Altered cochlear fibrocytes in a mouse model of DFN3 nonsyndromic deafness

DFN3, an X chromosome-linked nonsyndromic mixed deafness, is caused by mutations in the BRN-4 gene, which encodes a POU transcription factor. Brn-4-deficient mice were created and found to exhibit profound deafness. No gross morphological changes were observed in the conductive ossicles or cochlea, although there was a dramatic reduction in endocochlear potential. Electron microscopy revealed severe ultrastructural alterations in cochlear spiral ligament fibrocytes. The findings suggest that these fibrocytes, which are mesenchymal in origin and for which a role in potassium ion homeostasis has been postulated, may play a critical role in auditory function.

A germ-line Tsc1 mutation causes tumor development and embryonic lethality that are similar, but not identical to, those caused by Tsc2 mutation in mice

Tuberous sclerosis (TS) is characterized by the development of hamartomas in various organs and is caused by a germ-line mutation in either TSC1 or TSC2 tumor suppressor genes. From the symptomatic resemblance among TS patients, involvement of TSC1 and TSC2 products in a common pathway has been suggested. Here, to analyze the function of the Tsc1 product, we established a line of Tsc1 (TSC1 homologue) knockout mouse by gene targeting. Heterozygous Tsc1 mutant (Tsc1(+/-)) mice developed renal and extra-renal tumors such as hepatic hemangiomas. In these tumors, loss of wild-type Tsc1 allele was observed. Homozygous Tsc1 mutants died around embryonic days 10.5-11.5, frequently associated with neural tube unclosure. As a whole, phenotypes of Tsc1 knockout mice resembled those of Tsc2 knockout mice previously reported, suggesting that the presumptive common pathway for Tsc1 and Tsc2 products may also exist in mice. Notably, however, development of renal tumors in Tsc1(+/-) mice was apparently slower than that in Tsc2(+/-) mice. The Tsc1 knockout mouse described here will be a useful model to elucidate the function of Tsc1 and Tsc2 products as well as pathogenesis of TS.

Generation and characterization of mutant mice lacking ryanodine receptor type 3

The ryanodine receptor type 3 (RyR-3) functions as a Ca2+-induced Ca2+ release (CICR) channel and is distributed in a wide variety of cell types including skeletal muscle and smooth muscle cells, neurons, and certain non-excitable cells. However, the physiological roles of RyR-3 are totally unclear. To gain an insight into the function of RyR-3 in vivo, we have generated mice lacking RyR-3 by means of the gene targeting technique. The mutant mice thus obtained showed apparently normal growth and reproduction. Although Ca2+-induced Ca2+ release from intracellular Ca2+ stores of the mutant skeletal muscle differed in Ca2+ sensitivity from that of wild-type muscle, excitation-contraction coupling of the mutant muscle seemed to be normal. Moreover, we could not find any significant disturbance in the smooth muscle and lymphocytes from the mutant mice. On the other hand, the mutant mice showed increased locomotor activity, which was about 2-fold greater than that of the control mice. These results indicate that the loss of RyR-3 causes no gross abnormalities and suggest that the lack of RyR-3-mediated Ca2+ signaling results in abnormalities of certain neurons in the central nervous system.

Targeted disruption of the homeobox transcription factor Bapx1 results in lethal skeletal dysplasia with asplenia and gastroduodenal malformation

BACKGROUND

NK homeobox genes have been shown to play important roles in cell-type specification and organogenesis. Murine Bapx1, a member of NK homeobox gene family, is expressed in all the cartilageous tissues that undergo endochondral bone formation, and in gut mesentery during embryogenesis, suggesting that Bapx1 may be a key transcription factor ragulating the development of these organs.

