• Changed Inclusion Criterion #10 to clarify the concomitant medications restriction for entry to the study as well as the use of concomitant medications that affect gastroparesis symptoms in order for symptoms to remain stable throughout the study. • Added Exclusion Criterion #12 to exclude participants with an underlying condition that may have been the cause of the gastroparesis. • Added 2 new study endpoints: the proportion of participants with at least 1-point improvement from baseline in the GCSI-DD and GRS individual components at each week (1-12) to further assess changes. • Added predose and postdose 12-lead electrocardiograms (ECGs) to Visit 7 (Day 56) to closely monitor participants’ cardiac health while they were being dosed. • Added HbA1c sample collection to Visit 8 (Day 84) for diabetic participants to monitor the results for these participants from Screening to the end of the study to determine effect of the study drug. • Added blinded interim assessment of sample size assumptions to ensure an adequate sample size. • Added a statement that the proportion endpoints would be evaluated using chi-square methodology. • Changed the PK assessment at Visit 7 (Day 56) from serial pharmacokinetics (PK) sampling to a trough level and at Visit 8 (Day 84) from a trough level to serial PK sampling to better correlate blood levels with gastric motility breath test (GMBT) results. • Added a statement that the final interpretation of all ECGs collected during the study would be completed by a central reviewer. • Removed or changed certain statements related to abstaining from smoking and alcohol and strenuous exercise to clarify these requirements in relationship to gastric motility breath test (GMBT) or GES testing. • Clarified that the GES was not required if a participant had a comparable, qualifying 4-hour GES performed within 1 year of Screening.

• Clarified details of the study design (added the Screening Treatment Satisfaction Questionnaire, clarified the description of the 2 daily PRO measures, added that participants must have had a 7-day mean score of ≥2.5 and <5 points on the GCSI-24H at Day 1 and that eligible participants completed the Patient Assessment of Upper Gastrointestinal Quality of Life (PAGI-QOL) questionnaire to establish baseline QOL metrics at Day 1) for consistency between the study procedures section and the Schedule of Study Procedures. • Added the use of comparable, qualifying 4-hour 99mTc GES within 1 year of Screening to decrease participants’ exposure to radiation and decrease the number of long visits required by the protocol. The GES was used to diagnose participants with delayed gastric emptying and the Sponsor did not believe a confirmatory test was needed if a GES was performed within 1 year of Screening. • Added a statement that at least 50% of the participantsenrolled must have had a GES performed during the Screening Period of the study to allow the Sponsor to assess any difference in treatment effect due to historical GES (within 1 year of Screening) compared to the GES performed at the time of study entry. • Changed the GCSI-2W composite score range for eligibility to between ≥2 and <5 to enlarge the pool of participants eligible for Screening. Also revised the GCSI-DD to GCSI-24H for consistency with the naming convention of the questionnaire. • Removed all references to the 13C-octanoate GMBT. The GMBT was removed from the study to decrease the number of long visits and the study burden for participants as well as streamline study procedures for study sites. • Deleted references to GE t1/2 using 99mTc GES since the GMBT was removed from the study. • Added a statement that participants also completed the PAGI-QOL questionnaire to assess QOL metrics and completed the Treatment Satisfaction Question to provide an impression of study treatment.

Continuation of protocol amendment 2: • Changed the serial PK assessments to a substudy. Decreasing the serial PK sampling to a subset of participants allowed participants who were unable to stay for numerous long visits to participate in the study. The trough PK sample at Day 14 was deleted, as it was the only blood draw for the visit and sufficient PK data were collected using the remaining PK samples. • Changed Inclusion Criterion #7 to increase the BMI range from 18 to 35 kg/m^2 to 18 to 42 kg/m^2, inclusive. • Changed Inclusion Criterion #11 (and revised similar language globally) to decrease the period for abstaining from prohibited medications from 72 hours to 24 hours prior to GES during Screening and start of Baseline Period to be less restrictive to potential participants, and to clarify that certain medications could have been used but their use was documented during the study in the Treatment and Follow-Up Periods so that participants did not withhold treatment for an extended period. • Added text to clarify that Visit 2 could have been combined with Screening if a Screening GES was not needed. • Changed the following inclusion/exclusion criteria to allow more potential participants to screen for the study: o Changed Exclusion Criterion #3 to allow a type 1 or type 2 diabetic to have an HbA1c level >11% instead of >10%. o Changed Exclusion Criterion #6 to allow a history of intrapyloric botulinum toxin injection within 3 months instead of 6 months of Screening. o Changed Exclusion Criterion #10 to allow a history of eating disorder but not a concurrent eating disorder. o Changed Exclusion Criterion #14 to exclude participants who were unwilling or unable to perform 99mTc GES, if applicable, for consistency with global removal of GMBT from the study. o Changed Exclusion Criterion #15 to increase the upper limit of normal for aspartate aminotransferase and alanine aminotransferase from >1.5 times to >2 times the upper limit of normal.

Continuation of protocol amendment 2: o Changed Exclusion Criterion #16 and concomitant medications language to clarify the use of opioids, with the intention to exclude chronic opioid use but not restrict or prohibit use of opioids for potential AEs. o Changed Exclusion Criterion #18 and concomitant medications language to clarify the use of moderate P-gp inhibitors based on the Sponsor’s assessment that the risk of moderate inhibitors and inducers was anticipated to be relatively low. o Deleted Exclusion Criterion #19 and modified concomitant medications language that prohibited the use of 2 or more psychotropic medications to be less restrictive to potential participants. o Changed Exclusion Criterion #21 to clarify examples of psychiatric conditions that were exclusionary. • Deleted Visit 3 from the study since the primary purpose of this visit was to conduct the GMBT; all Visit 3 procedures were moved to Visit 4. • Clarified the allowable window for the postdose ECGs and increased certain visit windows to allow more flexibility in scheduling visits to accommodate participants. • Added follow-up telephone calls on Day 42 and Day 70 in the Schedule of Study Procedures for clarity and consistency with the study procedures section. • Updated the total amount of blood drawn if participating in the main study only, and if also participating in the PK substudy. • Added predose meal requirements for Visit 5 (Day 14) and Visit 7 (Day 56) and postdose meal requirements for Visit 6 (Day 28) and Visit 8 (Day 84) for consistency with the Schedule of Study Procedures.

• Added a 4-hour gastric emptying breath test (GEBT) option during the Screening Period to allow for a nonradioactive alternative for gastric emptying testing. • Clarified that a participant could qualify for the study with either a GES or a GEBT, and added text to allow for an additional GEBT at Screening for qualification if needed. • Changed Inclusion Criterion #6 to define entry criteria for the GEBT results that qualified the participant for the study, and to allow a participant to perform a second gastric emptying test if they failed either the GES or GEBT at Screening. • Changed Exclusion Criterion #13 and study procedures language to add additional exclusions pertaining to nicotine-containing products specific for the GEBT. • Changed Exclusion Criterion #14 to add additional exclusions for the GEBT (allergies to lactose and Spirulina). • Changed Exclusion Criterion #23 to clarify which drugs in the urine drug screen were exclusionary. • Broadened the study endpoints to include both the GES and the GEBT. • Increased certain visit windows to increase participant compliance with the scheduled visits per protocol. • Clarified that the Follow-up Visit was to occur 14 days after the Day 84/Early Termination Visit. • Added cannabinoids and tramadol to urine drug screen testing. • Clarified which participants would be included in the full analysis set and included new variables added to the protocol in the subgroup analysis.