The Efficacy of Tradipitant in Patients With Diabetic and Idiopathic Gastroparesis in a Phase 3 Randomized Placebo-Controlled Clinical Trial

BACKGROUND

Neurokinin receptor 1 antagonists are effective in reducing nausea and vomiting in chemotherapy-induced emesis. We investigated the safety and efficacy of tradipitant, a neurokinin receptor 1 antagonist, in patients with idiopathic and diabetic gastroparesis.

METHODS

A total of 201 adults with gastroparesis were randomly assigned to oral tradipitant 85 mg (n = 102) or placebo (n = 99) twice daily for 12 weeks. Symptoms were assessed by a daily symptom dairy, Gastroparesis Cardinal Symptom Index scores, and other patient-reported questionnaires. Blood levels were monitored for an exposure-response analysis. The primary outcome was change from baseline to week 12 in average nausea severity, measured by daily symptom diary.

RESULTS

The intention-to-treat (ITT) population did not meet the prespecified primary endpoint at week 12 (difference in nausea severity change drug vs placebo; P = .741) or prespecified secondary endpoints. Post hoc analyses were performed to control for drug exposure, rescue medications, and baseline severity inflation. Subjects with high blood levels of tradipitant significantly improved average nausea severity beginning at early time points (weeks 2-4). In post hoc sensitivity analyses, tradipitant treatment demonstrated strengthened effects, with statistically significant improvements in nausea at week 12.

CONCLUSIONS

Although tradipitant did not reach significance in the ITT population, a pharmacokinetic exposure-response analysis demonstrated significant effects with adequate tradipitant exposure. When accounting for confounding factors such as baseline severity inflation and rescue medication, a statistically significant effect was also observed. These findings suggest that tradipitant has potential as a treatment for the symptom of nausea in gastroparesis. (ClincialTrials.gov, Number: NCT04028492).

Clinical trial: a single-centre, randomised, controlled trial of tradipitant on satiation, gastric functions, and serum drug levels in healthy volunteers

BACKGROUND

Tradipitant, an NK1 receptor antagonist, improved symptoms in patients with gastroparesis. It is unclear whether these effects are mediated centrally (e.g., vomiting centre) or on gastric functions. As a class, NK1 antagonists may retard gastric emptying (GE) or increase fasting and postprandial gastric volumes (GV).

AIM

To evaluate the effects of tradipitant relative to placebo on gastric motor functions, satiation, postprandial symptoms, and pharmacokinetics.

METHODS

We conducted a randomised, double-blind, placebo-controlled, single-centre study of tradipitant 85 mg or matching placebo b.i.d. for 9 consecutive days in 24 healthy volunteers. During the last 2 days of treatment, participants underwent scintigraphic measurements of GE of 320 kcal egg meal, fasting and postprandial GV by SPECT, and satiation by nutrient drink ingested to maximum tolerated volume (MTV) and symptoms 30 min later. Treatments were compared by Wilcoxon rank sum test. The study had 80% power to detect group differences of 23.6% in GV and 29.2% in GE T_1/2 .

RESULTS

The two groups of healthy participants were well balanced based on demographic features, age, and BMI. There were nonsignificant positive correlations between blood levels of tradipitant and accommodation GV and GE at 4 h. There were no significant effects of tradipitant, 85 mg b.i.d. for 9 days compared to placebo on GE, GV, satiation, or symptoms 30 min after MTV.

CONCLUSION

Tradipitant, 85 mg b.i.d., does not significantly affect gastric motor functions (GV or GE). Importantly, there was no retardation of GE by tradipitant, which is important in relation to its potential use in patients with gastroparesis.

CLINIC TRIALS REGISTRY

ClinicalTrials.gov #NCT04849559.

Enrichment of Motilin Receptor Loss-of-Function Variants in Gastroparesis

INTRODUCTION

Gastroparesis is a serious medical condition characterized by delayed gastric emptying and symptoms of nausea, vomiting, bloating, fullness after meals, and abdominal pain.

METHODS

To ascertain the genetic risk factors for gastroparesis, we conducted the largest thus far whole-genome sequencing study of gastroparesis. We investigated the frequency and effect of rare loss-of-function variants in patients with both idiopathic and diabetic gastroparesis enrolled in a clinical study of gastroparesis.