RESULTS

We generated Bapx1-deficient mice by gene targeting. Bapx1-/- mice exhibited lethal skeletal dysplasia, with abnormal development of the vertebral column and some craniofacial bones, accompanied with asplenia and gastroduodenal malformation. We showed that the proliferative activity of the sclerotome cells, forming the vertebral column, was significantly reduced in Bapx1-/- embryos. The sclerotome cells of the mutants appeared to migrate and condense normally, but subsequent differentiation into the mature vertebral bodies and intervertebral discs were affected. The sclerotome cells in the vertebral bodies failed to differentiate into hypertrophic chondrocytes, as revealed by the undetected expression of Col10a1 and Osteopontin, and the sclerotome cells in the intervertebral discs failed to express the typical extracellular matrix proteins Col2a1, Col9a2 and aggrecan. Furthermore, we investigated the effect of loss of Bapx1 on the expression of some transcription factors, identified to be expressed in the developing sclerotome and be required for normal development of the vertebral column. Among them, we found that the expression of MFH-1 (mesenchyme forkhead-1), which was reported to regulate the proliferation and differentiation of sclerotome cells, was significantly reduced in ventromedial sclerotome cells in Bapx1-/- mice.

CONCLUSION

Our analysis provided evidence that Bapx1 was indispensable for normal development of ventromedial structure of vertebral column and some of craniofacial bones, splenogenesis and morphogenesis of gastroduodenal tract.

Effects of hemodialysis on cerebral circulation evaluated by transcranial Doppler ultrasonography

BACKGROUND AND PURPOSE

The effects of hemodialysis on the cerebral circulation of humans and the correlation between changes in blood flow velocity in the basal cerebral arteries and those of several physiological variables influenced by hemodialysis have been inadequately studied.

METHODS

Blood flow velocities were obtained from the middle cerebral artery and the basilar artery by transcranial Doppler ultrasonography in 27 patients receiving chronic maintenance hemodialysis immediately before and after the procedure. Changes in body weight, hematocrit, blood pressure, and arterial blood gases were recorded simultaneously.

RESULTS

There was a significant reduction in mean flow velocity in the middle cerebral artery (P < .01) and the basilar artery (P < .01) after hemodialysis. We observed a significant negative correlation between the relative change in mean flow velocity and the loss of weight after hemodialysis, the amount of fluid removed, and the increase in hematocrit in the middle cerebral artery and the basilar artery.

CONCLUSIONS

Hemodialysis and the associated physiological changes can significantly affect the cerebral circulation. Blood flow velocities in the middle cerebral artery and the basilar artery decrease significantly with hemodialysis. The loss of body weight, the amount of fluid removed, and the change in hematocrit significantly correlate with the change in mean flow velocity. The transcranial Doppler method can effectively monitor rapid changes in the cerebral circulation during potentially harmful procedures.

[Therapeutic effect of lisuride maleate on post-stroke depression]

Twenty post-stroke depressive patients who obtained more than 11 points on Self-Rating Questionnaire for Depression, were treated with 0.075 mg/day lisuride maleate for 12 weeks. The drug effect on depression was evaluated quantitatively by the Hamilton Rating Scale for Depression. The relationships between brain CT or MRI and SRQ-D score were investigated in 24 subjects. More than 80% of post-stroke depressive patients improved after lisuride maleate treatment for 8 or 12 weeks. In particular, depressed mood, hypobulia, sleep disturbance, anxiety, etc. were significantly improved compared to the baseline condition. As for the relationships with CT and/or MRI findings, the group with moderate to severe brain atrophy had a significantly higher grade of depressive state than those without.

Reversal of neurological deficits by levallorphan in patients with acute ischemic stroke

This study was conducted to examine the effect of the intramuscular injection of levallorphan tartrate (1.0 mg), a mixed agonist-antagonist opiate, on the neurological signs, symptoms, and vital signs in 19 patients with acute ischemic stroke. A temporary improvement of hemiplegia or hemiparesis was observed within several minutes after levallorphan injection in 13 of the patients. There were no significant alterations in blood pressure or pulse rate after injection. The findings indicate that levallorphan may have a temporary improving effect on neurological deficits in acute ischemic stroke. In addition, observation of the response to levallorphan may serve to predict the prognosis of the final neurological outcome in this type of patient.

