1.1 Magnetic Resonance Imaging (MRI) of the Central Nervous System (CNS)

Gadobutrol injection is indicated for use with magnetic resonance imaging (MRI) in adult and pediatric patients, including term neonates to detect and visualize areas with disrupted blood brain barrier and/or abnormal vascularity of the central nervous system.

1.2 MRI of the Breast

Gadobutrol injection is indicated for use with MRI in adult patients to assess the presence and extent of malignant breast disease.

1.3 Magnetic Resonance Angiography (MRA)

Gadobutrol injection is indicated for use in magnetic resonance angiography (MRA) in adult and pediatric patients, including term neonates, to evaluate known or suspected supra-aortic or renal artery disease.

1.4 Cardiac MRI

Gadobutrol injection is indicated for use in cardiac MRI (CMRI) to assess myocardial perfusion (stress, rest) and late gadolinium enhancement in adult patients with known or suspected coronary artery disease (CAD).

2.1 Recommended Dose

The recommended dose of gadobutrol injection for adult and pediatric patients (including term neonates) is 0.1 mL/kg body weight (0.1 mmol/kg). Refer to Table 1 to determine the volume to be administered.

*for Cardiac MRI, the dose is divided into 2 separate, equal injections

2.2 Administration Guidelines

• Gadobutrol injection is formulated at a higher concentration (1 mmol/mL) compared to certain other gadolinium based contrast agents, resulting in a lower volume of administration. Use Table 1 to determine the volume to be administered.
• Use sterile technique when preparing and administering gadobutrol injection.

2.3 Drug Handling

• Visually inspect gadobutrol injection for particulate matter and discoloration prior to administration. Do not use the solution if it is discolored, if particulate matter is present or if the container appears damaged.
• Do not mix gadobutrol injection with other medications and do not administer gadobutrol injection in the same intravenous line simultaneously with other medications because of the potential for chemical incompatibility.

5.1 Nephrogenic Systemic Fibrosis

Gadolinium-based contrast agents (GBCAs) increase the risk for nephrogenic systemic fibrosis (NSF) among patients with impaired elimination of the drugs. Avoid use of GBCAs among these patients unless the diagnostic information is essential and not available with non-contrast MRI or other modalities. The GBCA-associated NSF risk appears highest for patients with chronic, severe kidney disease (GFR < 30 mL/min/1.73m2) as well as patients with acute kidney injury. The risk appears lower for patients with chronic, moderate kidney disease (GFR 30 to 59 mL/min/1.73m2) and little, if any, for patients with chronic, mild kidney disease (GFR 60 to 89 mL/min/1.73m2). NSF may result in fatal or debilitating fibrosis affecting the skin, muscle and internal organs. Report any diagnosis of NSF following gadobutrol injection administration to Fresenius Kabi USA, LLC at 1-800-551-7176 or FDA (1-800-FDA-1088 or www.fda.gov/medwatch).

Screen patients for acute kidney injury and other conditions that may reduce renal function. Features of acute kidney injury consist of rapid (over hours to days) and usually reversible decrease in kidney function, commonly in the setting of surgery, severe infection, injury or drug-induced kidney toxicity. Serum creatinine levels and estimated GFR may not reliably assess renal function in the setting of acute kidney injury. For patients at risk for chronically reduced renal function (for example, age > 60 years, diabetes mellitus or chronic hypertension), estimate the GFR through laboratory testing.

Among the factors that may increase the risk for NSF are repeated or higher than recommended doses of a GBCA and degree of renal impairment at the time of exposure. Record the specific GBCA and the dose administered to a patient. For patients at highest risk for NSF, do not exceed the recommended gadobutrol injection dose and allow a sufficient period of time for elimination of the drug prior to re-administration. For patients receiving hemodialysis, consider the prompt initiation of hemodialysis following the administration of a GBCA in order to enhance the contrast agent’s elimination [see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3)]. The usefulness of hemodialysis in the prevention of NSF is unknown [see Clinical Pharmacology (12.3)].

