Lexiscan

Name: Lexiscan

What is regadenoson?

Regadenoson is a stress agent that works by increasing blood flow in the arteries of the heart.

Regadenoson is given in preparation for a radiologic (x-ray) examination of blood flow through the heart to test for coronary artery disease.

Regadenoson may also be used for purposes not listed in this medication guide.

Lexiscan Dosage and Administration

Administration

IV Administration

Administer by rapid (i.e., over approximately 10 seconds) IV injection into a peripheral vein.1 Use 22-gauge or larger catheter or needle.1

After injection, immediately flush with 5 mL of 0.9% sodium chloride injection.1

Administer radionuclide myocardial perfusion imaging agent 10–20 seconds after flush; may inject radionuclide directly into same catheter as regadenoson.1 3 9

Some clinicians suggest BP monitoring every minute during infusion and 3–5 minutes into recovery.3 ECG monitoring also recommended.3

Rate of Administration

Administer over approximately 10 seconds.1

Dosage

Adults

Radionuclide Myocardial Perfusion Imaging IV

0.4 mg (5 mL).1 3 9 (See Administration under Dosage and Administration.)

Special Populations

Hepatic Impairment

Dosage adjustment not necessary.1 6 9

Renal Impairment

Dosage adjustment not necessary.1 6 9

Geriatric Patients

Dosage adjustment not necessary.1 6 9

Lexiscan Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

More common
  • Arm, back, or jaw pain
  • chest pain or discomfort
  • difficult or labored breathing
  • fast or irregular heartbeat
  • nausea
  • sweating
  • tightness in the chest
Incidence not known
  • Confusion
  • difficulty swallowing
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • fainting
  • irregular heartbeat recurrent
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • rash, hives, or itching skin
  • trembling or shaking of the hands or feet
  • unusual tiredness or weakness

Get emergency help immediately if any of the following symptoms of overdose occur:

Symptoms of overdose
  • Dizziness
  • feeling of warmth
  • increased heart rate
  • redness of the face, neck, arms, and occasionally, upper chest

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Headache
Less common
  • Change in taste
  • loss of taste
  • stomach soreness or discomfort
Incidence not known
  • Diarrhea
  • difficulty with moving
  • joint pain
  • muscle aching or cramping

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Signs of high or low blood pressure like very bad headache or dizziness, passing out, change in eyesight.
  • Weakness on 1 side of the body, trouble speaking or thinking, change in balance, drooping on one side of the face, or blurred eyesight.
  • Chest pain or pressure.
  • Fast or slow heartbeat.
  • A heartbeat that does not feel normal.
  • Shortness of breath.
  • Seizures.

How do I store and/or throw out Lexiscan?

  • If you need to store Lexiscan at home, talk with your doctor, nurse, or pharmacist about how to store it.

Consumer Information Use and Disclaimer

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else's drugs.
  • Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
  • Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Check with your pharmacist about how to throw out unused drugs.
  • Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about this medicine, please talk with your doctor, nurse, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

This information should not be used to decide whether or not to take Lexiscan (regadenoson) or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to Lexiscan. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Review Date: October 4, 2017

Indications and Usage for Lexiscan

Lexiscan (regadenoson) injection is a pharmacologic stress agent indicated for radionuclide myocardial perfusion imaging (MPI) in patients unable to undergo adequate exercise stress.

Contraindications

Do not administer Lexiscan to patients with:

• Second- or third-degree AV block, or • sinus node dysfunction

unless these patients have a functioning artificial pacemaker [see Warnings and Precautions (5.2)].

Adverse Reactions

The following adverse reactions are discussed in more detail in other sections of the labeling.