Biomarker-based Bayesian randomized phase II clinical trial design to identify a sensitive patient subpopulation

The benefits and challenges of incorporating biomarkers into the development of anticancer agents have been increasingly discussed. In many cases, a sensitive subpopulation of patients is determined based on preclinical data and/or by retrospectively analyzing clinical trial data. Prospective exploration of sensitive subpopulations of patients may enable us to efficiently develop definitively effective treatments, resulting in accelerated drug development and a reduction in development costs. We consider the development of a new molecular-targeted treatment in cancer patients. Given preliminary but promising efficacy data observed in a phase I study, it may be worth designing a phase II clinical trial that aims to identify a sensitive subpopulation. In order to achieve this goal, we propose a Bayesian randomized phase II clinical trial design incorporating a biomarker that is measured on a graded scale. We compare two Bayesian methods, one based on subgroup analysis and the other on a regression model, to analyze a time-to-event endpoint such as progression-free survival (PFS) time. The two methods basically estimate Bayesian posterior probabilities of PFS hazard ratios in biomarker subgroups. Extensive simulation studies evaluate these methods' operating characteristics, including the correct identification probabilities of the desired subpopulation under a wide range of clinical scenarios. We also examine the impact of subgroup population proportions on the methods' operating characteristics. Although both methods' performance depends on the distribution of treatment effect and the population proportions across patient subgroups, the regression-based method shows more favorable operating characteristics.

Postmarketing Benefit-Risk Assessment for Erythropoiesis-Stimulating Agents Using a Health Care Database

BACKGROUND

While benefit-risk (B-R) assessment in the real-world setting is an important challenge for pharmacovigilance, few studies have explored this approach. To investigate the utility and limitations of B-R assessment using a health care database by applying the Benefit Risk Action Team (BRAT) framework, we have conducted a case study with erythropoietin agents.

METHODS

Postmarketing data from the Medical Data Vision health care database were used in a B-R comparison between methoxy polyethylene glycol-epoetin beta (continuous erythropoietin receptor activator; C.E.R.A.) and other erythropoiesis-stimulating agents (ESAs). Data were from patients with chronic kidney disease (CKD) treated with C.E.R.A. (n = 131: nondialysis, 109; hemodialysis, 22) or other ESAs (n = 542: nondialysis, 327; hemodialysis, 215) between July 2011 and March 2014.

RESULTS

The B-R profile for C.E.R.A. appeared to be similar to that for other ESAs in both nondialysis and hemodialysis patients with CKD, when benefits and risks were mainly assessed in terms of odds ratios. Despite various point estimates and confidence intervals for each outcome, the results of subgroup analyses showed no notable differences from the overall analysis in B-R assessment.

CONCLUSIONS

B-R assessment can be performed using the BRAT framework with a health care database, but limitations exist when using a single data source. Care should be taken when selecting data for extraction and defining outcomes of interest. Further research is necessary to facilitate practical application of this approach.

Use of mycophenolate mofetil in patients with pediatric and adult primary nephrotic syndrome: information from a Japanese hospital claims database

BACKGROUND

Current treatment for frequently relapsing, steroid-dependent, or steroid-resistant nephrotic syndrome focuses on immunosuppressive therapies. Although the clinical guideline suggests the use of mycophenolate mofetil (MMF), limited information is available on patients with primary nephrotic syndrome who receive off-label treatment with MMF in Japan.

METHOD

The dose, treatment duration, previous treatment, and characteristics of primary nephrotic syndrome patients receiving MMF were investigated using data from a Japanese hospital claims database (April 2008-September 2021).

RESULTS

Data on 424 primary nephrotic syndrome patients receiving MMF (146 patients < 18 years old; 278 patients ≥ 18 years old) were captured. The most common initial daily doses of MMF capsules (% of patients < 18 and ≥ 18 years old) were 1000 mg (31.9%, 36.8%), 1500 mg (16.0%, 23.8%), and 500 mg (23.6%, 17.3%), and the most common maximum daily doses were 1000 mg (43.8%, 32.9%), 1500 mg (23.6%, 28.9%), and 2000 mg (6.3%, 16.2%). Most patients (97.9%, 99.3%) were treated with a daily dose of 2000 mg or less. Among patients < 18 years old, the younger the patient, the lower the dose. MMF was used for more than 1 year in 30.8% of patients < 18 years old and in 28.8% of patients ≥ 18 years old.