5.2 Hypersensitivity Reactions

Anaphylactic and other hypersensitivity reactions with cardiovascular, respiratory or cutaneous manifestations, ranging from mild to severe, including death, have uncommonly occurred following gadobutrol injection administration [see Adverse Reactions (6)].

• Before gadobutrol injection administration, assess all patients for any history of a reaction to contrast media, bronchial asthma and/or allergic disorders. These patients may have an increased risk for a hypersensitivity reaction to gadobutrol injection.
• Administer gadobutrol injection only in situations where trained personnel and therapies are promptly available for the treatment of hypersensitivity reactions, including personnel trained in resuscitation.

Most hypersensitivity reactions to gadobutrol injection have occurred within half an hour after administration. Delayed reactions can occur up to several days after administration. Observe patients for signs and symptoms of hypersensitivity reactions during and following gadobutrol injection administration.

5.3 Gadolinium Retention

Gadolinium is retained for months or years in several organs. The highest concentrations (nanomoles per gram of tissue) have been identified in the bone, followed by other organs (for example, brain, skin, kidney, liver, and spleen). The duration of retention also varies by tissue and is longest in bone. Linear GBCAs cause more retention than macrocyclic GBCAs. At equivalent doses, gadolinium retention varies among the linear agents with Omniscan (gadodiamide) and Optimark (gadoversetamide) causing greater retention than other linear agents [Eovist (gadoxetate disodium), Magnevist (gadopentetate dimeglumine), MultiHance (gadobenate dimeglumine)]. Retention is lowest and similar among the macrocyclic GBCAs [Dotarem (gadoterate meglumine), Gadobutrol injection (gadobutrol), ProHance (gadoteridol)].

Consequences of gadolinium retention in the brain have not been established. Pathologic and clinical consequences of GBCA administration and retention in skin and other organs have been established in patients with impaired renal function [see Warnings and Precautions (5.1)]. There are rare reports of pathologic skin changes in patients with normal renal function. Adverse events involving multiple organ systems have been reported in patients with normal renal function without an established causal link to gadolinium retention [see Adverse Reactions (6.2)].

While clinical consequences of gadolinium retention have not been established in patients with normal renal function, certain patients might be at higher risk. These include patients requiring multiple lifetime doses, pregnant and pediatric patients, and patients with inflammatory conditions. Consider the retention characteristics of the agent when choosing a GBCA for these patients. Minimize repetitive GBCA imaging studies particularly closely spaced studies, when possible.

5.4 Acute Kidney Injury

In patients with chronic renal impairment, acute kidney injury sometimes requiring dialysis has been observed with the use of some GBCAs. Do not exceed the recommended dose; the risk of acute kidney injury may increase with higher than recommended doses.

5.5 Extravasation and Injection Site Reactions

Ensure catheter and venous patency before the injection of gadobutrol injection. Extravasation into tissues during gadobutrol injection administration may result in moderate irritation [see Nonclinical Toxicology (13.2)].

5.6 Overestimation of Extent of Malignant Disease in MRI of the Breast

Gadobutrol injection MRI of the breast overestimated the histologically confirmed extent of malignancy in the diseased breast in up to 50% of the patients [see Clinical Studies (14.2)].

5.7 Low Sensitivity for Significant Arterial Stenosis

The performance of gadobutrol injection MRA for detecting arterial segments with significant stenosis (>50% renal, >70% supra-aortic) has not been shown to exceed 55%. Therefore, a negative MRA study alone should not be used to rule out significant stenosis [see Clinical Studies (14.3)].

6.1 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 clinical practice.

The adverse reactions described in this section reflect gadobutrol injection exposure in 7,713 subjects (including 184 pediatric patients, ages 0 to 17 years) with the majority receiving the recommended dose. Approximately 52% of the subjects were male and the ethnic distribution was 62% Caucasian, 28% Asian, 5% Hispanic, 2.5% Black, and 2.5% patients of other ethnic groups. The average age was 56 years (range from 1 week to 93 years).