• Myocardial Ischemia [see Warnings and Precautions (5.1)] • Sinoatrial and Atrioventricular Nodal Block [see Warnings and Precautions (5.2)] • Atrial Fibrillation/Atrial Flutter [see Warnings and Precautions (5.3)] • Hypersensitivity, Including Anaphylaxis [see Warnings and Precautions (5.4)] • Hypotension [see Warnings and Precautions (5.5)] • Hypertension [see Warnings and Precautions (5.6)] • Bronchoconstriction [see Warnings and Precautions (5.7)] • Seizure [see Warnings and Precautions (5.8)] • Cerebrovascular Accident (Stroke) [see Warnings and Precautions (5.9)]

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

During clinical development, 1,651 patients were exposed to Lexiscan, with most receiving 0.4 mg as a rapid (≤ 10 seconds) intravenous injection. Most of these patients received Lexiscan in two clinical studies that enrolled patients who had no history of bronchospastic lung disease as well as no history of a cardiac conduction block of greater than first-degree AV block, except for patients with functioning artificial pacemakers. In these studies (Studies 1 and 2), 2,015 patients underwent myocardial perfusion imaging after administration of Lexiscan (N = 1,337) or ADENOSCAN (N = 678). The population was 26–93 years of age (median 66 years), 70% male and primarily Caucasian (76% Caucasian, 7% African American, 9% Hispanic, 5% Asian). Table 1 shows the most frequently reported adverse reactions.

Overall, any adverse reaction occurred at similar rates between the study groups (80% for the Lexiscan group and 83% for the ADENOSCAN group). Aminophylline was used to treat the reactions in 3% of patients in the Lexiscan group and 2% of patients in the ADENOSCAN group. Most adverse reactions began soon after dosing, and generally resolved within approximately 15 minutes, except for headache which resolved in most patients within 30 minutes.

Table 1 Adverse Reactions in Studies 1 and 2 Pooled (Frequency ≥ 5%)

Lexiscan
N = 1,337

ADENOSCAN
N = 678

Dyspnea

28%

26%

Headache

26%

17%

Flushing

16%

25%

Chest Discomfort

13%

18%

Angina Pectoris or ST Segment Depression

12%

18%

Dizziness

8%

7%

Chest Pain

7%

10%

Nausea

6%

6%

Abdominal Discomfort

5%

2%

Dysgeusia

5%

7%

Feeling Hot

5%

8%

ECG Abnormalities

The frequency of rhythm or conduction abnormalities following Lexiscan or ADENOSCAN is shown in Table 2 [see Warnings and Precautions (5.2)].

Table 2 Rhythm or Conduction Abnormalities* in Studies 1 and 2
* 12-lead ECGs were recorded before and for up to 2 hours after dosing. † includes rhythm abnormalities (PACs, PVCs, atrial fibrillation/flutter, wandering atrial pacemaker, supraventricular or ventricular arrhythmia) or conduction abnormalities, including AV block.

Lexiscan
N / N evaluable (%)

ADENOSCAN
N / N evaluable (%)

Rhythm or conduction abnormalities†

332/1275 (26%)

192/645 (30%)

Rhythm abnormalities

260/1275 (20%)

131/645 (20%)

PACs

86/1274 (7%)

57/645 (9%)

PVCs

179/1274 (14%)

79/645 (12%)

First-degree AV block (PR prolongation > 220 msec)

34/1209 (3%)

43/618 (7%)

Second-degree AV block

1/1209 (0.1%)

9/618 (1%)

AV conduction abnormalities (other than AV blocks)

1/1209 (0.1%)

0/618 (0%)

Ventricular conduction abnormalities

64/1152 (6%)

31/581 (5%)

Respiratory Abnormalities

In a randomized, placebo-controlled trial of 999 patients with asthma (n = 532) or stable chronic obstructive pulmonary disease (n = 467), the overall incidence of pre-specified respiratory adverse reactions was greater in the Lexiscan group compared to the placebo group (p < 0.001). Most respiratory adverse reactions resolved without therapy; a few patients received aminophylline or a short-acting bronchodilator. No differences were observed between treatment arms in the reduction of >15% from baseline at two-hours in FEV1 (Table 3).

