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result(s) for
"Blais, Jaime D"
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Tolvaptan in Later-Stage Autosomal Dominant Polycystic Kidney Disease
2017
In a trial involving patients with later-stage ADPKD, the V
2
-receptor antagonist tolvaptan resulted in a slower decline than placebo in the estimated GFR over a 1-year period, which may slow the onset of end-stage kidney disease.
Journal Article
Tolvaptan use in cancer patients with hyponatremia due to the syndrome of inappropriate antidiuretic hormone: a post hoc analysis of the SALT‐1 and SALT‐2 trials
by
Chiodo, Joseph
,
Zhou, Wen
,
Glaser, Linda A.
in
Administration, Oral
,
Aged
,
Antidiuretic Hormone Receptor Antagonists - administration & dosage
2017
Hyponatremia is a common electrolyte disorder in cancer patients and has been associated with poor prognosis. A frequent cause of cancer‐related hyponatremia is the syndrome of inappropriate antidiuretic hormone (SIADH). This study was a post hoc subgroup analysis of the SALT‐1 (Study of Ascending Levels of Tolvaptan in Hyponatremia) and SALT‐2 clinical trials. Hyponatremic subjects with SIADH and cancer received the oral selective vasopressin V2‐receptor antagonist tolvaptan (n = 12) or matching placebo (n = 16) once‐daily for 30 days. The initial tolvaptan dose (15 mg) was titrated over 4 days to 30 or 60 mg per day, as needed, according to serum sodium level and tolerability. Baseline serum sodium levels in the SIADH/cancer cohort of the SALT trials was 130 and 128 mEq/L for tolvaptan and placebo, respectively. Mean change from baseline in average daily serum sodium AUC for tolvaptan relative to placebo was 5.0 versus −0.3 mEq/L (P < 0.0001) at day 4, and 6.9 versus 1.0 mEq/L (P < 0.0001) at day 30; the observed treatment effects were similar to those in the overall SIADH population (i.e., with and without cancer) at both time points. Serum sodium normalization was observed in 6/12 and 0/13 subjects at day 4 and 7/8 and 2/6 subjects at day 30 in the tolvaptan and placebo groups, respectively (P < 0.05 for both). Common treatment‐emergent AEs for tolvaptan were consistent with previously reported results. In this post hoc study of the SALT trial population, oral tolvaptan was an effective and safe therapy for the treatment of hyponatremia in subjects with SIADH and cancer. Hyponatremia resulting from para‐neoplastic Syndrome of Inappropriate Antidiuretic Hormone is common in many types of cancer and correlates with poor outcomes. In this subanalysis of the Study of Ascending Levels of Tolvaptan in Hyponatremia (SALT) clinical trials, once‐daily oral tolvaptan safely restored serum sodium levels in cancer patients with SIADH, thereby reducing the need for fluid restriction and electrolyte infusions.
Journal Article
Clinical Pattern of Tolvaptan-Associated Liver Injury in Subjects with Autosomal Dominant Polycystic Kidney Disease: Analysis of Clinical Trials Database
by
Alpers, David H.
,
Kaplowitz, Neil
,
Smotzer, Dan M.
in
Clinical trials
,
Conflicts of interest
,
Cysts
2015
Introduction
Subjects with autosomal dominant polycystic kidney disease (ADPKD) who were taking tolvaptan experienced aminotransferase elevations more frequently than those on placebo in the TEMPO 3:4 (Tolvaptan Efficacy and Safety in Management of Autosomal Dominant Polycystic Kidney Disease and its Outcomes) clinical trial.
Methods
An independent, blinded, expert Hepatic Adjudication Committee re-examined data from TEMPO 3:4 and its open-label extension TEMPO 4:4, as well as from long-term (>14 months) non-ADPKD tolvaptan trials, using the 5-point Drug-Induced Liver Injury Network classification.
Results
In TEMPO 3:4, 1445 subjects were randomized 2:1 (tolvaptan vs. placebo) and 1441 had post-baseline assessments of hepatic injury. Sixteen patients on tolvaptan and one on placebo had significant aminotransferase elevations judged to be at least probably related to study drug. No association with dose or systemic exposure was found. Two of 957 subjects taking tolvaptan (0.2 %) and zero of 484 taking placebo met the definition of a Hy’s Law case. One additional Hy’s Law case was identified in a TEMPO 4:4 subject who had received placebo in the lead study. The onset of a hepatocellular injury occurred between 3 and 18 months after starting tolvaptan, with gradual resolution over the subsequent 1–4 months. None of the events were associated with liver failure or chronic liver injury/dysfunction. No imbalance in hepatic events was observed between tolvaptan and placebo in lower-dose clinical trials of patients with hyponatremia, heart failure, or cirrhosis.
Conclusions
Although hepatocellular injury following long-term tolvaptan treatment in ADPKD subjects was infrequent and reversible, the potential for serious irreversible injury exists. Regular monitoring of transaminase levels is warranted in this patient population.