Overall, approximately 4% of subjects reported one or more adverse reactions during a follow-up period that ranged from 24 hours to 7 days after gadobutrol injection administration.

Adverse reactions associated with the use of gadobutrol injection were usually mild to moderate in severity and transient in nature.

Table 2 lists adverse reactions that occurred in ≥ 0.1% subjects who received gadobutrol injection.

Adverse reactions that occurred with a frequency of < 0.1% in subjects who received gadobutrol injection include: hypersensitivity/anaphylactic reaction, loss of consciousness, convulsion, parosmia, tachycardia, palpitation, dry mouth, malaise and feeling cold.

6.2 Postmarketing Experience

The following additional adverse reactions have been reported during postmarketing use of gadobutrol injection. Because these reactions are reported voluntarily from a population of uncertain size, it is not possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

• Cardiac arrest
• Nephrogenic Systemic Fibrosis (NSF)
• Hypersensitivity reactions (anaphylactic shock, circulatory collapse, respiratory arrest, pulmonary edema, bronchospasm, cyanosis, oropharyngeal swelling, laryngeal edema, blood pressure increased, chest pain, angioedema, conjunctivitis, hyperhidrosis, cough, sneezing, burning sensation, and pallor) [see Warnings and Precautions (5.2)].
• General Disorders and Administration Site Conditions: Adverse events with variable onset and duration have been reported after GBCA administration [see Warnings and Precautions (5.3)]. These include fatigue, asthenia, pain syndromes, and heterogeneous clusters of symptoms in the neurological, cutaneous, and musculoskeletal systems.
• Skin: Gadolinium associated plaques

8.1 Pregnancy

8.2 Lactation

8.4 Pediatric Use

The safety and effectiveness of gadobutrol injection have been established in pediatric patients, including term neonates, for use with MRI to detect and visualize areas with disrupted blood brain barrier and/or abnormal vascularity of the central nervous system and for use in MRA to evaluate known or suspected supra-aortic or renal artery disease. Use of gadobutrol injection in these indications is supported by adequate and well-controlled studies in adults and supportive imaging data in two studies in 135 patients 2 to less than 18 years of age and 44 patients less than 2 years of age with CNS and non-CNS lesions, and pharmacokinetic data in 130 patients 2 to less than 18 years of age and 43 patients less than 2 years of age, including term neonates [see Clinical Pharmacology (12.3), and Clinical Studies (14.1)]. The frequency, type, and severity of adverse reactions in pediatric patients were similar to adverse reactions in adults [see Adverse Reactions (6.1)]. No dose adjustment according to age is necessary in pediatric patients [see Dosage and Administration (2.1), Clinical Pharmacology (12.3), and Clinical Studies (14.1)]. The safety and effectiveness of gadobutrol injection have not been established in preterm neonates for any indication or in pediatric patients of any age for use with MRI to assess the presence and extent of malignant breast disease, or for use in CMRI to assess myocardial perfusion (stress, rest) and late gadolinium enhancement in patients with known or suspected coronary artery disease (CAD).

8.5 Geriatric Use

In clinical studies of gadobutrol injection, 1,377 patients were 65 years of age and over, while 104 patients  were 80 years of age and over. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, use of gadobutrol injection in elderly patients should be cautious, reflecting the greater frequency of impaired renal function and concomitant disease or other drug therapy. No dose adjustment according to age is necessary in this population.

8.6 Renal Impairment

Prior to administration of gadobutrol injection, screen all patients for renal dysfunction by obtaining a history and/or laboratory tests [see Warnings and Precautions (5.1)]. No dosage adjustment is recommended for patients with renal impairment.

Gadobutrol can be removed from the body by hemodialysis [see Warnings and Precautions (5.1) and Clinical Pharmacology (12.3)].

