Effect of Oral CNSA-001 (sepiapterin, PTC923) on gastric accommodation in women with diabetic gastroparesis: A randomized, placebo-controlled, Phase 2 trial

AIMS

Diabetic gastroparesis may be associated with impaired nitric oxide metabolism and reduced tetrahydrobiopterin (BH₄) synthesis. Oral treatment with CNSA-001 (sepiapterin, currently known as PTC923) increased BH₄ levels in humans in a previous study. This Phase 2 study evaluated CNSA-001 in women with diabetic gastroparesis.

METHODS

Non-pregnant diabetic women with moderate/severe symptomatic gastroparesis, delayed gastric emptying, and impaired gastric accommodation (nutrient satiety testing) were randomized to 10mg/kg BID CNSA-001 or matching placebo for 14days. The primary endpoint was change in gastric accommodation (maximal tolerated liquid meal volume) at 14- and 28-days' follow-up.

RESULTS

Gastric accommodation improved in CNSA-001-treated vs. placebo-treated subjects at 28days (least squares mean [LSM] difference: 98 [95% CI 36 to 161], p=0.0042). Subjects' ratings of bloating, fullness, nausea, and pain were lower vs. baseline in the CNSA-001 group at 14 and 28days, though these improvements were not observed consistently in placebo-treated subjects. There were no significant group differences in upper gastrointestinal symptom scores, and in gastric emptying breath test parameters. CNSA-001 was well tolerated, with no withdrawals for adverse events.

CONCLUSIONS

CNSA-001 improved gastric accommodation in women with diabetic gastroparesis. Further evaluation of CNSA-001 in gastroparesis is warranted; ClinicalTrials.gov number, NCT03712124.

Oropharyngeal pH monitoring for the detection of liquid and aerosolized supraesophageal gastric reflux

The association between gastroesophageal reflux disease (GERD) and extraesophageal symptoms is poorly understood and difficult to document. pH monitoring in this group of patients has resulted in conflicting data due to lack of diagnostic sensitivity. Recently, a new sensitive pH device for detection of liquid and aerosolized droplets in the oropharynx (The Dx-pH Measurement System [Dx-pH]) has become available. Our hypothesis is that we will be able to improve our ability to identify and understand this group of patients with this device. The aim of this preliminary observation study was to compare the results of this new device to the standard esophageal and pharyngeal pH probes in a small group of patients with extraesophageal symptoms. Patients with suspected extraesophageal GER symptoms underwent traditional 24-hour esophago-pharyngeal pH monitoring (24pH) simultaneous with Dx-pH monitoring in the oropharynx. Tracings were reviewed for comparison and correlation between the two probes, with an event in the Dx-pH Probe being defined as a rapid drop >3 standard deviation from baseline. Fifteen patients (10 females, 5 males) with mean age of 57.5 years (range, 25-75) were studied. The predominant chief complaint included 12/15 chronic cough, 2/15 asthma; and 1/15 throat clearing. All Dx-pH events were preceded and associated with distal esophageal pH drops in a progressive ante grade manner. Ten patients had 1-13 abnormal oropharyngeal pH events as measured by Dx-pH monitoring with a total of 48 events. The median pH of reflux events had a statistically significant increase from 3.1 at the distal esophageal probe to 5.2 at the pharynx and 5.6 at the oropharynx, the latter being 80% higher than the distal esophageal probe (P<0.001). The percentage of acid events decreased in a cephalad manner from 66.7% at distal esophagus to 25% at the pharynx and only 6.25% at the oropharyngeal Dx-pH Probe, with the remaining events being weakly acidic. Dx-pH Probe is a new sensitive oropharyngeal pH device whose values correlate well with the gold-standard 24-hour pH device, and appears to accurately detect pH events that begin at the distal esophagus and travel upward to the oropharynx. This device suggests that supraesophageal events manifest themselves as rapid pH drops (>10%), which are likely not to be identified using the standard criteria of pH <4 due to the gradient of increasing pH from the lower esophagus to the oropharynx.

Reduced tissue thyroid hormone levels in fatal illness

Patients with severe nonthyroidal illnesses (NTIs) frequently have decreased serum concentrations of triiodothyronine (T3) and less often of thyroxine (T4) without clear evidence of hypothyroidism. To determine whether T3 and T4 levels are also reduced in the tissues, we analyzed autopsy samples from 12 patients dying of NTI and 10 previously healthy individuals dying suddenly from trauma. Mean serum T3, T4, and free T4 index values were lower by 79%, 71%, and 49%, respectively, in the NTI group than in controls, but serum thyrotropin (TSH) values did not differ significantly. Mean T3 concentrations in cerebral cortex, hypothalamus, pituitary, liver, kidney, and lung were lower in the NTI group than in controls by 43% to 76%, but mean values in heart and skeletal muscle did not differ significantly between the groups. The mean liver T4 concentration was 66% lower in the NTI group, but mean T4 concentrations in the cerebral cortex were similar in the two groups. These results indicate that many tissues may be deficient in thyroid hormones in patients with fatal NTI, although the severity of the reduction in thyroid hormone concentrations may vary from one organ to another.