RESULTS

Among rare loss-of-function variants, we reported an increased frequency of a frameshift mutation p.Leu202ArgfsTer105, within the motilin receptor gene, variant rs562138828 (odds ratio 4.9). We currently replicated this finding in an independent large cohort of gastroparesis samples obtained from patients participating in the ongoing phase III gastroparesis clinical study.

DISCUSSION

Motilin receptor is an important therapeutic target for the treatment of hypomotility disorders. The identified genetic variants may be important risk factors for disease as well as may inform treatments, especially those targeting motilin receptor.

Efficacy and Safety of Tradipitant in Patients With Diabetic and Idiopathic Gastroparesis in a Randomized, Placebo-Controlled Trial

BACKGROUND & AIMS

Treatments are needed for gastroparesis; antagonists of tachykinin receptor 1 (TACR1, also called NK1R) can reduce symptoms of nausea and vomiting. We investigated the safety and efficacy of tradipitant, an antagonist of NK1R, in patients with idiopathic or diabetic gastroparesis.

METHODS

We performed a double-blind trial of 152 adults with gastroparesis at 47 sites in the United States from November 2016 through December 2018. Participants were randomly assigned to groups given oral tradipitant 85 mg (n = 77) or placebo (n = 75) twice daily for 4 weeks. Symptoms were assessed by a daily symptom dairy, Gastroparesis Cardinal Symptom Index scores, and other patient-reported questionnaires. The primary outcome from the intent-to-treat analysis was change from baseline to week 4 in average nausea severity, measured by the Gastroparesis Core Symptom Daily Diary.

RESULTS

Patients receiving tradipitant had a significant decrease in nausea score (reduction of 1.2) at week 4 compared with placebo (reduction of 0.7) (P = .0099) and a significant increase in of nausea-free days at week 4 (28.8% increase on tradipitant vs 15.0% on placebo; P = .0160). Patients with nausea and vomiting at baseline (n = 101) had an even greater decrease in nausea in when given tradipitant (reduction of 1.4) compared with those given placebo (reduction of 0.4) (P < .0001), as well as an increase in nausea-free days at week 4 (32.3% improvement on tradipitant vs 7.6% on placebo; P = .0003). The average nausea score was 1 or less at week 4 in 32.9% of patients given tradipitant compared with 11.8% of patients given placebo (P = .0013). A greater than 1-point improvement in Gastroparesis Cardinal Symptom Index score was observed in 46.6% of patients given tradipitant compared with 23.5% of patients given placebo (P = .0053).

CONCLUSIONS

Tradipitant resulted in statistically and clinically meaningful improvements in nausea and reduced vomiting, compared with placebo, in patients with idiopathic or diabetic gastroparesis. ClinicalTrials.gov, Number: NCT02970968.

Voluntary exercise blocks Western diet-induced gene expression of the chemokines CXCL10 and CCL2 in the prefrontal cortex

Obesity increases inflammation, both peripherally and centrally, and exercise can ameliorate some of the negative health outcomes associated with obesity. Within the brain, the effect of obesity on inflammation has been well characterized in the hypothalamus and hippocampus, but has been relatively understudied in other brain regions. The current study was designed to address two primary questions; (1) whether western diet (high fat/high sucrose) consumption would increase markers of inflammation in the prefrontal cortex and (2) whether concurrent voluntary wheel running would ameliorate any inflammation. Adult male mice were exposed to a western diet or a control diet for 8weeks. Concurrently, half the animals were given running wheels in their home cages, while half did not have access to wheels. At the conclusion of the study, prefrontal cortex was removed and expression of 18 proinflammatory genes was assayed. Expression of a number of proinflammatory molecules was upregulated by consumption of the western diet. For two chemokines, chemokine (C-C motif) ligand 2 (CCL2) and C-X-C motif chemokine 10 (CXCL10), voluntary exercise blocked the increase in the expression of these genes. Cluster analysis confirmed that the majority of the tested genes were upregulated by western diet, and identified another small cluster of genes that were downregulated by either diet or exercise. These data identify a proinflammatory phenotype within the prefrontal cortex of mice fed a western diet, and indicate that chemokine induction can be blocked by voluntary exercise.