12.1 Mechanism of Action

In MRI, visualization of normal and pathological tissue depends in part on variations in the radiofrequency signal intensity that occurs with:

• Differences in proton density
• Differences of the spin-lattice or longitudinal relaxation times (T1)
• Differences in the spin-spin or transverse relaxation time (T2)

When placed in a magnetic field, gadobutrol shortens the T1 and T2 relaxation times. The extent of decrease of T1 and T2 relaxation times, and therefore the amount of signal enhancement obtained from gadobutrol, is based upon several factors including the concentration of gadobutrol in the tissue, the field strength of the MRI system, and the relative ratio of the longitudinal and transverse relaxation times. At the recommended dose, the T1 shortening effect is observed with greatest sensitivity in T1-weighted magnetic resonance sequences. In T2*-weighted sequences the induction of local magnetic field inhomogeneities by the large magnetic moment of gadolinium and at high concentrations (during bolus injection) leads to a signal decrease.

12.2 Pharmacodynamics

Gadobutrol leads to distinct shortening of the relaxation times even in low concentrations. At pH 7, 37°C and 1.5 T, the relaxivity (r1) - determined from the influence on the relaxation times (T1) of protons in plasma - is 5.2 L/(mmol·sec) and the relaxivity (r2) - determined from the influence on the relaxation times (T2) - is 6.1 L/(mmol·sec). These relaxivities display only slight dependence on the strength of the magnetic field. The T1 shortening effect of paramagnetic contrast agents is dependent on concentration and r1 relaxivity (see Table 3). This may improve tissue visualization.

Compared to 0.5 molar gadolinium-based contrast agents, the higher concentration of gadobutrol injection results in half the volume of administration and a more compact contrast bolus injection. At the site of imaging, the relative height and width of the time intensity curve for gadobutrol injection varies as a function of imaging location and multiple patient, injection, and device-specific factors.

Gadobutrol is a water-soluble, hydrophilic compound with a partition coefficient between n-butanol and buffer at pH 7.6 of about 0.006.

12.3 Pharmacokinetics

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

No carcinogenicity studies of gadobutrol have been conducted.

Gadobutrol was not mutagenic in in vitro reverse mutation tests in bacteria, in the HGPRT (hypoxanthine-guanine phosphoribosyl transferase) test using cultured Chinese hamster V79 cells, or in chromosome aberration tests in human peripheral blood lymphocytes, and was negative in an in vivo micronucleus test in mice after intravenous injection of 0.5 mmol/kg.

Gadobutrol had no effect on fertility and general reproductive performance of male and female rats when given in doses 12.2 times the human equivalent dose (based on body surface area).

13.2 Animal Toxicology and/or Pharmacology

Local intolerance reactions, including moderate irritation associated with infiltration of inflammatory cells was observed after paravenous administration to rabbits, suggesting the possibility of occurrence of local irritation if the contrast medium leaks around veins in a clinical setting [see Warnings and Precautions (5.5)].

14.1 MRI of the CNS

Patients referred for MRI of the central nervous system with contrast were enrolled in two clinical trials that evaluated the visualization characteristics of lesions. In both studies, patients underwent a baseline, pre-contrast MRI prior to administration of gadobutrol injection at a dose of 0.1 mmol/kg, followed by a post-contrast MRI. In Study A, patients also underwent an MRI before and after the administration of gadoteridol. The studies were designed to demonstrate superiority of gadobutrol injection MRI to non-contrast MRI for lesion visualization. For both studies, pre-contrast and pre-plus-post contrast images (paired images) were independently evaluated by three readers for contrast enhancement and border delineation using a scale of 1 to 4, and for internal morphology using a scale of 1 to 3 (Table 5). Lesion counting was also performed to demonstrate non-inferiority of paired gadobutrol injection image sets to pre-contrast MRI. Readers were blinded to clinical information.

Efficacy was determined in 657 subjects. The average age was 49 years (range 18 to 85 years) and 42% were male. The ethnic representations were 39% Caucasian, 4% Black, 16% Hispanic, 38% Asian, and 3% of other ethnic groups.