Chronic hoarseness secondary to gastroesophageal reflux disease: documentation with 24-h ambulatory pH monitoring

Gastroesophageal reflux (GER) has been implicated in otolaryngologic problems, particularly chronic hoarseness that cannot be attributed to other causes. To study this relationship, we used 24-h ambulatory intraesophageal or dual pharyngoesophageal pH monitoring in 33 patients with chronic hoarseness and laryngeal lesions suggestive of acid irritation. Twenty-six of the patients (78.8%) had pH evidence of severe GER, being at least three times greater than the upper limit of normal. In contrast to 19 patients with proven esophagitis, this GER was worse in the upright position. Of 15 patients with both pharyngeal and esophageal probes, three had esophagopharyngeal reflux, and two had atypical unexplained pharyngeal decreases in pH to below 4.0. Less than half of the 33 patients had the typical symptoms of GER, and standard esophageal tests usually yielded normal findings. Occult GER, predominantly in the upright position, appears to be common and severe in patients with chronic hoarseness, who have laryngeal lesions suggestive of GER. The causative mechanisms are not clear. The 24-h esophageal pH monitor is useful in screening this potentially treatable problem.

Ambulatory 24-hour esophageal pH monitoring. Reproducibility and variability of pH parameters

If 24-hour esophageal pH monitoring is to be a useful diagnostic tool, it must reliably discriminate gastroesophageal reflux patients despite daily variations in distal esophageal acid exposure. To address this issue, we studied 53 subjects (14 healthy normals, 14 esophagitis patients, and 25 patients with atypical symptoms) with two ambulatory pH tests performed within 10 days of each other. Intrasubject reproducibility of 12 pH parameters to discriminate the presence of abnormal acid reflux was determined. As a group, the parameters of percent time with pH less than 4 (total, upright, recumbent) were most reproducible (80%). Therefore, a subject was defined as having gastroesophageal reflux disease if at least one of these three values were abnormal. Intrasubject reproducibility for the diagnosis of reflux disease was 89% for the entire sample. Among subsets, the reproducibility was 93% for the normals and esophagitis patients and 84% for the atypical symptom patients. Total percent time with pH less than 4 was the single most discriminate pH parameter (85%) and nearly equaled that of the three combined parameters (89%). The intrasubject variability of this parameter was determined by the mean +/- 2 SD of the relative differences between the two test results for all 53 subjects. Total percent time with pH less than 4 may vary between tests by a factor of 3.2-fold or less (218% higher to 69% lower). We conclude: (1) ambulatory 24-hr esophageal monitoring is a reproducible test for the diagnosis of gastroesophageal reflux disease; and (2) the large intrastudy variability in 24-hr total acid exposure may limit this test's usefulness as a measurement of therapeutic improvement.

The symptom index: a clinically important parameter of ambulatory 24-hour esophageal pH monitoring

Ambulatory 24-h esophageal pH monitoring is an accurate quantitative test of gastroesophageal reflux (GER). However, it does not answer the question: are the patients' symptoms due to GER? We developed a numerical scale to quantify the percent association between symptoms and pH less than 4--the symptom index (SI). In 100 consecutive patients with heartburn or chest pain, the SI for the chief complaint was either high (greater than 75%) or low (less than 25%) in 77% of cases. A similar bimodal distribution was seen when heartburn or chest pain symptoms were individually evaluated. There was a good association between high SI and the presence of GER (97.5%), as well as low SI and a normal 24-h pH study (81.1%). Endoscopy was normal in 89.5% of patients with low SI, but patients with high SI had esophagitis in only 69.7% of cases. The Bernstein test showed a poor association with the SI. Therefore, the SI gives clinically relevant information regarding the role of acid reflux and patient's symptoms. We believe this simple calculated index should be included in the analysis of 24-h esophageal pH studies.

Diffuse hepatocellular dysplasia and carcinoma associated with the Mmalton variant of alpha 1-antitrypsin

The cirrhosis and hepatocellular carcinoma associated with alpha 1-antitrypsin deficiency has been exclusively reported with the PI Z allele. We present a 63-yr-old white man with emphysema, cirrhosis, and hepatocellular carcinoma. The latter occurred on a background of diffusely distributed hepatocellular dysplasia. Serum protein electrophoresis suggested a deficiency of alpha 1-antitrypsin quantitated at 13% of normal. PI phenotyping showed that he had only the rare PI Mmalton allele, previously associated only with severe lung disease. Family studies demonstrated the distribution of this rare allele. The liver at autopsy displayed well-differentiated hepatocellular carcinoma in addition to alpha 1-antitrypsin deposits in normal, dysplastic, and malignant cells.

Reye's syndrome in adults. A case report and review of the literature

Adult Reye's syndrome (ARS) is an infrequently diagnosed condition that typically affects patients younger than age 35 years. We describe a 61-year-old man with ARS occurring after influenza B-USSR infection and aspirin use. The diagnosis of ARS was confirmed by oil-red-O stain of liver biopsy tissue and subsequent electron microscopy. We review the literature on ARS and compare the clinical features and management of ARS with pediatric Rye's syndrome. This case is of interest to practitioners treating adult patients because it demonstrates that the patient population at risk for Reye's syndrome is broader than generally believed.