A Study to Evaluate the Safety and Pharmacokinetics of Regadenoson in Pediatric Patients

Inclusion Criteria:

• • Male or female adolescent aged from 12 to <18 years (Cohort A) or child aged from 2 to <12 years (Cohort B) or infant aged from 1 to <24 months (Cohort C).

• Patient weighs at least 3 kg.

• Patients who need to undergo a clinically indicated pharmacologic stressperfusion CMR test and who are considered fit for a pharmacological stressperfusion CMR by the investigator. The pharmacologic stress perfusion CMR maybe performed in patients for further evaluation of cardiovascular conditions ordiseases, such as, but not limited to, Kawasaki disease, congenital heartdiseases, congenital coronary abnormalities, and post-cardiac surgery /transplantation, etc.

• Stable medication regimen for at least 7 days prior to dosing. Stable isdefined as no addition, discontinuation, or change of any medications (or theirdoses), that could alter the rate-pressure product (HR x BP).

• Patients and those whose parents or legally authorised representatives are, inthe Investigator's view, likely to be compliant and complete the study will beeligible to participate

• Post-menarchal female patients must have a negative urine pregnancy test atscreening and at pre-dose on the dosing day.

• Post-menarchal female patients must be practicing abstinence, or be using aneffective form of birth control (e.g., intrauterine device, oralcontraceptives, contraceptive implants or injections, diaphragm withspermicide, cervical cap, or consort use of condom) for at least 30 days beforebeing enrolled in the study

Exclusion Criteria:

• • Prior allergic reaction to Gd contrast agents and/or regadenoson or any componentof its formulation, or to aminophylline or to its components (ethylenediamine andtheophylline).

• Standard clinical contraindications to MRI as per institutional guidance,including patients with cochlear implants and implanted cardiac devices, orconsidered unfit for a pharmacologic stress perfusion CMR test by theinvestigator.

• All patients will be screened for eGFR within 24 hours before the exam andpatients presenting with eGFR <30 mL/min/1.73 m2 (by the Schwartz formula) willbe excluded.

• Pregnant or lactating females, or females of childbearing potential not usingan acceptable form of birth control (negative urine pregnancy test alsorequired).

• In the judgment of the Investigator, any clinically significant ongoing medicalcondition (e.g., myocardial infarction, or unstable angina within 5 days,pericardial inflammatory disease, severe cardiac outflow tract obstruction,acutely decompensated heart failure, uncontrolled epilepsy, high risk forseizures, etc.) or clinically significant laboratory abnormality that isconsidered to potentially jeopardise the patient's safety.

• Patients with 2nd or 3rd degree atrioventricular block or sick sinus syndromewith or without an artificial pacemaker.

• Known or suspected bronchoconstrictive and bronchospastic lung disease eitherbeing unstable or requiring active treatment (e.g., wheezing noted on physicalexam, frequent exacerbations or active treatment with a bronchodilator orcorticosteroids).

• Out of acceptable range sitting or semi-recumbent resting BP or HR (beats perminute [bpm]) at screening as provided below:

1. Acceptable range for BP (systolic / diastolic mmHg):

• For Cohorts A and B: 85-130 / 45-90

• For Cohort C: 80-120 / 40-80 b) Acceptable range for HR:

• For Cohort A: 55 to 100 bpm

• For Cohort B: 60 to 120 bpm

• For Cohort C: 70 to 160 bpm

• Use of any experimental or investigational drug or device within 30 days priorto dosing with study drug

• Consumption of methylxanthine-containing products such as caffeinated coffee,tea, caffeinated soft drinks, cocoa or chocolate in the 48 hours prior todosing

• Aminophylline or theophylline use within 24 hours, dipyridamole use within 48hours prior to dosing.

• History of alcohol abuse or drug addiction, as determined by the Investigator

• Currently smokes more than 5 cigarettes or equivalent per day, and if eligiblefor the study, would not be able to abstain from smoking from midnight prior todosing until the end of the study period

• Positive urine drug screen at the screening visit, including amphetamines,barbiturates, cannabinoids, cocaine, ethanol and opiates. This will beperformed for all patients in Cohort A and those patients at age-appropriaterisk in Cohorts B and C, as determined by the investigator.

Note: If the patient is currently receiving prescribed medications containing any of these ingredients, re-screening can only be considered if found acceptable based on the best medical judgement of the investigator and after discussion with the medical monitor. Otherwise, patients with a positive urine drug test will be considered a screen failure.