A Study to Evaluate the Efficacy and Safety of TAK-906 in Adult Participants With Symptomatic Idiopathic or Diabetic Gastroparesis

The drug being tested in this study is called TAK-906. TAK-906 is being tested to treat
people who have symptomatic idiopathic or diabetic gastroparesis.

The study will enroll approximately 280 patients. Participants will be randomly assigned (by
chance, like flipping a coin) to one of the four treatment groups (in 1:1:1:1 ratio) which
will remain undisclosed to the patient and study doctor during the study (unless there is an
urgent medical need):

TAK-906 Maleate 5 mg TAK-906 Maleate 25 mg TAK-906 Maleate 50 mg Placebo (dummy inactive
pill) - this is a capsule that looks like the study drug but has no active ingredient

All participants will be asked to take one capsule twice daily, at approximately the same
time each day throughout the study.

This multi-center trial will be conducted worldwide. The overall study duration is
approximately 17 weeks. Participants will make multiple visits to the clinic, and will be
contacted by telephone 40 days after receiving their last dose of study drug for a follow-up
assessment.

Inclusion Criteria:

1. Should have experienced symptoms of gastroparesis (e.g., postprandial fullness,
nausea, vomiting, upper abdominal pain, and early satiety for at least 3 months before
screening as assessed by a physician.

2. Should have confirmed delayed gastric emptying at Screening; delayed gastric emptying
by gastric emptying breath test (GEBT) is defined as t1/2 ≥79 minutes (80th
percentile).

3. Must have an average composite ANMS GCSI-DD symptom score ≥2 during the 7 days before
randomization. The predominant symptom experienced by participants must not be
abdominal pain.

4. Must experience nausea: nausea subscale (of ANMS GCSI-DD) symptom score ≥2 at least 4
of 7 days or an average nausea subscale symptom score ≥2 during the 7 days before
randomization. Nausea symptoms must not be attributable to a central disorder (e.g.
motion sickness, glaucoma, menstrual cycles, migraine headache).

5. Has a body mass index (BMI) of ≥19 to ≤40 kg/m^2 inclusive

6. Participant with diabetes mellitus must have glycosylated hemoglobin (HbA1c) ≤11% at
screening and before randomization.

Exclusion Criteria:

1. Known secondary causes of gastroparesis including but not limited to Parkinson
disease, cancer, viral illness, or connective tissue diseases.

2. Predominant gastroparetic symptom is epigastric pain, diffuse abdominal pain, or pain
associated with bowel movement.

3. Is taking medications that affect gastric emptying including opioids, glucagon-like
peptide-1 analogs (e.g., exenatide, liraglutide), amylin analogs (e.g., pramlintide),
and cannabinoids.

4. Prior history of gastric surgery, including but not limited to gastrectomy, gastric
bypass, gastric banding, bariatric surgery, pyloroplasty, vagotomy, or fundoplication,
which has manipulated the natural anatomy of the stomach.

5. History of intra-pyloric botulinum toxin injection within 3 months of Screening or
currently has functioning implantable electric stimulator.

6. Nasogastric, percutaneous endoscopic gastrostomy, or percutaneous endoscopic
jejunostomy feeding tube or inpatient hospitalization for gastroparesis within 2 weeks
before the Screening Visit.

7. Required parenteral nutrition for treatment of gastroparesis within 2 months before
the Screening Visit.

8. Previous diagnosis of gastric bezoar (the presence of retained liquid, bile, or small
amounts of poorly organized food residue is permitted).

9. Poor control of diabetes within 30 days prior to randomization, including diabetic
ketoacidosis, hypoglycemia requiring medical intervention, admission for control of
diabetes or diabetic complications

10. Elevated serum prolactin (>upper limit of normal [ULN]) at Screening Visit 2.

11. Has concurrent hypogonadism, current clinically significant menstrual abnormalities,
such as amenorrhea or oligomenorrhea, or other clinical features of hyperprolactinemia
such as galactorrhea or gynecomastia.

12. Uncontrolled or poorly controlled medical or psychiatric comorbidities which might
affect their ability to participate in the study.