CONCLUSIONS

Our study suggested that off-label use of MMF for primary nephrotic syndrome has increased since 2012 in Japan. The dose of MMF used in patients with primary nephrotic syndrome was generally within the approved dose range for lupus nephritis and transplant-related diseases in Japan.

Use of Mycophenolate Mofetil for Systemic Sclerosis and Systemic Sclerosis-Associated Interstitial Lung Disease: Information from a Japanese Hospital Claims Database

OBJECTIVES

Limited information is available on patients with systemic sclerosis (SSc) or SSc-associated interstitial lung disease (SSc-ILD) receiving mycophenolate mofetil (MMF) in Japan. The dose, treatment duration, and patient characteristics of SSc and SSc-ILD patients receiving MMF were investigated.

METHOD

We used data from a Japanese hospital claims database (2008-2020).

RESULTS

Data on 486 SSc patients ≥18 years old receiving MMF were captured; 314 had SSc complicated with ILD. The most common initial daily doses were 1000 mg (SSc, 39.5%; SSc-ILD, 38.1%) and 500 mg (SSc, 36.6%; SSc-ILD, 34.6%). The most common maximum daily doses were 1000 mg (SSc, 33.3%; SSc-ILD, 34.9%), 1500 mg (SSc, 24.4%; SSc-ILD, 23.1%), and 2000 mg (SSc, 23.8%; SSc-ILD, 24.4%). Doses ranged from 250 to 3000 mg/day and were similar for SSc and SSc-ILD patients. Over 27% of patients received treatment for >1 year. There was a gradual decrease in steroid doses during MMF treatment.

CONCLUSIONS

Our study suggests that the off-label use of MMF for SSc and SSc-ILD has been increasing annually since 2015 in Japan. The doses used in patients with SSc and SSc-ILD were similar to the approved doses of MMF for lupus nephritis in Japan.

Patient Preferences for Attributes of Chemotherapy for Lung Cancer: Discrete Choice Experiment Study in Japan

Our study objective was to determine lung cancer chemotherapy attributes that are important to patients in Japan. A discrete choice experiment survey in an anonymous web-based questionnaire format with a reward was completed by 200 lung cancer patients in Japan from November 25, 2019, to November 27, 2019. The relative importance of patient preferences for each attribute was estimated using a conditional logit model. A hierarchical Bayesian logit model was also used to estimate the impact of each demographic characteristic on the relative importance of each attribute. Of the 200 respondents, 191 with consistent responses were included in the analysis. In their preference, overall survival was the most important, followed by diarrhea, nausea, rash, bone marrow suppression (BMS), progression-free survival, fatigue, interstitial lung disease, frequency of administration, and duration of administration. The preferences were influenced by demographic characteristics (e.g., gender and age) and disease background (e.g., cancer type and stage). Interestingly, the experience of cancer drug therapies and adverse events had a substantial impact on the hypothetical drug preferences. For the Japanese lung cancer patients, improved survival was the most important attribute that influenced their preference for chemotherapy, followed by adverse events, including diarrhea, nausea, rash, and BMS. The preferences varied depending on the patient’s demographic and experience. As drug attributes can affect patient preferences, pharmaceutical companies should be aware of the patient preferences and develop drugs that respond to segmented market needs.

Impact of Tumor Assessment Frequency on Statistical Power in Randomized Cancer Clinical Trials Evaluating Progression-Free Survival

BACKGROUND

Progression-free survival (PFS) is frequently used as a primary endpoint in late-phase clinical trials for anti-metastatic cancer agents. Previous studies have indicated that the frequency of tumor assessment affects the statistical power for PFS because progression dates are inaccurate; however, this finding may be difficult to generalize because of its unrealistic assumptions. Therefore, we re-examined this issue under realistic assumptions and various scenarios that approximate actual clinical trials.

METHODS

Randomized clinical trials comparing two interventions against a solid tumor were simulated under conditions where progressive disease (PD)-dominant PFS or a non-negligible number of deaths (death-competitive PFS) contributed to PFS events, which are conditions that resemble clinical trials of first-line therapy and later-line therapy, respectively. We assessed the impact of tumor assessment frequency on the statistical power.

