TAUVID Solution for injection Ref.[10075] Active ingredients:

The relationship between flortaucipir F 18 plasma concentrations and image interpretation was not explored in clinical trials.

Effect of MAO Inhibitors on Flortaucipir Binding in AD Patients

TAUVID PET signal was slightly reduced by rasagiline, a MAO-B inhibitor, in vivo in low tau, high MAO-B areas of the brain such as the nucleus accumbens, putamen, and caudate. However, there is little potential for MAO binding to affect TAUVID scan interpretation in neocortical areas.

After intravenous administration of TAUVID, flortaucipir F 18 was distributed throughout the body with less than 10% of the injected F 18 radioactivity present in the blood by 5 minutes following administration, and less than 5% present in the blood by 10 minutes after administration. The residual F 18 in circulation during the 80-minute to 100-minute imaging window was approximately 28% to 34% parent, with the remainder being metabolites.

Clearance occurs primarily by hepatobiliary and renal excretion.

Animal studies to assess the carcinogenicity or reproductive toxicity potentials of flortaucipir F 18 have not been conducted.

In an in vitro bacterial reverse mutation assay (Ames test), increases in the number of revertant colonies were observed in 4 of the 5 strains exposed to flortaucipir F 19. In a chromosomal aberration in vitro study with Chinese hamster ovary (CHO) cells, flortaucipir F 19 increased the percent of cells with structural aberrations with 3 hour exposure with or without S9 metabolic activation. Twenty hour exposure without activation produced an increase in structural aberrations at all tested concentrations.

Flortaucipir F 19 was evaluated in a rat micronucleus study and showed no genotoxicity. In this study, flortaucipir F 19 did not increase the number of micronucleated polychromatic erythrocytes at the highest achievable dose level, 1600 μg/kg/day, when given for two consecutive days.

The performance of TAUVID imaging to estimate the density and distribution of aggregated tau neurofibrillary tangles (NFTs) was evaluated in two clinical studies: Study 1 (NCT02516046) and Study 2 (NCT03901092). In each study, TAUVID imaging was interpreted by 5 independent readers who were blinded to clinical information. Readers interpreted TAUVID imaging as positive or negative [see Dosage and Administration (2.6)].

Study 1 enrolled 156 terminally ill patients who agreed to undergo TAUVID imaging and to participate in a postmortem brain donation program. In 64 of these patients, reader interpretation of the TAUVID scan was compared to tau pathology based on scoring provided by independent pathologists, who evaluated the density and distribution of NFTs in the post-mortem brain (see Table 5). Of the 64 patients, the mean age was 83 years (range 55 to 100); 34 were female; 49 had dementia, 1 had mild cognitive impairment, and 14 had no cognitive impairment on clinical evaluation around the time of TAUVID imaging.

Table 5. Study 1 Tau Pathology Scoring:

Image reader performance for distinguishing B3 (positive) from B0-B2 (negative) tau pathology is shown in Table 6.

Table 6. Study 1 TAUVID Scan Reader Performance for B3 Tau Pathology:

^a CI = confidence interval

The performance of the five TAUVID readers for sensitivity (95% CI) ranged from 92% (80, 97) to 100% (91, 100) and for specificity (95% CI) ranged from 52% (34, 70) to 92% (75, 98). Exploratory analysis evaluated how the same TAUVID interpretations distinguished B2-B3 from B0-B1 tau pathology, a threshold used in integrating tau and amyloid pathology for the neuropathological diagnosis of AD. In this analysis, the performance of the five TAUVID readers for sensitivity (95% CI) ranged from 68% (55, 79) to 86% (74, 93) and for specificity (95% CI) ranged from 63% (31, 86) to 100% (68, 100) [see Warnings and Precautions (5.1)].

Study 2 included the same terminally ill patients as in Study 1 (plus 18 additional terminally ill patients) and 159 patients with cognitive impairment being evaluated for AD (the indicated population). Inter-reader agreement for five new TAUVID readers was evaluated using Fleiss' kappa statistic (95% CI) and found to be 0.87 (0.83, 0.91) across all 241 patients. Exploratory analysis evaluated inter-reader agreement in two subgroups. In this analysis, Fleiss' kappa (95% CI) was 0.82 (0.75, 0.88) in the terminally ill patients and 0.90 (0.85, 0.95) in the indicated population.