The Food and Drug Administration (FDA) has issued a Complete Response Letter (CRL) to Biogen regarding the supplemental Biologics License Application (sBLA) for subcutaneous (SC) administration of Tysabri® (natalizumab).

Tysabri, an integrin receptor antagonist, is approved as monotherapy for the treatment of relapsing forms of multiple sclerosis (MS), to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease in adults. As there is an increased risk for progressive multifocal leukoencephalopathy, prior to initiating treatment, consideration should be given to whether the benefits of the drug are sufficient to offset this risk.

Currently, the FDA-approved route of administration of Tysabri for MS is through intravenous infusion. In the CRL, the Agency stated that the application for the new SC route of administration could not be approved in its current form.

“This response from the FDA does not affect the intravenous administration of Tysabri, a well-established high-efficacy treatment with a well-characterized safety profile, which over the last 15 years has treated more than 200,000 people worldwide with relapsing MS,” said Maha Radhakrishnan, MD, Chief Medical Officer at Biogen.


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In a statement, Biogen noted that the CRL is being evaluated to determine next steps. The Company recently received marketing authorization for the SC injection of Tysabri by the European Commission and is planning for additional regulatory filings in other countries.

Reference

 Biogen provides regulatory update on the supplemental Biologics License Application (sBLA) for subcutaneous administration of Tysabri® (natalizumab). [press release]. Cambridge, MA: Biogen Inc; April 28, 2021.