conducted under Japanese regulation for Good Post-marketing Study Practice. Methods: This was a prospective, single-arm, observational study of patients (pts) with mCRPC. The planned sample size was 300. In this primary analysis, clinical outcomes during the 6 month observational period up to 1 month after the last injection of Ra-223 were assessed. An exploratory subgroup analysis was performed according to symptom status at baseline (asymptomatic (AS) or symptomatic (S): WHO's cancer pain ladder 0 or >1). Results: A total of 334 pts were enrolled from Jun 2016 to Nov 2017. As of May 2019, data for 273 pts were available (table). The incidence of drug-related any treatment-emergent adverse events (TEAEs), hematologic TEAEs, and skeletal-related events were 27%, 18%, and 3%, respectively. Fractures were reported in 3 pts, but all were judged not related to Ra-223 by investigators. At the subgroup analysis, baseline characteristics for AS-group seemed more favorable than those in S-group (table). More pts in AS-group completed 6 cycles of Ra-223, and incidence of drug-related TEAEs appeared lower in AS-group compared with S-group. More than 90% of pts did not experience pain progression during 24 weeks, regardless of their symptoms status. Conclusions: During the 6 month observational period, no new safety concerns related to Ra-223 treatment were reported. Asymptomatic patients were more likely to complete treatment and experience fewer TEAEs, possibly reflecting less advanced disease. A follow-up observation up to 3 years is on-going.[Table: see text]

Real-World Outcomes of Rivaroxaban Treatment in Patients with Both Nonvalvular Atrial Fibrillation and a History of Ischemic Stroke/Transient Ischemic Attack

Introduction: Prior stroke is a risk factor for stroke and bleeding during anticoagulation in patients with atrial fibrillation (AF). Although rivaroxaban is widely prescribed to reduce their risk of stroke in patients with nonvalvular AF (NVAF), the real-world evidence on rivaroxaban treatment is limited. We aimed to examine the outcomes of rivaroxaban treatment in NVAF patients with prior ischemic stroke/transient ischemic attack (TIA) by using the data of the Xarelto Post-Authorization Safety and Effectiveness Study in Japanese ­Patients with AF, a prospective, single-arm, observational study. Methods: The clinical outcomes of 9,578 patients who completed the 1-year follow-up were evaluated. Safety and effectiveness outcomes were compared between patients with and without prior ischemic stroke/TIA. Results: Among the patients, 2,153 (22.5%) had prior ischemic stroke/TIA. They were significantly older and had lower body weight, lower creatinine clearance, higher CHADS2, CHA2DS2-VASc, and modified HAS-BLED scores as compared to those without prior ischemic stroke/TIA. Any bleeding (9.1 vs. 7.2 events per 100 patient-years), major bleeding (2.3 vs. 1.6 events per 100 patient-years), and stroke/non-central nervous system systemic embolism/myocardial infarction (3.4 vs. 1.3 events per 100 patient-years) were more frequent in patients with prior ischemic stroke/TIA. Stepwise regression analysis suggested that body weight of ≤50 kg and diabetes mellitus were predictive of major bleeding in patients with prior ischemic stroke/TIA. Conclusions: Safety and effectiveness event rates were higher in patients with prior ischemic stroke/TIA than those without. This might be explained by differences in several risk profiles including age, body weight, renal function, and risk scores such as CHADS2 between the groups. Clinicaltrials.gov: NCT01582737.

Abstract WP524: Outcomes With Rivaroxaban in Patients With Nonvalvular Atrial Fibrillation and Worsening Renal Function

Introduction: Direct oral anticoagulants are widely used in patients with nonvalvular atrial fibrillation (AF) to reduce the risk of stroke and systemic embolism, however, there is not enough real-world data of their effectiveness and safety in patients with worsening renal function (WRF). Xarelto post-authorization safety and effectiveness study in Japanese patients with atrial fibrillation (XAPASS) is a prospective observational post-marketing surveillance study mandated by the Japanese authority. It aims to examine safety and effectiveness of rivaroxaban in everyday clinical practice. This analysis investigated one year outcomes among patients with WRF and stable renal function (SRF) in XAPASS.

Methods: One year follow-up data of 9578 patients enrolled in XAPASS were analyzed to evaluate baseline characteristics and safety/effectiveness profile among patients with WRF and SRF. WRF was defined as a decrease of more than 20% from enrollment creatinine clearance measurement at any time point during the study. SRF was defined as the absence of WRF at any time.