Table 3 Respiratory Adverse Effects*
* All patients continued the use of their respiratory medications as prescribed prior to administration of Lexiscan. † Patients may have reported more than one type of adverse reaction. Adverse reactions were collected up to 24 hours following drug administration. Pre-specified respiratory adverse reactions included dyspnea, wheezing, obstructive airway disorder, dyspnea exertional, and tachypnea. ‡ Change from baseline at 2 hours.

Asthma Cohort

Chronic Obstructive Pulmonary Disease (COPD) Cohort

Lexiscan

(N=356)

Placebo

(N=176)

Lexiscan

(N=316)

Placebo

(N=151)

Overall Pre-specified Respiratory Adverse Reaction†

12.9%

2.3%

19.0%

4.0%

    Dyspnea

10.7%

1.1%

18.0%

2.6%

    Wheezing

3.1%

1.1%

0.9%

0.7%

FEV1 reduction >15%‡

1.1%

2.9%

4.2%

5.4%

Renal Impairment

In a randomized, placebo-controlled trial of 504 patients (Lexiscan n=334 and placebo n=170) with a diagnosis or risk factors for coronary artery disease and NKFK/DOQI Stage III or IV renal impairment (defined as GFR 15-59 mL/min/1.73 m2), no serious adverse events were reported through the 24-hour follow-up period.

Inadequate Exercise Stress

In an open-label, multi-center trial evaluating Lexiscan administration following inadequate exercise stress, 1,147 patients were randomized into one of two groups. Each group underwent two Lexiscan stress myocardial perfusion imaging (MPI) procedures. Group 1 received Lexiscan 3 minutes following inadequate exercise in the first Lexiscan stress (MPI 1). Group 2 rested 1 hour after inadequate exercise to allow hemodynamics to return to baseline prior to receiving Lexiscan (MPI 1). Both groups returned for a second stress MPI 1-14 days later and received Lexiscan without exercise (MPI 2).

The most common adverse reactions are similar in type and incidence to those in Table 1 above for both Groups. The timing of the administration of Lexiscan did not alter the common adverse reaction profile.

Table 4 shows a comparison of cardiac events of interest for the two groups [see Warnings and Precautions (5.1)]. The cardiac events were numerically higher in Group 1.

Table 4 Cardiac Events of Interest in Inadequate Exercise Stress Study
* A clinically significant cardiac event was defined as any of the following events found on the Holter ECG/12-lead ECG within one hour after regadenoson administration: ventricular arrhythmias (sustained ventricular tachycardia, ventricular fibrillation, Torsade de Pointes, ventricular flutter); ST-T depression (≥ 2 mm); ST-T elevation (≥ 1 mm); AV block (2:1 AV block, AV Mobitz I, AV Mobitz II, complete heart block); sinus arrest > 3 seconds in duration
Or
       •      a Treatment Emergent Adverse Event (TEAE) per the MedDRA SMQ (narrow Scope) for myocardial infarction
Or
       •      a TEAE preferred term (PT) of angina unstable within 24 hours of regadenoson administration.

Cardiac Event*

Group 1 / MPI 1

Lexiscan 3 minutes following exercise

(N=575)

Group 2 / MPI 1

Lexiscan 1 hour following exercise

(N=567)

17 (3.0%)

3 (0.5%)

Holter/12-Lead ECG Abnormality

   ST-T Depression (> 2 mm)

13 (2.3%)

2 (0.4%)

   ST-T Elevation (> 1 mm)

3 (0.5%)

1 (0.2%)

Acute coronary syndrome

1 (0.2%)

0

Myocardial infarction

1 (0.2%)

0

Post-Marketing Experience

The following adverse reactions have been reported from worldwide marketing experience with regadenoson. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Cardiovascular

Myocardial infarction, cardiac arrest, ventricular arrhythmias, supraventricular tachyarrhythmias including atrial fibrillation with rapid ventricular response (new-onset or recurrent), atrial flutter, heart block (including third-degree block), asystole, marked hypertension, symptomatic hypotension in association with transient ischemic attack, acute coronary syndrome (ACS), seizures and syncope [see Warnings and Precautions (5.1), (5.2), (5.3), (5.5), (5.6) and (5.8)] have been reported. Some events required intervention with fluids and/or aminophylline [see Overdosage (10)]. QTc prolongation shortly after Lexiscan administration has been reported.

