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Drug Safety-related Labeling Changes (SrLC)

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MEPSEVII (BLA-761047)

(VESTRONIDASE ALFA-VJBK)

Safety-related Labeling Changes Approved by FDA Center for Drug Evaluation and Research (CDER)

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12/23/2020 (SUPPL-5)

Approved Drug Label (PDF)

6 Adverse Reactions

6.2 Immunogenicity

(Additions and/or revisions underlined)

As with all therapeutic proteins, there is potential for immunogenicity. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally,  the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies in the studies described below with the incidence of antibodies in other studies to other vestronidase alfa products may be misleading.

Immunogenicity data were available from 23 patients who received MEPSEVII for up to 187 weeks of treatment. Eighteen out of 23 (78%) patients developed anti-vestronidase alfa-vjbk antibodies (ADA). Ten of the 18 (55.6%) ADA-positive patients were tested positive for neutralizing antibodies (NAb).

There is no correlation between ADA titer and NAb development.

Six treatment-naïve patients had pre-existing ADA titers at baseline. ADAs were detected in five of these six patients post-treatment. The post-treatment ADA titers were the same as or below the baseline ADA titer values in two patients, but one of these two patients was positive for NAb. ADA titer values after treatment increased 64-fold, 128-fold, and 364-fold, respectively, in the other three patients.

The presence of ADA titer did not appear to affect reduction in urinary glycosaminoglycans (uGAGs).

12/06/2019 (SUPPL-3)

Approved Drug Label (PDF)

8 Use in Specific Populations

8.1 Pregnancy

(additions underlined)

Risk Summary

There are no available data on MEPSEVII use in pregnant women to determine a drug-associated risk of adverse developmental outcomes. In embryofetal development studies, vestronidase alfa-vjbk administered intravenously to pregnant rats and rabbits during the period of organogenesis showed , no adverse developmental outcomes at doses up to 1.6 and 10 times, respectively for rats and rabbits, the exposure at the recommended human dose. In a pre- and postnatal development study in rats, an increased number of stillbirths were observed at exposures less than the recommended human dose (see Data). The clinical relevance of these animal findings is uncertain.

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Data

Animal Data

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In a pre- and post-natal developmental study in rats, vestronidase alfa-vjbk was administered every 3 days from gestation day 7 through lacation day 20 at doses of 2 mg/kg, 6 mg/kg, and 20 mg/kg.

Mortality and adverse clinical signs were observed in the maternal animals at the 20 mg/kg dose (1.6 times the human exposure (AUC) at the recommended human dose of 4 mg/kg). Subsequently, the 20 mg/kg dose was reduced to 12 mg/kg. Maternal toxicity with mortality in one animal was also observed at the 6 mg/kg dose (0.17 times the AUC at the recommended human dose of 4 mg/kg). At the 2 mg/kg dose (0.01 times the AUC at the recommended human dose of 4 mg/kg), no adverse effects were observed in the maternal animals; however, there was a statistically significant decrease in the number of live births and subsequent increase in the number of stillbirths at this dose.