Results: We identified 1229 patients (12.8%) with WRF and 6280 patients (65.6%) with SRF among 9578 patients. WRF patients were significantly older, and had significantly higher mean CHA 2 DS 2 -VASc score and modified HAS-BLED score compared to SRF patients. Prevalence of hypertension, congestive heart failure, ischemic stroke/transient ischemic attack, and myocardial infarction was higher in WRF patients. There was no difference in rates of major bleeding (hazard ratio (HR) 1.20; 95% confidence interval (CI) 0.75-1.90; p=0.45) or the composite endpoint of stroke, systemic embolism or myocardial infarction (HR 1.06; 95% CI 0.65-1.71; p=0.82) between patients with WRF and SRF. WRF patients experienced a higher incidence of transfusion of 2 units or more (0.46 versus 0.14 events per 100 patient-years; HR 3.19; 95% CI 1.04-9.74; p=0.03) versus SRF patients. Rates of other major bleeding subgroups defined according to ISTH criteria were similar between patients with WRF and SRF.

Conclusions: WRF during rivaroxaban treatment did not significantly increase the rates of major bleeding or thromboembolic events, although it was associated with a higher incidence of transfusion of 2 units or more.

Abstract WP528: Safety and Effectiveness of Rivaroxaban Among Japanese Elderly Patients With Nonvalvular Atrial Fibrillation in Everyday Clinical Practice

Introduction: Nonvalvular atrial fibrillation (AF) is common in elderly patients, who face increased risk of thromboembolism and bleeding during antithrombotic therapy. Xarelto post-authorization safety & effectiveness study in Japanese patients with atrial fibrillation (XAPASS) is a prospective observational post-marketing surveillance study mandated by the Japanese authority. It aims to examine safety and effectiveness of rivaroxaban in everyday clinical practice. This analysis evaluated one-year outcomes and patient characteristics associated with major bleeding or thromboembolic events among elderly patients enrolled in XAPASS.

Methods: A total of 11,308 patients with AF newly starting rivaroxaban were enrolled between April 2012 and June 2014. As of September 2017, one year follow-up data were collected from 9578 patients, and 4685 patients (48.9%) were aged ≥75 years.

Results: Patients aged ≥75 years had higher rates of major bleeding (2.22 versus 1.35 events per 100 patient-years; p=0.004), and the composite endpoint of stroke, systemic embolism or myocardial infarction (2.41 versus 1.21 events per 100 patient-years; p<0.0001) compared with those aged <75 years. Rates of intracranial hemorrhage were less than 1% in both patient groups aged ≥75 years and <75 years (0.85 versus 0.59 events per 100 patient-years). There was no significant difference in major bleeding or thromboembolism among patients in age groups of 75-79, 80-84, and ≥85 years. Multivariate analysis identified hepatic impairment and concomitant use of acetylsalicylic acid as risk factors of major bleeding events in patients aged ≥75 years (p=0.041 and p<0.0001, respectively). History of stroke was identified as a risk factor of thromboembolic events in the same patient group (p<0.0001).

Conclusions: Although elderly patients had higher rates of bleeding and thromboembolic events than younger patients, no significant difference was found in the outcomes between age groups of 75-79, 80-84, and ≥85 years. Benefit and risk of antithrombotic therapy should be thoroughly assessed in elderly patients. Additionally, elderly patients with risk factors of bleeding or thromboembolic events should be carefully monitored while taking anticoagulants.

Patient-reported treatment satisfaction with rivaroxaban in Japanese non-valvular atrial fibrillation patients: an observational study

OBJECTIVES

Rivaroxaban has previously been shown to be as efficacious and safe as warfarin for the prevention of stroke in non-valvular atrial fibrillation (NVAF). Therefore, treatment satisfaction becomes an important consideration. Here we examine treatment satisfaction in Japanese NVAF patients who were switched from warfarin to rivaroxaban.

METHODS

Patient-reported outcome (PRO) data were collected as part of a prospective, multi-center, post-marketing surveillance (PMS) of a direct oral-anticoagulant, rivaroxaban, in Japan. The Anti-Clot Treatment Scale (ACTS) and the Treatment Satisfaction Questionnaire for Medication version II (TSQM-II) were collected at baseline, month 3, and month 6. Change in scores from baseline to month 3 and month 6 were assessed. Exploratory analyses included change in scores by patient characteristics. Safety and effectiveness of rivaroxaban were also assessed.