Central Nervous System

Tremor, seizure, transient ischemic attack, and cerebrovascular accident including intracranial hemorrhage [see Warnings and Precautions (5.8) and (5.9)].

Gastrointestinal

Abdominal pain, occasionally severe, has been reported a few minutes after Lexiscan administration, in association with nausea, vomiting, or myalgias; administration of aminophylline, an adenosine antagonist, appeared to lessen the pain. Diarrhea and fecal incontinence have also been reported following Lexiscan administration.

Hypersensitivity

Anaphylaxis, angioedema, cardiac or respiratory arrest, respiratory distress, decreased oxygen saturation, hypotension, throat tightness, urticaria, rashes have occurred and have required treatment including resuscitation [see Warnings and Precautions (5.4)].

Musculoskeletal

Musculoskeletal pain has occurred, typically 10-20 minutes after Lexiscan administration; the pain was occasionally severe, localized in the arms and lower back and extended to the buttocks and lower legs bilaterally. Administration of aminophylline appeared to lessen the pain.

Respiratory

Respiratory arrest, dyspnea and wheezing have been reported following Lexiscan administration.

Overdosage

Lexiscan overdosage may result in serious reactions [see Warnings and Precautions (5)]. In a study of healthy volunteers, symptoms of flushing, dizziness and increased heart rate were assessed as intolerable at Lexiscan doses greater than 0.02 mg/kg.

Aminophylline to Reverse Effects

Methylxanthines, such as caffeine, aminophylline, and theophylline, are competitive adenosine receptor antagonists and aminophylline has been used to terminate persistent pharmacodynamic effects. Aminophylline may be administered in doses ranging from 50 mg to 250 mg by slow intravenous injection (50 mg to 100 mg over 30–60 seconds). Methylxanthine use is not recommended in patients who experience a seizure in association with Lexiscan administration [see Warnings and Precautions (5.8)].

Lexiscan Description

Regadenoson is an A2A adenosine receptor agonist that is a coronary vasodilator [see Clinical Pharmacology (12.1)]. Regadenoson is chemically described as adenosine, 2-[4-[(methylamino)carbonyl]-1H-pyrazol-1-yl]-, monohydrate. Its structural formula is:

The molecular formula for regadenoson is C15H18N8O5 • H2O and its molecular weight is 408.37.

Lexiscan is a sterile, nonpyrogenic solution for intravenous injection. The solution is clear and colorless. Each 1 mL in the 5 mL pre-filled syringe contains 0.084 mg of regadenoson monohydrate, corresponding to 0.08 mg regadenoson on an anhydrous basis, 10.9 mg dibasic sodium phosphate dihydrate or 8.7 mg dibasic sodium phosphate anhydrous, 5.4 mg monobasic sodium phosphate monohydrate, 150 mg propylene glycol, 1 mg edetate disodium dihydrate, and Water for Injection, with pH between 6.3 and 7.7.

Lexiscan - Clinical Pharmacology

Mechanism of Action

Regadenoson is a low affinity agonist (Ki ≈ 1.3 µM) for the A2A adenosine receptor, with at least 10-fold lower affinity for the A1 adenosine receptor (Ki > 16.5 µM), and weak, if any, affinity for the A2B and A3 adenosine receptors. Activation of the A2A adenosine receptor by regadenoson produces coronary vasodilation and increases coronary blood flow (CBF).

Pharmacodynamics

Coronary Blood Flow

Lexiscan causes a rapid increase in CBF which is sustained for a short duration. In patients undergoing coronary catheterization, pulsed-wave Doppler ultrasonography was used to measure the average peak velocity (APV) of coronary blood flow before and up to 30 minutes after administration of regadenoson (0.4 mg, intravenously). Mean APV increased to greater than twice baseline by 30 seconds and decreased to less than twice the baseline level within 10 minutes [see Clinical Pharmacology (12.3)].