Journal Article
Performance of an Artificial Multi-observer Deep Neural Network for Fully Automated Segmentation of Polycystic Kidneys
by
Harris, Peter C.
,
Torres, Vicente E.
,
King, Bernard F.
in
Artificial neural networks
,
Automation
,
Classification
2017
Deep learning techniques are being rapidly applied to medical imaging tasks—from organ and lesion segmentation to tissue and tumor classification. These techniques are becoming the leading algorithmic approaches to solve inherently difficult image processing tasks. Currently, the most critical requirement for successful implementation lies in the need for relatively large datasets that can be used for training the deep learning networks. Based on our initial studies of MR imaging examinations of the kidneys of patients affected by polycystic kidney disease (PKD), we have generated a unique database of imaging data and corresponding reference standard segmentations of polycystic kidneys. In the study of PKD, segmentation of the kidneys is needed in order to measure total kidney volume (TKV). Automated methods to segment the kidneys and measure TKV are needed to increase measurement throughput and alleviate the inherent variability of human-derived measurements. We hypothesize that deep learning techniques can be leveraged to perform fast, accurate, reproducible, and fully automated segmentation of polycystic kidneys. Here, we describe a fully automated approach for segmenting PKD kidneys within MR images that simulates a multi-observer approach in order to create an accurate and robust method for the task of segmentation and computation of TKV for PKD patients. A total of 2000 cases were used for training and validation, and 400 cases were used for testing. The multi-observer ensemble method had mean ± SD percent volume difference of 0.68 ± 2.2% compared with the reference standard segmentations. The complete framework performs fully automated segmentation at a level comparable with interobserver variability and could be considered as a replacement for the task of segmentation of PKD kidneys by a human.
Journal Article
Standardizing total kidney volume measurements for clinical trials of autosomal dominant polycystic kidney disease
by
Erickson, Bradley J
,
Edwards, Marie E
,
Torres, Vicente E
in
Clinical trials
,
Datasets
,
Diseases
2019
Abstract
Background
The ability of unstandardized methods to track kidney growth in clinical trials for autosomal dominant polycystic kidney disease (ADPKD) has not been critically evaluated.
Methods
The Tolvaptan Efficacy and Safety Management of ADPKD and its Outcomes (TEMPO) 3:4 study involved baseline and annual magnetic resonance follow-up imaging yearly for 3 years. Total kidney volume (TKV) measurements were performed on these four time points in addition to the baseline imaging in TEMPO 4:4, initially by Perceptive Informatics (Waltham, MA, USA) using planimetry (original dataset) and for this study by the Mayo Translational PKD Center using semiautomated and complementary automated methods (sequential dataset). In the original dataset, the same reader was assigned to all scans of individual patients in TEMPO 3:4, but readers were reassigned in TEMPO 4:4. Two placebo-treated cohorts were included. In the first (n = 158), intervals between the end of TEMPO 3:4 and the start of TEMPO 4:4 scan visits ranged from 12 to 403 days; in the second (n = 95), the same scan (measured twice) visit was used for both.
Results
Growth rates in TEMPO 3:4 were similar in the original and sequential datasets (5.5 and 5.9%/year). Growth rates during the TEMPO 3:4 to TEMPO 4:4 interval were higher in the original (13.7%/year) but were not different in the sequential dataset (4.0%/year). Comparing volumes from the same images, TKVs showed a bias of 2.2% [95% confidence interval (CI) −5.2-9.7] in the original and −0.16% (95% CI −1.91-1.58) in the sequential dataset.
Conclusions
Despite using the same software, TKV and growth rate changes were present, likely due to reader differences in the transition from TEMPO 3:4 to TEMPO 4:4 in the original but not in the sequential dataset. Robust, standardized methods are essential in ADPKD trials to minimize errors in serial TKV measurements.
Journal Article
ER stress-regulated translation increases tolerance to extreme hypoxia and promotes tumor growth
2005
Tumor cell adaptation to hypoxic stress is an important determinant of malignant progression. While much emphasis has been placed on the role of HIF‐1 in this context, the role of additional mechanisms has not been adequately explored. Here we demonstrate that cells cultured under hypoxic/anoxic conditions and transformed cells in hypoxic areas of tumors activate a translational control program known as the integrated stress response (ISR), which adapts cells to endoplasmic reticulum (ER) stress. Inactivation of ISR signaling by mutations in the ER kinase PERK and the translation initiation factor eIF2α or by a dominant‐negative PERK impairs cell survival under extreme hypoxia. Tumors derived from these mutant cell lines are smaller and exhibit higher levels of apoptosis in hypoxic areas compared to tumors with an intact ISR. Moreover, expression of the ISR targets ATF4 and CHOP was noted in hypoxic areas of human tumor biopsy samples. Collectively, these findings demonstrate that activation of the ISR is required for tumor cell adaptation to hypoxia, and suggest that this pathway is an attractive target for antitumor modalities.
Journal Article