RESULTS

ACTS Burdens scores significantly improved at month 3 (54.6 ± 6.3) and month 6 (54.5 ± 6.5) compared to baseline (51.0 ± 7.6) (p < .001). ACTS Benefits score remained stable over time (baseline = 10.1 ± 2.8, month 3 = 10.2 ± 3.1, month 6 = 10.1 ± 3.1). Mean TSQM-II sub-scale scores significantly improved at month 3 and month 6 compared to baseline for all four domains (all p < .001).

CONCLUSIONS

Findings suggest treatment satisfaction may improve in Japanese NVAF patients after a switch from warfarin to rivaroxaban. Higher treatment satisfaction may translate into improved treatment adherence, which is critical for the long-term prevention of stroke.

Design and baseline characteristics of the Xarelto Post-Authorization Safety & Effectiveness Study in Japanese Patients with Atrial Fibrillation (XAPASS)

Background

The phase III Japanese Rivaroxaban Once‐Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (J‐ROCKET AF) showed that the rivaroxaban group had a lower event rate of intracranial bleeding than the warfarin group and that rivaroxaban was noninferior to warfarin for the principal safety outcome. However, safety and effectiveness data from unselected patients with AF in everyday clinical practice in Japan are lacking.

Methods

The Xarelto Post‐Authorization Safety & Effectiveness Study in Japanese Patients with Atrial Fibrillation (XAPASS) is a real‐world, prospective, single‐arm, observational study mandated by the Japanese authority as postmarketing surveillance. XAPASS involves patients with nonvalvular AF prescribed rivaroxaban. The principal safety outcome is a composite of major and nonmajor bleeding events, and the primary effectiveness outcome is the incidence of ischemic stroke, hemorrhagic stroke, noncentral nervous system systemic embolism, and myocardial infarction.

Results

In total, 11 308 patients were enrolled from April 2012 to June 2014. Their age was 73.1 ± 9.9 years, and their CHADS₂ score was 2.2 ± 1.3. Female patients, patients aged ≥75 years, patients with a body weight of ≤50 kg, and patients with a creatinine clearance of <50 mL/min constituted 38.1%, 48.7%, 19.5%, and 23.9% of all patients, respectively. Almost half (53.2%) of patients were prescribed other anticoagulants before starting rivaroxaban.

Conclusions

Data from this study will supplement those from the J‐ROCKET AF and provide practical information for the optimal use of rivaroxaban for stroke prevention in Japanese patients with AF (Clinicaltrials.gov: NCT01582737).

Safety and effectiveness of sorafenib in Japanese patients with hepatocellular carcinoma in daily medical practice: interim analysis of a prospective postmarketing all-patient surveillance study

BACKGROUND

Sorafenib was approved for treatment of unresectable hepatocellular carcinoma (HCC) in Japan in 2009. A prospective postmarketing all-patient surveillance (PMS) study was requested by Japanese authorities to confirm safety and effectiveness of sorafenib in Japanese HCC population.

METHODS

Patients with unresectable HCC treated with sorafenib were followed up for 12 months. Data on patient demographic characteristics, treatment status, clinical outcome, and adverse events (AEs) were collected.

RESULTS

This interim analysis included 1109 and 1065 patients evaluable for safety and effectiveness, respectively. Most patients (83.4 %) received the recommended initial dose of 400 mg twice daily. After a follow-up of 12-months, 89.8 % had discontinued treatment, most because of AEs (44.5 %) or progression (33.8 %). The most common drug-related adverse events (DRAE) were hand-foot skin reaction (51.4 %), liver dysfunction (26.4 %), diarrhea (25.1 %), and hypertension (21.6 %). The median overall survival (OS) was 348 days [95 % confidence interval (CI) 299-389 days], and the median duration of treatment was 87 days (95 % CI 78-98 days). Multivariate analyses identified baseline prognostic factors for longer OS, including female sex, low Child-Pugh score, Eastern Cooperative Oncology Group performance status 0, tumor stage I/II/III, low aspartate aminotransferase level, high hemoglobin level, hepatitis C and history of surgical resection.

CONCLUSIONS

In general, the safety and effectiveness findings in this PMS were consistent with findings from previous clinical studies. Sorafenib was well tolerated and clinically useful for Japanese patients.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01411436.

