Safety, tolerability, and activity of ALV003: results from two phase 1 single, escalating-dose clinical trials.

BACKGROUND: Celiac disease is the most common hereditary autoimmune disease in humans. The only treatment option for non-refractory celiac disease patients is adherence to a strict life-long gluten-free diet, which often fails to normalize small bowel histology. ALV003 is a mixture of two proteases that degrades gluten and is in clinical development as an oral therapy for patients with celiac disease. AIMS: The safety, tolerability, and activity of ALV003 were assessed in two phase 1 clinical trials. METHODS: In study 1 (N = 28) the study drug was administered in the fasted state; in study 2 (N = 53) the study drug was administered together with a gluten-containing meal. Both studies were single-dose, single-blind, placebo-controlled, cross-over trials. ALV003 was dosed at escalating dose levels by cohort (100, 300, 900, and 1,800 mg) and gastric samples were aspirated using a nasogastric tube. Adverse events, serum drug levels, and anti-drug antibody titers were measured. Gastric samples were assessed for ALV003 enzymatic activity over time (gastric pharmacokinetics) and gluten degradation (gastric pharmacodynamics). RESULTS: All doses were well tolerated, and no serious adverse events or allergic reactions were observed. Gastric aspirates collected 30 min following a meal showed that 100 and 300 mg ALV003 degraded 75 ± 10% (N = 8) and 88 ± 5% (N = 8), respectively, of one gram of wheat bread gluten. CONCLUSIONS: ALV003 is an orally active protease that appears to be stable in the fed stomach and degrades dietary gluten in this compartment. Single doses of oral ALV003 were not associated with serious adverse reactions.

Intravenous pantoprazole as initial treatment in patients with gastroesophageal reflux disease and a history of erosive esophagitis: a randomized clinical trial.

We sought to evaluate safety and efficacy of IV pantoprazole when used as initial therapy in patients with gastroesophageal reflux disease (GERD) and a history of erosive esophagitis (EE) in a double-blind, placebo-controlled, randomized, parallel-group study. Patients were randomized to 7 days of once-daily IV or oral pantoprazole (40 mg) or placebo. Efficacy variables included maximal acid output, basal acid output, and changes from baseline in frequency/severity of GERD symptoms, and frequency of antacid usage. Seventy-eight patients were randomized (n=26/27/25 [IV/oral/placebo]). Mean maximal acid output was 8.4, 6.3, and 20.9 mEq/h for IV or oral pantoprazole, and placebo, respectively. For pantoprazole versus placebo, maximal and basal acid output were significantly lower (P<.001) and there was a numerical trend toward improved GERD and antacid usage. Both treatments were well tolerated. In conclusion, IV/oral pantoprazole were similarly effective in suppressing basal and pentagastrin-stimulated gastric acid secretion in GERD patients with a history of EE.

Inhibition of pentagastrin-stimulated gastric acid secretion by pantoprazole and omeprazole in healthy adults.

Our objective was to compare the onset and duration of a single dose of pantoprazole or omeprazole on maximally stimulated gastric acid secretion. This double-blind, randomized, placebo-controlled study involved 36 healthy adults and utilized continuous pentagastrin infusion to stimulate acid secretion after administration of pantoprazole, 40 mg, omeprazole, 20 mg, or placebo. Gastric aspirates were collected over 24 hr and analyzed for volume, pH, and hydrogen ion concentration, and gastric acid outputs (GAO) were calculated. Comparison between GAO and intragastric pH was performed. Pantoprazole resulted in significantly greater inhibition of GAO than omeprazole. Mean cumulative 24-hr GAO was 164 +/- 130 mEq for pantoprazole versus 283 +/- 159 mEq for omeprazole (P = 0.031). Pantoprazole patients reached and maintained GAO levels below the 10-mEq/hr threshold at 5.7 hr, whereas omeprazole patients never reached this threshold. We conclude that pantoprazole significantly suppressed gastric acid secretion compared to omeprazole. Comparisons between pH and GAO showed that GAO was a more appropriate measure of gastric acid secretion than intragastric pH.

Heat-stable enterotoxin of Escherichia coli stimulates a non-CFTR-mediated duodenal bicarbonate secretory pathway.

The cystic fibrosis (CF) transmembrane conductance regulator (CFTR) is an important pathway for duodenal mucosal bicarbonate secretion. Duodenal biopsies from CF patients secrete bicarbonate in response to heat-stable enterotoxin from Escherichia coli (STa) but not cAMP. To explore the mechanism of STa-induced bicarbonate secretion in CF more fully, we examined the role of CFTR in STa-stimulated duodenal bicarbonate secretion in mice. In vivo, the duodenum of CFTR (-/-) or control mice was perfused with forskolin (10(-4) M), STa (10(-7) M), uroguanylin (10(-7) M), 8-bromoguanosine 3',5'-cGMP (8-Br-cGMP) (10(-3) M), genistein (10(-6) M) plus STa, or herbimycin A (10(-6) M) plus STa. In vitro, duodenal mucosae were voltage-clamped in Ussing chambers, and bicarbonate secretion was measured by pH-stat. The effect of genistein, DIDS (10(-4) M), and chloride removal was also studied in vitro. Control, but not CF, mice produced a significant increase in duodenal bicarbonate secretion after perfusion with forskolin, uroguanylin, or 8-Br-cGMP. However, both control and CF animals responded to STa with significant increases in bicarbonate output. Genistein and herbimycin A abolished this response in CF mice but not in controls. In vitro, STa-stimulated bicarbonate secretion in CF tissues was inhibited by genistein, DIDS, and chloride-free conditions, whereas bicarbonate secretion persisted in control mice. In the CF duodenum, STa can stimulate bicarbonate secretion via tyrosine kinase activity resulting in apical Cl(-)/HCO(3)(-) exchange. Further studies elucidating the intracellular mechanisms responsible for such non-CFTR mediated bicarbonate secretion may lead to important therapies for CF.