Myocardial uptake of the radiopharmaceutical is proportional to CBF. Because Lexiscan increases blood flow in normal coronary arteries with little or no increase in stenotic arteries, Lexiscan causes relatively less uptake of the radiopharmaceutical in vascular territories supplied by stenotic arteries. MPI intensity after Lexiscan administration is therefore greater in areas perfused by normal relative to stenosed arteries.

Effect of Aminophylline

Aminophylline (100 mg, administered by slow intravenous injection over 60 seconds) injected 1 minute after 0.4 mg Lexiscan in patients undergoing cardiac catheterization, was shown to shorten the duration of the coronary blood flow response to Lexiscan as measured by pulsed-wave Doppler ultrasonography [see Overdosage (10)].

Effect of Caffeine

Ingestion of caffeine decreases the ability to detect reversible ischemic defects. In a placebo-controlled, parallel group clinical study, patients with known or suspected myocardial ischemia received a baseline rest/stress MPI followed by a second stress MPI. Patients received caffeine or placebo 90 minutes before the second Lexiscan stress MPI. Following caffeine administration (200 or 400 mg), the mean number of reversible defects identified was reduced by approximately 60%. This decrease was statistically significant [see Drug Interactions (7.1) and Patient Counseling Information (17)].

Hemodynamic Effects

In clinical studies, the majority of patients had an increase in heart rate and a decrease in blood pressure within 45 minutes after administration of Lexiscan. Maximum hemodynamic changes after Lexiscan and ADENOSCAN in Studies 1 and 2 are summarized in Table 5.

Table 5 Hemodynamic Effects in Studies 1 and 2
Vital Sign Parameter Lexiscan
N = 1,337
ADENOSCAN
N = 678

Heart Rate

> 100 bpm

22%

13%

Increase > 40 bpm

5%

3%

Systolic Blood Pressure

< 90 mm Hg

2%

3%

Decrease > 35 mm Hg

7%

8%

≥ 200 mm Hg

1.9%

1.9%

Increase ≥ 50 mm Hg

0.7%

0.8%

≥ 180 mm Hg and increase of
≥ 20 mm Hg from baseline

4.6%

3.2%

Diastolic Blood Pressure

< 50 mm Hg

2%

4%

Decrease > 25 mm Hg

4%

5%

≥ 115 mm Hg

0.9%

0.9%

Increase ≥ 30 mm Hg

0.5%

1.1%

Hemodynamic Effects Following Inadequate Exercise

In a clinical study, Lexiscan was administered for MPI following inadequate exercise stress. More patients with Lexiscan administration three minutes following inadequate exercise stress had an increase in heart rate and a decrease in systolic blood pressure compared with Lexiscan administered at rest. The changes were not associated with any clinically significant adverse reactions. Maximum hemodynamic changes are presented in Table 6.

Table 6 Hemodynamic Effects in Inadequate Exercise Stress Study

Vital Sign Parameter

Group 1 / MPI 1

Lexiscan 3 minutes

following exercise

(N=575)

Group 2 / MPI 1

Lexiscan 1 hour

following exercise

(N=567)

Heart Rate

> 100 bpm

44%

31%

Increase > 40 bpm

5%

16%

Systolic Blood Pressure

< 90 mm Hg

2%

4%

Decrease > 35 mm Hg

29%

10%

≥ 200 mm Hg

0.9%

0.4%

Increase ≥ 50 mm Hg

2%

0.4%

≥ 180 mm Hg and increase of
≥ 20 mm Hg from baseline

5%

2%

Diastolic Blood Pressure

< 50 mm Hg

3%

3%

Decrease > 25 mm Hg

6%

5%

≥ 115 mm Hg

0.7%

0.4%

Increase ≥ 30 mm Hg

2%

1%

Respiratory Effects

The A2B and A3 adenosine receptors have been implicated in the pathophysiology of bronchoconstriction in susceptible individuals (i.e., asthmatics). In in vitro studies, regadenoson has not been shown to have appreciable binding affinity for the A2B and A3 adenosine receptors.