A large-scale prospective registration study of the safety and efficacy of sorafenib tosylate in unresectable or metastatic renal cell carcinoma in Japan: results of over 3200 consecutive cases in post-marketing all-patient surveillance

Objective

Real-life safety and efficacy of sorafenib in advanced renal cell carcinoma in a nationwide patient population were evaluated by post-marketing all-patient surveillance.

Methods

All patients with unresectable or metastatic renal cell carcinoma in Japan who started sorafenib therapy from February 2008 to September 2009 were registered and followed for up to 12 months. Baseline characteristics, treatment status, tumor response, survival and safety data were recorded by the prescribing physicians.

Results

Safety and efficacy were evaluated in 3255 and 3171 patients, respectively. The initial daily dose was 800 mg in 78.2% of patients. Median duration of treatment was 6.7 months and the mean relative dose intensity was 68.4%. Overall, 2227 patients (68.4%) discontinued the treatment by 12 months, half of which (52.0% of discontinued patients) were due to adverse events. The most common adverse drug reactions were hand–foot skin reaction (59%), hypertension (36%), rash (25%) and increase in lipase/amylase (23%). The median progression-free survival was 7.3 months (95% confidence intervals: 6.7–8.1), and the overall survival rate at 1 year was 75.4% (73.5–77.1). Prognostic factors for overall survival were mostly consistent with those in previous clinical trials in the univariate analysis and largely similar to those for progression-free survival and duration of treatment in the multivariate analysis.

Conclusions

Sorafenib for the treatment of advanced renal cell carcinoma under the labeled dose was feasible in daily medical practice, for its acceptable toxicity profile and favorable clinical benefit that were consistent with those in clinical trials.

The interaction between Lyn and FcεRIβ is indispensable for FcεRI-mediated human mast cell activation

BACKGROUND

FcεRIβ reportedly functions as an amplifier of the FcεRIγ-mediated activation signal using a reconstitution system. However, the amplification mechanisms in human mast cells (MCs) are poorly understood. We previously reported the hyperexpression of FcεRIβ of MCs in giant papillae from vernal keratoconjunctivitis patients, compared with that in conjunctivae from nonallergic conjunctivitis patients. Elucidation of the molecular mechanisms of the amplification induced by FcεRIβ should provide new targets for novel therapeutic interventions. The aim is to understand in greater details the function of FcεRIβ in human MC FcεRI expression and signaling.

METHODS

FcεRIβ and Lyn expression was reduced using a lentiviral shRNA silencing technique. Localization of Lyn and FcεRIβ in cultured MCs was examined by confocal microscopic analysis. Mediators were measured by ELISAs.

RESULTS

The diminution of FcεRIβ significantly downregulated cell surface FcεRI expression and FcεRI-mediated mediator release/production. The downregulation of FcεRI-mediated degranulation was not only due to the decrease in FcεRI expression. The diminution of FcεRIβ inhibited the redistribution of Lyn within the cell membrane following IgE sensitization. The diminution of Lyn in MCs significantly downregulated FcεRI-mediated degranulation. The recombinant cell-penetrating forms of phosphorylated FcεRIβ immunoreceptor tyrosine-based activation motif (ITAM) for intracellular delivery disturbed the interaction between Lyn and phosphorylated endogenous FcεRIβ ITAM, resulted in inhibiting IgE-dependent histamine release from MCs in vitro and from giant papillae specimens ex vivo.

CONCLUSION

The interaction between Lyn and FcεRIβ is indispensable for FcεRI-mediated human MC activation, and specific inhibition of the interaction may represent a new therapeutic strategy for the treatment of human allergic diseases.

FcepsilonRI-mediated thymic stromal lymphopoietin production by interleukin-4-primed human mast cells