Table 6 shows a comparison of visualization results between paired images and pre-contrast images. Gadobutrol injection provided a statistically significant improvement for each of the three lesion visualization parameters when averaged across three independent readers for each study.

Performances of gadobutrol and gadoteridol for visualization parameters were similar. Regarding the number of lesions detected, Study B met the prespecified noninferiority margin of -0.35 for paired read versus pre-contrast read while in Study A, gadobutrol and gadoteridol did not.

For the visualization endpoints contrast enhancement, border delineation, and internal morphology, the percentage of patients scoring higher for paired images compared to pre-contrast images ranged from 93% to 99% for Study A, and 95% to 97% for Study B. For both studies, the mean number of lesions detected on paired images exceeded that of the pre-contrast images; 37% for Study A and 24% for Study B. There were 29% and 11% of subjects in which the pre-contrast images detected more lesions for Study A and Study B, respectively.

The percentage of patients whose average reader mean score changed by ≤ 0, up to 1, up to 2, and ≥ 2 scoring categories presented in Table 5 is shown in Table 7. The categorical improvement of (≤ 0) represents higher (< 0) or identical (= 0) scores for the pre-contrast read, the categories with scores > 0 represent the magnitude of improvement seen for the paired read.

For both studies, the improvement of visualization endpoints in paired gadobutrol injection images compared to pre-contrast images resulted in improved assessment of normal and abnormal CNS anatomy.

14.2 MRI of the Breast

Patients with recently diagnosed breast cancer were enrolled in two identical clinical trials to evaluate the ability of gadobutrol injection to assess the presence and extent of malignant breast disease prior to surgery. Patients underwent non-contrast breast MRI (BMR) prior to gadobutrol injection (0.1 mmol/kg) breast MRI. BMR images and gadobutrol injection BMR (combined contrast plus non-contrast) images were independently evaluated in each study by three readers blinded to clinical information. In separate reading sessions the BMR images and gadobutrol injection BMR images were also interpreted together with X-ray mammography images (XRM).

The studies evaluated 787 patients: Study 1 enrolled 390 women with an average age of 56 years, 74% were white, 25% Asian, 0.5% black, and 0.5% other; Study 2 enrolled 396 women and 1 man with an average age of 57 years, 71% were white, 24% Asian, 3% black, and 2% other.

The readers assessed 5 regions per breast for the presence of malignancy using each reading modality. The readings were compared to an independent standard of truth (SoT) consisting of histopathology for all regions where excisions were made and tissue evaluated. XRM plus ultrasound was used for all other regions.

The assessment of malignant disease was performed using a region based within-subject sensitivity. Sensitivity for each reading modality was defined as the mean of the percentage of malignant breast regions correctly interpreted for each subject. The within-subject sensitivity of gadobutrol injection BMR was superior to that of BMR. The lower bound of the 95% Confidence Interval (CI) for the difference in within-subject sensitivity ranged from 19% to 42% for Study 1 and from 12% to 27% for Study 2. The within-subject sensitivity for gadobutrol injection BMR and BMR as well as for gadobutrol injection BMR plus XRM and BMR plus XRM is presented in Table 8.

Specificity was defined as the percentage of non-malignant breasts correctly identified as non-malignant. The lower limit of the 95% confidence interval for specificity of gadobutrol injection BMR was greater than 80% for 5 of 6 readers. (Table 9)

Three additional readers in each study read XRM alone. For these readers over both studies, sensitivity ranged from 68% to 73% and specificity in non-malignant breasts ranged from 86% to 94%.

In breasts with malignancy, a false positive detection rate was calculated as the percentage of subjects for which the readers assessed a region as malignant which could not be verified by SoT. The false positive detection rates for gadobutrol injection BMR ranged from 39% to 53% (95% CI Upper Bounds ranged from 44% to 58%).