In a randomized, placebo-controlled clinical trial of 999 patients with a diagnosis, or risk factors for, coronary artery disease and concurrent asthma or COPD, the incidence of respiratory adverse reactions (dyspnea, wheezing) was greater with Lexiscan compared to placebo. Moderate (2.5%) or severe (< 1%) respiratory reactions were observed more frequently in the Lexiscan group compared to placebo [see Adverse Reactions (6.1)].

Pharmacokinetics

In healthy subjects, the regadenoson plasma concentration-time profile is multi-exponential in nature and best characterized by 3-compartment model. The maximal plasma concentration of regadenoson is achieved within 1 to 4 minutes after injection of Lexiscan and parallels the onset of the pharmacodynamic response. The half-life of this initial phase is approximately 2 to 4 minutes. An intermediate phase follows, with a half-life on average of 30 minutes coinciding with loss of the pharmacodynamic effect. The terminal phase consists of a decline in plasma concentration with a half-life of approximately 2 hours [see Clinical Pharmacology (12.2)]. Within the dose range of 0.3–20 µg/kg in healthy subjects, clearance, terminal half-life or volume of distribution do not appear dependent upon the dose.

A population pharmacokinetic analysis including data from subjects and patients demonstrated that regadenoson clearance decreases in parallel with a reduction in creatinine clearance and clearance increases with increased body weight. Age, gender, and race have minimal effects on the pharmacokinetics of regadenoson.

Specific Populations

Renally Impaired Patients: The disposition of regadenoson was studied in 18 patients with various degrees of renal function and in 6 healthy subjects. With increasing renal impairment, from mild (CLcr 50 to < 80 mL/min) to moderate (CLcr 30 to < 50 mL/min) to severe renal impairment (CLcr < 30 mL/min), the fraction of regadenoson excreted unchanged in urine and the renal clearance decreased, resulting in increased elimination half-lives and AUC values compared to healthy subjects (CLcr ≥ 80 mL/min). However, the maximum observed plasma concentrations as well as volumes of distribution estimates were similar across the groups. The plasma concentration-time profiles were not significantly altered in the early stages after dosing when most pharmacologic effects are observed. No dose adjustment is needed in patients with renal impairment.

Patients with End Stage Renal Disease: The pharmacokinetics of regadenoson in patients on dialysis has not been assessed; however, in an in vitro study regadenoson was found to be dialyzable.

Hepatically Impaired Patients: The influence of hepatic impairment on the pharmacokinetics of regadenoson has not been evaluated. Because greater than 55% of the dose is excreted in the urine as unchanged drug and factors that decrease clearance do not affect the plasma concentration in the early stages after dosing when clinically meaningful pharmacologic effects are observed, no dose adjustment is needed in patients with hepatic impairment.

Geriatric Patients: Based on a population pharmacokinetic analysis, age has a minor influence on the pharmacokinetics of regadenoson. No dose adjustment is needed in elderly patients.

Metabolism

The metabolism of regadenoson is unknown in humans. Incubation with rat, dog, and human liver microsomes as well as human hepatocytes produced no detectable metabolites of regadenoson.

Excretion

In healthy volunteers, 57% of the regadenoson dose is excreted unchanged in the urine (range 19-77%), with an average plasma renal clearance around 450 mL/min, i.e., in excess of the glomerular filtration rate. This indicates that renal tubular secretion plays a role in regadenoson elimination.

Clinical Studies

Agreement between Lexiscan and ADENOSCAN

The efficacy and safety of Lexiscan were determined relative to ADENOSCAN in two randomized, double-blind studies (Studies 1 and 2) in 2,015 patients with known or suspected coronary artery disease who were indicated for pharmacologic stress MPI. A total of 1,871 of these patients had images considered valid for the primary efficacy evaluation, including 1,294 (69%) men and 577 (31%) women with a median age of 66 years (range 26–93 years of age). Each patient received an initial stress scan using ADENOSCAN (6-minute infusion using a dose of 0.14 mg/kg/min, without exercise) with a radionuclide gated SPECT imaging protocol. After the initial scan, patients were randomized to either Lexiscan or ADENOSCAN, and received a second stress scan with the same radionuclide imaging protocol as that used for the initial scan. The median time between scans was 7 days (range of 1–104 days).