A significant increase of mRNA expression of thymic stromal lymphopoietin (TSLP) has been reported in the bronchial mast cells (MCs) of asthmatic subjects; however, the mechanism underlying the upregulation of TSLP mRNA and protein remains unknown. FcepsilonRI-mediated activation of human MCs upregulated TSLP mRNA expression by 5.2+/-2.9-fold, while activation of the MCs using lipopolysaccharide and polyriboinosinic:polyribocytidylic acid failed to upregulate TSLP. Stimulation of MCs with interleukin (IL)-4 alone did not affect the TSLP mRNA expression, while pre-incubation of MCs with IL-4 for 48 h significantly enhanced the FcepsilonRI-mediated TSLP mRNA expression (by 53.7+/-15.9-fold; p<0.05) and the amount of TSLP in the cell pellets increased significantly from 23.4+/-4.3 pg mL(-1) to 121.5+/-3.7 pg mL(-1) (p<0.0001). However, the released TSLP was rapidly degraded by proteases that were released by MCs. We identified the population of cells expressing TSLP in the lungs of 16 asthmatic and 11 control subjects by immunohistochemistry. The percentage of TSLP-positive MCs in the total population of MCs was significantly increased in asthmatic airways (p<0.0001). Thus, MCs are able to store TSLP intracellularly and to produce TSLP following aggregation of FcepsilonRI in the presence of IL-4.

The airway smooth muscle CCR3/CCL11 axis is inhibited by mast cells

BACKGROUND

Airway smooth muscle hyperplasia is a feature of asthma, and increases with disease severity. CCR3-mediated recruitment of airway smooth muscle progenitors towards the airway smooth muscle bundle has been proposed as one possible mechanism involved in airway smooth muscle hyperplasia. Mast cells are microlocalized to the airway smooth muscle bundle and whether mast cells influence CCR3-mediated migration is uncertain.

METHODS

We examined the expression of CCR3 by primary cultures of airway smooth muscle cells from asthmatics and nonasthmatics. CCR3 function was examined using intracellular calcium measurements, chemotaxis, wound healing, cell proliferation and survival assays. We investigated the recovery and function of both recombinant and airway smooth muscle-derived CCL11 (eotaxin) after co-culture with beta-tryptase and human lung mast cells.

RESULTS

Airway smooth muscle expressed CCR3. Airway smooth muscle CCR3 activation by CCL11 mediated intracellular calcium elevation, concentration-dependent migration and wound healing, but had no effect on proliferation or survival. Co-culture with beta-tryptase or mast cells degraded recombinant and airway smooth muscle-derived CCL11, and beta-tryptase inhibited CCL11-mediated airway smooth muscle migration.

CONCLUSIONS

CCL11 mediates airway smooth muscle migration. However co-culture with beta-tryptase or mast cells degraded recombinant and airway smooth muscle-derived CCL11 and inhibited CCL11-mediated airway smooth muscle migration. Therefore these findings cast doubt on the importance of the CCL11/CCR3 axis in the development of airway smooth muscle hyperplasia in asthma.

Impacts of excision repair cross-complementing gene 1 (ERCC1), dihydropyrimidine dehydrogenase, and epidermal growth factor receptor on the outcomes of patients with advanced gastric cancer

Using laser-captured microdissection and a real-time RT-PCR assay, we quantitatively evaluated mRNA levels of the following biomarkers in paraffin-embedded gastric cancer (GC) specimens obtained by surgical resection or biopsy: excision repair cross-complementing gene 1 (ERCC1), dihydropyrimidine dehydrogenase (DPD), methylenetetrahydrofolate reductase (MTHFR), epidermal growth factor receptor (EGFR), and five other biomarkers related to anticancer drug sensitivity. The study group comprised 140 patients who received first-line chemotherapy for advanced GC. All cancer specimens were obtained before chemotherapy. In patients who received first-line S-1 monotherapy (69 patients), low MTHFR expression correlated with a higher response rate (low: 44.9% vs high: 6.3%; P=0.006). In patients given first-line cisplatin-based regimens (combined with S-1 or irinotecan) (43 patients), low ERCC1 correlated with a higher response rate (low: 55.6% vs high: 18.8%; P=0.008). Multivariate survival analysis of all patients demonstrated that high ERCC1 (hazard ratio (HR): 2.38 (95% CI: 1.55-3.67)), high DPD (HR: 2.04 (1.37-3.02)), low EGFR (HR: 0.34 (0.20-0.56)), and an elevated serum alkaline phosphatase level (HR: 1.00 (1.001-1.002)) were significant predictors of poor survival. Our results suggest that these biomarkers are useful predictors of clinical outcomes in patients with advanced GC.

