Patient Selection

Perform baseline testing to select patients, including titer testing for Factor IX (FIX) inhibitor presence. Do not administer HEMGENIX^®, etranacogene dezaparvovec-drlb, to patients with FIX inhibitors or a history of FIX inhibitors. Perform liver health assessments, consulting with a hepatologist if needed. Also perform laboratory tests to evaluate hepatitis B and C, and postpone treatment if patient has active infection, as this may reduce the efficacy of HEMGENIX and/or increase the risk of adverse reactions.

Warnings and Precautions

Hypersensitivity and Infusion Reactions

Infusion reactions, including hypersensitivity reactions and anaphylaxis, have occurred. Monitor during administration and for at least 3 hours after end of infusion. If symptoms occur, slow or interrupt administration. When symptoms have resolved, restart administration at a slower infusion rate.

Hepatotoxicity/Hepatocellular Carcinogenicity

Hepatotoxicity with elevated liver transaminase has occurred after HEMGENIX treatment. Monitor ALT levels once per week for 3 months and thereafter monthly up to 1 year after administration. Consider corticosteroid treatment should elevations occur and as clinically indicated.

The integration of liver-targeting AAV vector DNA into the genome may carry the theoretical risk of hepatocellular carcinoma development. For patients with preexisting risk factors for hepatocellular carcinogenicity, consider liver ultrasound and alpha-fetoprotein testing following administration, and monitor for hepatocellular carcinomas for five years following administration of HEMGENIX.

Immune-Mediated Neutralization of the AAV5 vector capsid

Preexisting neutralizing anti-AAV antibodies may impede transgene expression at desired therapeutic levels. Following treatment with HEMGENIX, all patients developed neutralizing anti-AAV5 antibodies to AAV5 vector capsid.

Monitoring Laboratory Tests

Monitor patients regularly for FIX activity (eg, weekly for 3 months), especially when exogenous FIX is administered, as it may take several weeks following HEMGENIX administration before hemostatic control becomes apparent. Hemostatic support may be needed for some patients. Monitor patients through appropriate clinical observations and laboratory tests for the development of inhibitors to FIX.

Adverse Reactions

The most common adverse reactions (incidence ≥5% in clinical trials) are elevated ALT, headache, blood creatine kinase elevations, flu-like symptoms, infusion-related reactions, fatigue, nausea, malaise, and elevated AST.

Indication

HEMGENIX is indicated for the treatment of adults with Hemophilia B (congenital Factor IX deficiency) who:

• Currently use Factor IX prophylaxis therapy, or
• Have current or historical life-threatening hemorrhage, or
• Have repeated, serious spontaneous bleeding episodes.

HEMGENIX is for single-use intravenous infusion only.