Effect of Ticagrelor vs. Placebo in the Reduction of Vaso-occlusive Crises in Pediatric Patients With Sickle Cell Disease

A painful crisis is an onset or worsening of pain that lasts at least 2 hours, for which there is no explanation other than vaso-occlusion and which requires therapy with oral or parenteral opioids, parenteral non-steroidal anti-inflammatory drugs, or other analgesics prescribed by a healthcare provider in a medical setting (such as a hospital, clinic or emergency room visit) or at home. Events with an onset date <=7 days of the previous event onset date are not counted as new events.

The ACS is an acute illness characterized by fever and/or respiratory symptoms, accompanied by a new pulmonary infiltrate on a chest X-ray. Events with an onset date <=7 days of the previous event onset date are not counted as new events.

The duration of painful crises is defined as the sum of the duration of painful crises experienced by a participant over the defined treatment period. If two or more events have overlapping durations, the overlapping days were counted only once.

The number of VOC events requiring hospitalization or emergency department visits is defined as the count of VOC events experienced by a participant over the treatment period, for which the primary setting for VOC treatment was in-patient hospitalization or emergency department. Events with an onset date <=7 days of the previous event onset date are not counted as new events.

The number of days hospitalized for all individual VOC events experienced by a participant during the treatment period is defined as the sum of the duration of all individual hospitalizations (taking into account potential overlapping hospitalization days of VOC components) during VOC events experienced by a participant over the treatment period for which the primary setting for VOC treatment was in-patient hospitalization.

The number of acute SCD complications is defined as the count of all individual acute SCD complications experienced by a participant over the treatment period. Acute SCD complications are defined as any one or more of the following individual complications: Transient ischaemic attack/ischaemic stroke, hepatic sequestration, splenic sequestration, priapism, and dactylitis.

The number of days hospitalized for acute SCD complications is defined as the sum of the duration of all individual hospitalizations (taking into account potential overlapping hospitalization days) due to acute SCD complications experienced by a participant over the treatment period, for which hospitalization was reported.

The number of participants with at least one sickle cell-related RBC transfusion reported. Adverse events resulting in the need for RBC transfusions were captured prior to database lock to determine if the transfusion was sickle cell-related or not.

The PedsQL SCD module instrument developed using a 5-point Likert scale (where 0= never and 4= almost always) for the participant self-report forms for ages ≥5 to <8 years, ≥8 to <13 years, and ≥13 to ≤18 years and the caregiver proxy-report form specific for ≥2 to <5 years was used. The PedsQL SCD module measures problems in the following categories:

• Pain: 3 sub-scales
• Worry: 2 sub-scales
• Emotions: 1 sub-scale
• Treatment: 1 sub-scale
• Communication: 2 sub-scales
• Total score PedsQL SCD module items were reverse-scored and linearly transformed to a 0 to 100 scale (0= 100, 1= 75, 2= 50, 3= 25, 4= 0) so that higher scores indicate better quality of life. To create the PedsQL SCD module total score (43/42/40 items - depending on version completed) the arithmetic mean of the transformed scores was computed as the sum of the items transformed scores divided by the number of items answered. Baseline values are the closest observation prior to and including the randomization visit.

The PedsQL multidimensional fatigue scale instrument developed using a 5-point Likert scale (where 0= never and 4= almost always) for the participant self-report forms for ages ≥5 to <8 years, ≥8 to <13 years, and ≥13 to ≤18 years and the caregiver proxy-report form specific for ≥2 to <5 years was used. The PedsQL multidimensional fatigue scale measures problems in the following categories:

• General (6 items)
• Sleep/rest (6 items)
• Cognitive fatigue (6 items)
• Total score (18 items) PedsQL multidimensional fatigue scale items were reverse-scored and linearly transformed to a 0 to 100 scale (0= 100, 1= 75, 2= 50, 3= 25, 4= 0) so that higher scores indicate better quality of life. To create the PedsQL multidimensional fatigue scale total score (18 items), the arithmetic mean of the transformed scores was computed as the sum of the items transformed scores divided by the number of items answered. Baseline values are closest observation prior to and including randomization visit.

For participants attending school/work at randomization, absence from school/work due to SCD was recorded weekly by the participant in the eDevice with the help of the caregiver if needed. The percentage of days absent from school/work due to SCD in the defined treatment period was calculated as follows:

Percentage of absent days = (total number of days reported)/(total number of questionnaires answered ×7).

The Face, Legs, Activity, Cry, Consolability (FLACC) scale is caregiver-reported and used to assess pain daily during the VOC event for those participants <5 years of age as determined at randomization. Each of the 5 behaviours observed are assigned a score of 0, 1 or 2. The total FLACC score ranges between 0 and 10, with 0 representing "no pain" and 10 representing "very much pain". Lower score indicate better outcome. Worst pain ratings were collected once daily throughout the duration of the VOC event using an eDevice.

The Faces Pain Scale-revised (FPS-R) was administered to assess pain daily during the VOC event by those participants aged ≥5 years as determined at randomization. The FPS-R consists of 6 faces and scoring ranges between 0 and 10 (with an increase in numeric value by 2), where 0 is "no pain" and 10 is "very much pain". Lower score indicate better outcome. Worst pain ratings were collected once daily throughout the duration of the VOC event using an eDevice.

Analgesics use (opioid and non-opioid) during VOC events.

Response to palatability was assessed through the SMPA question "Was any behaviour observed when the study medication was given to this participant that would be indicative of a negative response to the palatability of the study medication?". This was presented as a binary outcome (that is, where "No" is no negative response and "Yes" is negative response). No negative response was considered as a positive outcome.

An observer's assessment of the participant's behaviour using the SMPA was performed for all participants taking the study treatment who are 2 to 4 years of age. Willingness to swallow was assessed and categorized as follows:

• Swallowed without a problem
• Some resistance but did swallow
• Spit out some/all of the medication
• Vomited up the medication. The category "swallowed without a problem" was considered as positive outcome.

The FHS method was used for all participants taking the study treatment who are ≥5 years of age. The FHS consists of 5 faces with descriptions ranging from "Dislike very much" to "Like very much". The face with description "Like very much" was considered as positive outcome. The way in which the study treatment was taken, that is, whether the tablet is whole or dispersed, was captured.