Clinical significance of dihydropyrimidine dehydrogenase (DPD), epidermal growth factor receptor (EGFR), and excision repair cross-complementing gene 1 (ERCC1) gene expression of tumor tissue in patients with advanced gastric cancer

4629

Background: Many methods for predicting the susceptibility of a gastric cancer(GC) to chemotherapy have been investigated. However, the clinical significance of biomarkers in GC cells remains unclear. There is a need for exploratory evaluations to understand the clinical implications of biomarkers. Methods: This study consisted of 151 patients (pts) who received chemotherapy for advanced GC. cDNA was derived from the laser-captured tumor cells of cancer specimens obtained by surgical resection or endoscopic biopsy and analyzed to determine mRNA expression relative to an internal reference gene (β-actin) using real-time RT-PCR method. Gene expression levels of thymidylate synthase (TS), DPD, orotate phosphoribosyl transferase, dihydrofolate reductase (DHFR), ERCC-1, EGFR and 22 other biomarkers related to anticancer drug sensitivity were measured. Results: DPD, EGFR, and ERCC1 gene expressions were significantly correlated with survival ( Table ). Multivariate analysis revealed that high DPD (p=0.0002, RR=2.67 [95% CI, 1.62–4.25]), low EGFR (p=0.0005, RR=0.29 [0.18–0.50]), and high ERCC1 (p<0.0001, RR=2.27 [1.45–3.47]) gene expressions were independently related to poor survival. As for first-line chemotherapy, an analysis of 60 pts treated with S-1 showed that low DHFR gene expression significantly correlated with a longer time to progression (TTP) (p=0.0017). An analysis of 54 pts who received cisplatin containing regimens ( + irinotecan or + S-1) as first-line therapy showed that low ERCC1 gene expression was slightly related to a better response (p=0.053). Conclusions: These results indicate that expression of DPD, ERCC1, and EGFR gene expressions in cancer specimens have predictive value for the outcome of advanced GC pts treated with chemotherapy. Low DHFR gene expression could be a predictor of a long TTP in patients receiving S-1 therapy.

[Table: see text]

No significant financial relationships to disclose.

Roles of the transmembrane domain and the cytoplasmic domain of Fc?RI? in immunoglobulin E-mediated up-regulation of surface Fc?RI expression

BACKGROUND

Human mast cells express both Fc epsilon RI alpha and Fc gamma RI alpha. IgE up-regulates Fc epsilon RI alpha expression, but IgG1 does not up-regulate Fc gamma RI alpha expression. The transmembrane domain (TM) of Fc gamma RI alpha determines the stability of cell surface expression of this receptor.

OBJECTIVE

The aim of this study was to clarify the roles of the TM and cytoplasmic domain (CY) of Fc epsilon RI alpha in IgE-mediated Fc epsilon RI up-regulation.

METHODS

Chimeric receptors created by domain shuffling between Fc epsilon RI alpha and Fc gamma RI alpha were transduced into human mast cell line HMC-1. Cell surface expression of the chimeric receptors and the effect of IgE or IgG1 on chimeric receptor expression were examined by FACS. The association of the chimeric receptors with FcR gamma was investigated by immunoprecipitation.

RESULTS

The results showed that the TM and CY of Fc epsilon RI alpha are not essential for IgE-mediated up-regulation of surface Fc epsilon RI.

CONCLUSION

The extracellular domain of each Fc receptor determines the diversity of Ig-regulated Fc receptor expression.

Impact of dihydrofolate reductase (DHFR) and thymidylate synthase (TS) on outcomes of postoperative patients with gastric cancer

4053

Background: The clinical significance of biomarkers in resected gastric cancer (GC) remains unclear. Detailed exploratory evaluations are required to better understand the clinical implications of biomarkers. Methods: The study group comprised 87 patients who received chemotherapy for recurrent or residual GC after resection of their primary tumors at National Cancer Center Hospital. The patients received 1 to 5 regimens of chemotherapy (median: 2). Total RNA was isolated from laser-captured tumor cells of the resected cancer specimens, and the gene expressions of TS, DPD, DHFR, ERCC1, MRP1, and 22 other biomarkers related to anticancer drug sensitivity were quantitatively evaluated by a real-time RT-PCR assay. Results: The gene expressions of TS, DHFR, MTHFD, RRM1, and ERCC1 were significantly related to survival ( Table ). Multivariate analysis revealed that high DHFR (p < 0.001, RR = 1.70 [95% CI, 1.28–2.29]) and high TS (p = 0.004, RR = 1.53 [1.15–2.06]) gene expressions were independently related to poor survival. As compared with intestinal type tumors, diffuse type tumors had higher DPD (p < 0.001) and lower Her2 (p < 0.001) gene expressions. As for first line chemotherapy, an analysis of 29 patients treated with S-1, an oral DPD inhibitory fluoropyrimidine, showed that patients with diffuse type tumors tended to respond better (p = 0.13) than those with intestinal type tumors. An analysis of 29 patients treated with cisplatin plus irinotecan as first line therapy showed that low ERCC1 gene expression was slightly but not significantly related to a better response (p = 0.087). Analyses of patients treated with other first line regimens revealed no significant correlation of any biomarker with response. Conclusions: Increased gene expressions of DHFR and TS in surgical specimens are significantly predictors of poor outcomes in postoperative patients with GC.