The most common cardiovascular histories included hypertension (81%), CABG, PTCA or stenting (51%), angina (63%), and history of myocardial infarction (41%) or arrhythmia (33%); other medical history included diabetes (32%) and COPD (5%). Patients with a recent history of serious uncontrolled ventricular arrhythmia, myocardial infarction, or unstable angina, a history of greater than first-degree AV block, or with symptomatic bradycardia, sick sinus syndrome, or a heart transplant were excluded. A number of patients took cardioactive medications on the day of the scan, including β-blockers (18%), calcium channel blockers (9%), and nitrates (6%). In the pooled study population, 68% of patients had 0–1 segments showing reversible defects on the initial scan, 24% had 2–4 segments, and 9% had ≥ 5 segments.

Comparison of the images obtained with Lexiscan to those obtained with ADENOSCAN was performed as follows. Using the 17-segment model, the number of segments showing a reversible perfusion defect was calculated for the initial ADENOSCAN study and for the randomized study obtained using Lexiscan or ADENOSCAN. The agreement rate for the image obtained with Lexiscan or ADENOSCAN relative to the initial ADENOSCAN image was calculated by determining how frequently the patients assigned to each initial ADENOSCAN category (0–1, 2–4, 5–17 reversible segments) were placed in the same category with the randomized scan. The agreement rates for Lexiscan and ADENOSCAN were calculated as the average of the agreement rates across the three categories determined by the initial scan. Studies 1 and 2 each demonstrated that Lexiscan is similar to ADENOSCAN in assessing the extent of reversible perfusion abnormalities (Table 7).

Table 7 Agreement Rates in Studies 1 and 2
Study 1 Study 2

ADENOSCAN  – ADENOSCAN Agreement Rate (± SE)

61 ± 3%

64 ± 4%

ADENOSCAN  – Lexiscan Agreement Rate (± SE)

62 ± 2%

63 ± 3%

Rate Difference (Lexiscan  – ADENOSCAN) (± SE)

1 ± 4%

-1 ± 5%

95% Confidence Interval

-7.5, 9.2%

-11.2, 8.7%

Use of Lexiscan in Patients with Inadequate Exercise Stress

The efficacy and safety of Lexiscan administered 3 minutes (Group 1) or 1 hour (Group 2) following inadequate exercise stress were evaluated in an open-label randomized, multi-center, non-inferiority study. Adequate exercise was defined as ≥ 85% maximum predicted heart rate and ≥ 5 METS. SPECT MPI was performed 60-90 minutes after Lexiscan administration in each group (MPI 1). Patients returned 1-14 days later to undergo a second stress MPI with Lexiscan without exercise (MPI 2).

All patients were referred for evaluation of coronary artery disease. Of the 1,147 patients randomized, a total of 1,073 patients received Lexiscan and had interpretable SPECT scans at all visits; 538 in Group 1 and 535 in Group 2. The median age of the patients was 62 years (range 28 to 90 years) and included 633 (59%) men and 440 (41%) women.

Images from MPI 1 and MPI 2 for the two groups were compared for presence or absence of perfusion defects. The level of agreement between the MPI 1 and the MPI 2 reads in Group 1 was similar to the level of agreement between MPI 1 and MPI 2 reads in Group 2. However, two patients receiving Lexiscan 3 minutes following inadequate exercise experienced a serious cardiac adverse reaction. No serious cardiac adverse reactions occurred in patients receiving Lexiscan 1 hour following inadequate exercise stress [see Adverse Reactions (6.1) Clinical Pharmacology (12.2)].

How is Lexiscan given?

Lexiscan is injected into a vein through an IV. A healthcare provider will give you this injection.