14.3 MRA

Patients with known or suspected disease of the supra-aortic arteries (for evaluation up to but excluding the basilar artery) were enrolled in Study C, and patients with known or suspected disease of the renal arteries were enrolled in Study D. In both studies, non-contrast, 2D time-of-flight (ToF) magnetic resonance angiography (MRA) was performed prior to gadobutrol injection MRA using a single intravenous injection of 0.1 mmol/kg. The injection rate of 1.5 mL/second was selected to extend the injection duration to at least half of the imaging duration. Imaging was performed with parallel-channel, 1.5T MRI devices and an automatic bolus tracking technique to trigger the image acquisition following gadobutrol injection administration using elliptically encoded, T1-weighted, 3D gradient-echo image acquisition and single breath hold. Three central readers blinded to clinical information interpreted the ToF and gadobutrol injection MRA images. Three additional central readers interpreted separately acquired computed tomographic angiography (CTA) images, which were used as the standard of reference (SoR) in each study.

The studies included 749 subjects: 457 were evaluated in Study C, with an average age of 68 (range 25 to 93); 64% were male; 80% white, 28% black, and 16% Asian. An additional 292 subjects were evaluated in Study D, with an average age of 55 (range 18 to 88); 54% were male; 68% white, 7% black, and 22% Asian.

Efficacy was evaluated based on anatomical visualization and performance for distinguishing between normal and abnormal anatomy. The visualization metric depended on whether readers selected, “Yes, it can be visualized along its entire length...” when responding to the question, “Is this segment assessable?” Twenty-one segments in Study C and six segments in Study D were presented per subject to each reader. The performance metrics, sensitivity and specificity, depended on digital caliper-based quantitation of arterial narrowing in visualized, non-occluded, abnormal-appearing segments. Significant stenosis was defined as at least 70% in Study C and 50% in Study D. Performance of gadobutrol injection MRA compared to ToF MRA was calculated using an imputation method for non-visualized segments by assigning them as a 50% match with SoR and a 50% mismatch. Performance of gadobutrol injection MRA compared to a pre-specified threshold of 50% was calculated after excluding non-visualized segments. Measurement variability and visualization of accessory renal arteries was also evaluated.

Results were analyzed for each of the three central readers.

GAD MRA = Post-contrast Gadobutrol Injection Magnetic Resonance Angiography, ToF = Non-contrast 2D-Time of Flight.

For all three supra-aortic artery readers in Study C, the lower bound of confidence for the sensitivity of gadobutrol injection MRA did not exceed 54%. For all three renal artery readers in Study D, the lower bound of confidence for the sensitivity of gadobutrol injection MRA did not exceed 46%.

14.4 Cardiac MRI

Two studies similar in design, Study E and Study F, evaluated the sensitivity and specificity of gadobutrol injection cardiac MRI (CMRI) for detection of coronary artery disease (CAD) in adult patients with known or suspected CAD. Patients were excluded from study if they had a history of coronary artery bypass grafting, or if it was known in advance that they were unable to hold their breath, or had atrial fibrillation or other arrhythmia likely to prevent electrocardiogram-gated CMRI. The studies were multi-center, open-label, and evaluated 764 subjects for efficacy: 376 in Study E, with an average age of 59 (range 20 to 84); 69% male; 74% white, 1% black, and 25% Asian; and 388 subjects in Study F, with an average age of 59 (range 23 to 82); 61% male; 67% white, 17% black, and 12% Asian.

All subjects underwent dynamic first-pass gadobutrol injection imaging during vasodilator stress, followed ~10 minutes later by dynamic first-pass gadobutrol injection imaging at rest, followed ~5 minutes later with imaging during a period of gradual gadobutrol injection washout from the myocardium (late gadolinium enhancement, LGE). Imaging was performed on 1.5 T or 3.0 T MRI devices equipped with multichannel surface coils to support accelerated acquisitions with parallel imaging, T1-weighted, 2D gradient-echo, dynamic acquisition of perfusion with at least 3 slices per heartbeat. Gadobutrol injection was administered intravenously at a rate of ~4 mL/second as two separate bolus injections (0.05 mmol/kg each), the first at peak pharmacologic stress (~3 minutes after start of ongoing adenosine infusion, or immediately after completion of regadenoson administration, at approved doses). No additional gadobutrol injection was administered for LGE imaging.