[Table: see text]

[Table: see text]

Secretion of interleukin-1 receptor antagonist from human mast cells after immunoglobulin E-mediated activation and after segmental antigen challenge

Mast cells produce substances with antiinflammatory properties in addition to their capacity to release proinflammatory mediators. To further probe the antiinflammatory aspect of mast-cell function we investigated the ability of human mast cells (huMCs) to produce interleukin (IL)-1 receptor antagonist (IL-1ra) in response to high-affinity Fc receptor for immunoglobulin E (Fcalpha RI) aggregation, and examined IL-1ra in bronchoalveolar lavage fluid (BALF) to determine whether it might be of mast-cell origin. Using a ribonuclease protection assay, flow cytometry, and enzyme-linked immunosorbent assay (ELISA), IL-1ra message and protein were found to be constitutively expressed in cultured huMCs. Upon stimulation through Fcalpha RI, IL-1ra message was upregulated in huMCs and IL-1ra protein secreted from cultured huMCs and isolated human lung mast cells. By immunoblot analysis, huMCs were found to produce the 17-kD form of IL-1ra and the presence of IL-1ra in human lung mast cells was confirmed by immunohistochemistry. In BALF obtained from allergic asthmatic subjects, IL-1ra production increased after specific antigen challenge, with the 17-kD isoform of IL-1ra predominating. These findings demonstrate that huMCs produce and release IL-1ra after Fcalpha RI aggregation, which may contribute to a local inhibition of IL-1-dependent effects on inflammation in the lung.

IgG-dependent activation of human mast cells following up-regulation of FcgammaRI by IFN-gamma

It has been reported that FcgammaRI is up-regulated on human mast cells (huMC) by IFN-gamma and aggregation of this receptor using mouse F(ab')(2) specific for receptor-bound, mouse anti-CD64 F(ab')(2) results in activation. To determine whether huMC can similarly be stimulated by aggregation of FcgammaRI-bound human IgG, IFN-gamma-treated, CD34(+)-derived, cultured huMC were sensitized with human immunoglobulins and activation was evaluated following addition of antibodies specific for each IgG isotype. Degranulation was also examined following simultaneous IgG- and IgE-dependent aggregation of FcgammaRI and Fc(epsilon)RI. Activation of IFN-gamma-treated huMC sensitized with 100 ng/ml IgG(1) resulted in 40% beta-hexosaminidase (beta-hex) release; minimal degranulation was observed using IgG(2), IgG(3) or IgG(4). IgG(1)-dependent activation led to PGD(2) and LTC(4) generation as well as elevated cytokine production, most notably TNF-alpha. Preincubation of cells with F(ab')(2) from CD64-specific clones 10.1 and 32.2 reduced IgG(1)-mediated beta-hex release by 46% and 74%, respectively. While IgG-dependent cell stimulation induced half-maximal degranulation by 11 min, IgE-dependent activation resulted in half maximal responses within 1 min. Simultaneous activation of huMC via FcgammaRI and Fc(epsilon)RI led to additive degranulation using suboptimal concentrations of IgG(1) and IgE. Activation of huMC thus may occur via monomeric IgG and FcgammaRI thereby providing a novel paradigm for huMC recruitment into inflammation.