RESULTS

Under the PD-dominant PFS condition, even in extreme scenarios, statistical power loss was only approximately 3%. Under the death-competitive PFS condition, tumor assessment frequency affected the statistical power of PFS if the effect of the treatment on overall survival was lower than that on time to progression. In this case, loss of statistical power was often more than 10% in some realistic scenarios.

CONCLUSION

In trials investigating first-line treatments (PD-dominant PFS), tumor assessment frequency has a negligible impact on statistical power, whereas in trials investigating late-line therapies (death-competitive PFS), the potential impact of tumor assessment frequency on statistical power should be carefully evaluated at the design stage.

Change-point detection using diffusion maps for sleep apnea monitoring with contact-free sensors

Monitoring and improving the quality of sleep are crucial from a public health perspective. In this study, we propose a change-point detection method using diffusion maps for a more accurate detection of respiratory arrest points. Conventional change-point detection methods are limited when dealing with complex nonlinear data structures, and the proposed method overcomes these limitations. The proposed method embeds subsequence data in a low-dimensional space while considering the global and local structures of the data and uses the distance between the data as the score of the change point. Experiments using synthetic and real-world contact-free sensor data confirmed the superiority of the proposed method when dealing with noise, and it detected apnea events with greater accuracy than conventional methods. In addition to improving sleep monitoring, the proposed method can be applied in other fields, such as healthcare, manufacturing, and finance. This study will contribute to the development of advanced monitoring systems that adapt to diverse conditions while protecting privacy.

Abstract 409: Immunofluorescent digital slide technology to evaluate correlation between Glypican-3 expression and response to codrituzumab

Background: Codrituzumab/GC33/RO5137382 is a recombinant humanized monoclonal antibody against Glypican-3 (GPC3) which is highly expressed in HCC cells. As part of phase I clinical trial, GC-002US study, evaluating escalating doses of codrituzumab plus sorafenib in HCC, immunofluorescent staining of GPC3 were applied in addition to GPC3 immunohistochemistry (IHC) with conventional DAB staining. The objectives of this work were to compare GPC3 expression levels by different staining methods and evaluate the correlation between these GPC3 scores and codrituzumab activities.

Methods: Biopsies specimens (n = 34) collected at baseline in the phase I trial were evaluated by GPC3-IHC and immunofluorescent quantification digital slide (IQD) methods. GPC3-IHC were conducted using mouse anti-human GPC3 antibody, mouse GC33 (Ventana Medical Systems) as reported previously (Ikeda M. et al., Cancer Sci. 2014: 105; 455-462) and H scores were derived by two pathologists. For IQD, biopsy specimens were stained with same primary antibody, and were incubated with Qdot 655-conjugated secondary antibody. Fluorescent images of whole slides were obtained with the Nano-Zoomer (Hamamatsu Photonics K. K.). The IQD intensity score (immunofluorescent intensity per pixel) and cell score (immunofluorescent intensity per cell) were calculated respectively using MatLab (MathWorks Inc.).

Results: There was a statistically significant correlation between GPC3 H scores and IQD scores. Among GPC3 scores, only the IQD cell score was correlated with serum GPC3 C-terminus increase by treatment (p = 0.032), whereas in the patients treated with higher dose of GC33 (≥ 10 mg/kg/week) the cytoplasmic H and the IQD intensity score were also correlated with serum GPC3 C-terminus increase by treatment. Interestingly, increasing cut-off values of IQD cell score levels led to lower HR and longer PFS. Best HR with lowest p value was observed at a cut-off value of 66,183 (HR = 0.24, p = 0.038).

Conclusion: This study suggested that higher GPC3 expression on HCC cells quantified by IQD method was superior to other scores to predict codrituzumab activity, though this analysis was conducted only with limited number of subjects assessed. Further assessment and validation in clinical study of codrituzumab would be necessary to make a final conclusion on the clinical application of GPC3 IQD.

Citation Format: Takayoshi Tanaka, Yasuo Sugitani, Tokiya Abe, Miho Kawaida, Ken Yamazaki, Akinori Hashiguchi, Michiie Sakamoto, Toshihiko Ohtomo. Immunofluorescent digital slide technology to evaluate correlation between Glypican-3 expression and response to codrituzumab. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 409.