After Lexiscan is injected, you will be given other intravenous (IV) medications that allow blood vessels to be seen more clearly on the radiologic examination.

Your breathing, blood pressure, oxygen levels, and other vital signs will be watched closely during your stress test.

For Healthcare Professionals

Applies to regadenoson: intravenous solution

General

The most common adverse reactions were dyspnea, headache, rhythm or conduction abnormalities, flushing, and rhythm abnormalities.[Ref]

Cardiovascular

Very common (10% or more): Rhythm or conduction abnormalities (26%), flushing (up to 23%), rhythm abnormalities (20%), ECG ST segment changes (18%), premature ventricular contractions (14%), angina pectoris or ST segment depression (12%)
Common (1% to 10%): Premature atrial contractions, first degree atrioventricular (AV) block (PR prolongation greater than 220 msec), ventricular conduction abnormalities, decreased systolic blood pressure (greater than 35 mmHg), decreased diastolic blood pressure (greater than 25 mmHg), angina pectoris, AV block, tachycardia, palpitations, other ECG abnormalities including QTc prolongation, hypotension, ST to T depression of 2 mm or more
Uncommon (0.1% to 1%): Second degree AV block, AV conduction abnormalities other than AV block, cardiac arrest, myocardial infarction, complete AV block, bradycardia, atrial flutter, atrial fibrillation (new-onset, worsening, or recurrent), hypertension, pallor, peripheral coldness, increased systolic blood pressure (50 mmHg or more), increased diastolic blood pressure (30 mmHg or more), ST to T elevation of 1 mm or more, acute coronary syndrome
Postmarketing reports: Ventricular arrhythmias, supraventricular tachyarrhythmias, asystole, marked hypertension, symptomatic hypotension[Ref]

Respiratory

Pre-specified respiratory adverse reactions included dyspnea, wheezing, obstructive airway disorder, dyspnea exertional, and tachypnea.[Ref]

Very common (10% or more): Dyspnea (up to 29%), pre-specified respiratory adverse reaction (up to 19%)
Common (1% to 10%): Wheezing, throat tightness, throat irritation, cough
Uncommon (0.1% to 1%): Tachypnea
Postmarketing reports: Respiratory arrest, respiratory distress, oxygen saturation decreased[Ref]

Nervous system

Very common (10% or more): Headache (27%), dizziness (up to 11%)
Common (1% to 10%): Dysgeusia, paresthesia, hypoesthesia, severe headache
Uncommon (0.1% to 1%): Convulsions, syncope, transient ischemic attack, unresponsiveness to stimuli, depressed level of consciousness, tremor, somnolence, tinnitus
Rare (less than 0.1%): Cerebrovascular accident
Postmarketing reports: Intracranial hemorrhage[Ref]

Other

Very common (10% or more): Chest pain (up to 19%), chest discomfort (13%)
Common (1% to 10%): Malaise, asthenia
Uncommon (0.1% to 1%): General body pain[Ref]

Gastrointestinal

Very common (10% or more): Gastrointestinal discomfort (15%)
Common (1% to 10%): Nausea, abdominal discomfort, vomiting, oral discomfort
Uncommon (0.1% to 1%): Abdominal distention, diarrhea, fecal incontinence
Postmarketing reports: Abdominal pain[Ref]

Musculoskeletal

Common (1% to 10%): Back or neck or jaw pain, pain in extremity, musculoskeletal discomfort
Uncommon (0.1% to 1%): Arthralgia[Ref]

Dermatologic

Common (1% to 10%): Hyperhidrosis
Uncommon (0.1% to 1%): Angioedema, urticaria, rash, erythema[Ref]

Ocular

Uncommon (0.1% to 1%): Vision blurred, eye pain[Ref]

Psychiatric

Uncommon (0.1% to 1%): Anxiety, insomnia[Ref]

Immunologic

Uncommon (0.1% to 1%): Anaphylaxis[Ref]

Local

Uncommon (0.1% to 1%): Pain at injection site[Ref]

Some side effects of Lexiscan may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

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