CNS Imaging

Efficacy and safety of gadoterate meglumine were evaluated in a multi-center clinical trial (Study A) that enrolled 364 adult and 38 pediatric patients (aged ≥ 2 years) with known or suspected CNS lesions. Adults were randomized 2 to 1 to receive either gadoterate meglumine or gadopentetate dimeglumine, each administered at a dose of 0.1 mmol/kg. All pediatric patients received gadoterate meglumine, also at a dose of 0.1 mmol/kg. In the trial, patients first underwent a baseline (pre-contrast) MRI examination followed by the assigned GBCA administration and a post-contrast MR examination. The images (pre-contrast, post-contrast and “paired pre- and post-contrast”) were interpreted by three independent off-site readers blinded to clinical information. The primary efficacy analysis compared three patient-level visualization scores (paired images) to baseline MRI (pre-contrast images) for adults who received gadoterate meglumine. The three primary visualization components were: contrast enhancement, border delineation and internal morphology. For each of these components there was a pre-defined scoring scale. Lesion counting (up to five per patient) was also reflected within each component’s patient-level visualization score.

Among the adult patients, 245 received gadoterate meglumine and their data comprised the primary efficacy population. There were 114 (47%) men and 131 (53%) women with a mean age of 53 years (range 18 to 85 years), the racial and ethnic representations were 84% Caucasian, 11% Asian, 4% Black, and 1% other.

Table 6 displays a comparison of paired images (pre- and post-contrast) to pre-contrast images with respect to the proportion of patients who had paired image scores that were greater “better”, or same/worse “not better” than the pre-contrast scores and with respect to the difference in the mean patient level visualization score. Across the three readers 56% to 94% of patients had improved lesion visualization for paired images compared to pre-contrast images. Gadoterate meglumine provided a statistically significant improvement for all three primary visualization components. More lesions were seen on the paired images than the pre-contrast images.

(a) Better: number of patients with paired (pre- and post-contrast) score greater than the pre-contrast score   
Not better: number of patients with paired score same as or worse than the pre-contrast score  
Missing: number of patients with missing score  
(b) Difference = paired mean score minus pre-contrast mean score   
*Statistically significant improvement by paired t-test

In secondary analyses, post-contrast images were improved in comparison to pre-contrast images. Gadoterate meglumine lesion visualization scores were similar to those for gadopentetate dimeglumine. Gadoterate meglumine imaging results in the pediatric patients were also similar to those seen in adults.

In a second clinical trial (Study B), MR images were reread from 150 adult patients with known CNS lesions who had participated in previously conducted clinical trial. Gadoterate meglumine administration and image interpretation was performed in the same manner as in Study A. Similar to Study A, this trial also demonstrated improved lesion visualization with gadoterate meglumine.

CNS Imaging in the Sub-population of Pediatric Patients Less than 2 years old

A non-randomized study (Study C) with 28 pediatric patients under 2 years of age who were referred for contrast MRI of the CNS supported extrapolation of CNS efficacy findings from adults and older children. CNS lesions were identified in 16 of these 28 patients on paired pre- and post-contrast images compared to 15 patients on pre-contrast images alone. In the 16 patients who had identifiable lesions, the scores for the co-endpoints of lesion visualization were improved for at least one lesion on paired pre- and post-contrast images compared to pre-contrast images in 8 out of 16 (50%) patients for lesion border delineation, 8 out of 16 (50%) patients for lesion internal morphology, and 14 out of 16 (88%) patients for lesion contrast enhancement.