Images were read by three independent readers blinded to clinical information. Reader detection of CAD depended on visually detecting defective perfusion or scar on gadobutrol injection CMRI (stress, rest, LGE) imaging. Quantitative coronary angiography (QCA) was used to measure intraluminal narrowing and served as the standard of reference (SoR).

Computed tomographic angiography (CTA) was used as the SoR if disease could be unequivocally excluded, and no coronary angiography (CA) was available. The left ventricular myocardium was divided into six regions. Readers provided per-region (CMRI, CTA) and per-artery (QCA) interpretations for each subject. Subject-level endpoints reflected each subject's most abnormal localized finding.

The sensitivity results for gadobutrol injection CMRI to detect CAD defined as either maximum stenosis ≥50% or ≥70% by QCA are presented in Table 12. For each reader, sensitivity of gadobutrol injection CMRI larger than 60% can be concluded if the lower 95% confidence limit of the sensitivity estimate exceeds the pre-specified threshold of 60%.

* Stenosis determined by Quantitative Coronary Angiography (QCA)
** CMRI images were assessed by six independent blinded readers, three in each study.
*** The bolded value represents the lower limit of the 95% confidence interval, which is compared to a pre-specified threshold of 60% for evaluation of sensitivity.

The specificity results for gadobutrol injection CMRI to detect CAD defined as either maximum stenosis ≥50% or ≥70% by QCA are presented in Table 13. For each reader, specificity of gadobutrol injection CMRI larger than 55% can be concluded if the lower 95% confidence limit of the specificity estimate exceeds the pre-specified threshold of 55%.

* Stenosis determined by Quantitative Coronary Angiography (QCA)
** CMRI images were assessed by six independent blinded readers, three in each study.
*** The bolded value represents the lower limit of the 95% confidence interval, which is compared to a pre-specified threshold of 55% for evaluation of specificity.

In Study E, among the 33 patients with maximum stenosis by QCA between 50% and <70%, the proportion of gadobutrol injection-CMRI positive detections of CAD ranged from 15% to 33% . In Study F, among the 45 patients with maximum stenosis by QCA between 50% and < 70%, the proportion of gadobutrol injection-CMRI positive detections of CAD ranged from 20% to 35%. The results of gadobutrol injection-CMRI reads to detect CAD in patients with maximum stenosis between 50% and < 70% are summarized in Table 14.

* Stenosis determined by Quantitative Coronary Angiography (QCA).
**CMRI images were assessed by six independent blinded readers, three in each study.

Left Mainstem Stenosis (LMS)

The studies did not include sufficient numbers of subjects to characterize the performance of gadobutrol injection CMRI for detection of LMS, a subgroup at high risk from false negative reads. In Studies E and F, only three subjects had isolated LMS stenosis >50%. In two of the three cases, the CMRI was interpreted as normal by at least two of the three readers (false negative). Sixteen subjects had LMS stenosis >50% (including subjects with isolated LMS stenosis and subjects with LMS stenosis in addition to stenoses elsewhere). In five of these sixteen cases, the CMR was interpreted as normal by at least two of the three readers (false negative).

16.1 How Supplied

Gadobutrol injection is a sterile, clear and colorless to pale yellow solution containing 604.72 mg gadobutrol per mL (equivalent to 1 mmol gadobutrol) per mL. Gadobutrol injection is supplied in the following sizes:

16.2 Storage and Handling

Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature].

Should freezing occur, gadobutrol injection should be brought to room temperature before use. If allowed to stand at room temperature, gadobutrol injection should return to a clear and colorless to pale yellow solution. Visually inspect gadobutrol injection for particulate matter and discoloration prior to administration. Do not use the solution if it is discolored, if particulate matter is present or if the container appears damaged.