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What is AMONDYS 45 (casimersen)?

AMONDYS 45 is used to treat patients with Duchenne muscular dystrophy (DMD) who have a confirmed mutation of the dystrophin gene that can be treated by skipping exon 45.

This indication is approved under accelerated approval based on an increase in dystrophin production in skeletal muscle observed in patients treated with AMONDYS 45. Continued approval for this indication may be contingent upon verification of a clinical benefit in confirmatory trials.


Contraindication: Do not receive AMONDYS 45 if you are allergic to casimersen or any of the ingredients in AMONDYS 45. Serious allergic reactions to casimersen have included anaphylaxis, which may include difficulty breathing, tightness in the chest, and angioedema which may include swelling of the mouth, face, lips, or tongue.

Hypersensitivity Reactions: Serious allergic reactions, including angioedema and anaphylaxis, have occurred in patients who were treated with AMONDYS 45. Patients should seek immediate medical care should they experience signs and symptoms of hypersensitivity. Your doctor will institute appropriate medical treatment which may include slowing, interrupting, or discontinuing the AMONDYS 45 infusion. Your doctor will monitor you until the condition resolves.

Kidney Toxicity and Monitoring: Damage to the kidneys was seen in animals who received casimersen. Although damage to the kidneys was not seen in clinical studies with AMONDYS 45, potentially fatal kidney damage has occurred with other drugs that work in a similar way. Your doctor may recommend urine and blood testing before starting treatment followed by urine testing every month and a blood test every 3 months to monitor your kidneys.

Adverse reactions: Adverse reactions occurring in at least 20% of patients treated with AMONDYS 45 and at least 5% more frequently than in patients who received an inactive intravenous (IV) infusion were (AMONDYS 45, placebo): upper respiratory tract infection (65%, 55%), cough (33%, 26%), fever (33%, 23%), headache (32%, 19%), joint pain (21%, 10%), and pain in mouth and throat (21%, 7%).

Other adverse reactions that occurred in at least 10% of patients treated with AMONDYS 45 and at least 5% more frequently than patients who received an inactive intravenous (IV) infusion were: ear pain, nausea, ear infection, pain after injury, and dizziness and light-headedness.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit or call 1-800-FDA-1088. You may also report side effects to Sarepta Therapeutics at 1-888-SAREPTA (1-888-727-3782).

Please see the full Prescribing Information for AMONDYS 45 (casimersen).