A solid cystic tumor of the pancreas with ossification and possible malignancy, coexisting nonfusion of the pancreatic ducts

We report the case of a 34-year-old woman with a solid cystic tumor (SCT) of the pancreas accompanied by ossification and possible malignancy, coexisting nonfusion of the pancreatic ducts. There was a 24 x 29 x 33-mm mass with a prominent calcified lesion in the tail of the pancreas detected by abdominal ultrasonography, computed tomography, and magnetic resonance imaging. There were no distal metastases detected. Endoscopic retrograde pancreatography revealed nonfusion of the pancreatic ducts. The resected tumor consisted of solid and cystic components. The tumor was not encapsulated and included a severely ossified lesion inside. On microscopy, the tumor cells were small, eosinophilic, and proliferated in a solid or pseudo-papillary pattern. The tumor cells infiltrated into the surrounding normal pancreas parenchyma and invaded part of the mesentery. The immunostaining was positive for alpha-1-antitrypsin, neuron-specific enolase, vimentin, and chromogranin A. In the literature, only a few cases of SCT of the pancreas described ossification. As far as we know, only three cases of SCT of the pancreas, which demonstrated nonfusion of the pancreatic ducts, have been reported. Thus, SCT of the pancreas with ossification, possible malignancy, and coexisting nonfusion of the pancreatic ducts is extremely rare.

A comparison of mediators released or generated by IFN-gamma-treated human mast cells following aggregation of Fc gamma RI or Fc epsilon RI

The high affinity receptor for IgG (Fc gamma RI, CD64) is expressed on human mast cells, where it is up-regulated by IFN-gamma and, thus, may allow mast cells to be recruited through IgG-dependent mechanisms in IFN-gamma-rich tissue inflammation. However, the mediators produced by human mast cells after aggregation of Fc gamma RI are incompletely described, and it is unknown whether these mediators are distinct from those produced after activation of human mast cells via Fc epsilon RI. Thus, we investigated the release of histamine and arachidonic acid metabolites and examined the chemokine and cytokine mRNA profiles of IFN-gamma-treated cultured human mast cells after Fc gamma RI or Fc epsilon RI aggregation. Aggregation of Fc gamma RI resulted in histamine release and PGD(2) and LTC(4) generation. These responses were qualitatively indistinguishable from responses stimulated via Fc epsilon RI. Aggregation of Fc epsilon RI or Fc gamma RI led to an induction or accumulation of 22 cytokine and chemokine mRNAs. Among them, seven cytokines (TNF-alpha, IL-1beta, IL-5, IL-6, IL-13, IL-1R antagonist, and GM-CSF) were significantly up-regulated via aggregation of Fc gamma RI compared with Fc epsilon RI. TNF-alpha mRNA data were confirmed by quantitative RT-PCR and ELISA. Furthermore, we confirmed histamine and TNF-alpha data using IFN-gamma-treated purified human lung mast cells. Thus, aggregation of Fc gamma RI on mast cells led to up-regulation and/or release of three important classes of mediators: biogenic amines, lipid mediators, and cytokines. Some cytokines, such as TNF-alpha, were released and generated to a greater degree after Fc gamma RI aggregation, suggesting that selected biologic responses of mast cells may be preferentially generated through Fc gamma RI in an IFN-gamma-rich environment.

Further characterization of FcgammaRII and FcgammaRIII expression by cultured human mast cells

BACKGROUND

We have reported that resting human mast cells exhibit minimal expression for FcgammaRI, and that interferon-gamma will upregulate this expression. The expression of FcgammaRII and FcgammaRIII by human mast cells remains to be fully examined.

METHODS

To investigate FcgammaRII and FcgammaRIII expression, we determined mRNA and protein expression of FcgammaRII and FcgammaRIII in human peripheral blood CD34+ derived cultured mast cells by RT-PCR and flow cytometry. The expression of FcgammaRII and FcgammaRIII in intact and permeabilized mast cells was also compared. We measured histamine release to monitor mast cell degranulation following cross-linking of FcgammaRII.

RESULTS

We found by RT-PCR that resting human mast cells exhibit mRNA for FcgammaRIIA, FcgammaRIIb1, FcgammaRIIb2 and FcgammaRIII but not FcgammaRIIC. FACS analysis of Fcgamma receptors in intact versus permeabilized mast cells showed expression of FcgammaRII to be 42.2 +/- 3.9% and this was unchanged by permeabilization. FcgammaRIII protein expression was minimal and this was also unchanged by permeabilization. Aggregation of FcgammaRII on human mast cells led to no significant degranulation as evidenced by histamine release.

CONCLUSIONS

In addition to FcgammaRI expression, human mast cells express FcgammaRIIA, FcgammaRIIb1, FcgammaRIIb2 and FcgammaRIII mRNA, and significant surface expression of FcgammaRII. Aggregation of FcgammaRII on cultured human mast cells in this model was not followed by histamine release.