Dukes, George E.

SummaryBackgroundGastroparesis is defined by delayed gastric emptying with associated symptoms in the absence of mechanical obstruction.AimTo evaluate pharmacokinetics and pharmacodynamics of felcisetrag, a highly selective 5‐HT4 receptor agonist, on total gut transit in patients with documented delayed gastric emptying of solids.MethodsSingle‐centre, placebo‐controlled study of 36 participants receiving placebo, 0.1mg, 0.3mg or 1.0mg of felcisetrag I.V. infusion, daily, for 3 days. At baseline, each participant completed a 4h, 99mTc‐egg meal (300 kcal, 30% fat) gastric emptying test. Following infusion (Day 2), gastric, small bowel and colonic transit of solids were measured over 48h (same meal plus 111In‐charcoal delivered in methacrylate‐coated capsule). Samples were collected for pharmacokinetics. The primary endpoint was gastric emptying T1/2. Statistical analysis used baseline parameters as covariates (ANCOVA).ResultsPatients (22 idiopathic, 14 diabetic gastroparesis) were randomised to felcisetrag (0.1 mg, n = 10; 0.3 mg, n = 9; 1.0 mg, n = 7) or placebo (n = 10). Compared to placebo, felcisetrag significantly accelerated gastric emptying T1/2, colonic filling at 6h, and 10% small bowel transit time (overall P < 0.01; all three doses individually Bonferroni corrected P < 0.05) for all three measurements. Ascending colon emptying (T1/2) was significantly accelerated (all doses), and colonic transit at 48 hours was accelerated with 0.1 mg and 0.3 mg felcisetrag compared to placebo. Pharmacokinetic results were dose proportional. Felcisetrag was well tolerated with no clinically significant findings from clinical laboratory, vital signs or ECG.ConclusionI.V. felcisetrag significantly accelerated gastric, small bowel and colonic transit in patients with gastroparesis, and should be further evaluated for short‐term treatment of gastric and intestinal motility disorders.ClinicalTrials.gov #NCT03281577

SummaryBackgroundGastroparesis is a chronic gastric motility disorder. Dopamine D2/D3 receptor antagonists metoclopramide and domperidone are current treatment options but are associated with central nervous system and cardiovascular safety concerns, respectively, precluding chronic use. Trazpiroben (TAK‐906), a dopamine D2/D3 receptor antagonist, is under development for chronic treatment of moderate‐to‐severe gastroparesis. Nonclinical data suggest trazpiroben will have D2/D3 receptor antagonism comparable with metoclopramide or domperidone.AimsTo evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics (effect on prolactin and gastric function) of twice‐daily trazpiroben (5, 25 and 100 mg) in participants with gastroparesis.MethodsThis phase 2a pilot study evaluated gastric emptying using the gastric emptying breath test, with metoclopramide as an internal control. Gastric accommodation and gastroparesis symptoms were assessed using the nutrient drink test and American Neurogastroenterology and Motility Society Gastroparesis Cardinal Symptom Index‐Daily Diary, respectively.ResultsOverall, 51 participants were enrolled. Trazpiroben was well tolerated, demonstrating a favourable safety profile without cardiovascular or central nervous system adverse events. All trazpiroben doses were rapidly absorbed and eliminated (t1/2z 4‐5 hours), and D2/D3 receptor target engagement confirmed by increased serum prolactin (peaking at trazpiroben 25 mg). No effect on gastric emptying was demonstrated with trazpiroben or metoclopramide (P > 0.05), although benefits in volume‐to‐fullness were seen at trazpiroben 5 mg (P > 0.05) and 25 mg (88.5 vs −26.3 mL; P = 0.019), and nonsignificant numerical aggregate symptom score improvements were observed with trazpiroben 25 mg vs placebo (P = 0.182).ConclusionsTrazpiroben was well tolerated with a favourable safety profile, supporting its further development for the treatment of gastroparesis. ClinicalTrials.gov identifier: NCT03268941.