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Forms and Documents

Below, you can find materials about Alnylam Assist® and treatment with ONPATTRO® (patisiran).
If you have any questions, call Alnylam Assist® at: 1-833-256-2748 (8am - 6pm ET, Monday-Friday).

Letter of Medical Necessity

Sample Letter of Medical Necessity >

This sample letter is provided for your guidance only. It provides an example of the types of information that may be provided when responding to a request from a patient's insurance company to provide a letter of medical necessity for ONPATTRO. Use of the information in this letter does not guarantee that the health plan will provide reimbursement for ONPATTRO and is not intended to be a substitute for or to influence the independent medical judgment of the physician.


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Learn more about how Alnylam Assist® supports
patients being treated with ONPATTRO® (patisiran).

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Important Safety Information

Infusion-Related Reactions

Infusion-related reactions (IRRs) have been observed in patients treated with ONPATTRO® (patisiran). In a controlled clinical study, 19% of ONPATTRO-treated patients experienced IRRs, compared to 9% of placebo-treated patients. The most common symptoms of IRRs with ONPATTRO were flushing, back pain, nausea, abdominal pain, dyspnea, and headache.

To reduce the risk of IRRs, patients should receive premedication with a corticosteroid, acetaminophen, and antihistamines (H1 and H2 blockers) at least 60 minutes prior to ONPATTRO infusion. Monitor patients during the infusion for signs and symptoms of IRRs. If an IRR occurs, consider slowing or interrupting the infusion and instituting medical management as clinically indicated. If the infusion is interrupted, consider resuming at a slower infusion rate only if symptoms have resolved. In the case of a serious or life-threatening IRR, the infusion should be discontinued and not resumed. 

Reduced Serum Vitamin A Levels and Recommended Supplementation

ONPATTRO treatment leads to a decrease in serum vitamin A levels. Supplementation at the recommended daily allowance (RDA) of vitamin A is advised for patients taking ONPATTRO. Higher doses than the RDA should not be given to try to achieve normal serum vitamin A levels during treatment with ONPATTRO, as serum levels do not reflect the total vitamin A in the body.

Patients should be referred to an ophthalmologist if they develop ocular symptoms suggestive of vitamin A deficiency (e.g. night blindness).

Adverse Reactions

The most common adverse reactions that occurred in patients treated with ONPATTRO were upper respiratory tract infections (29%) and infusion-related reactions (19%).


ONPATTRO is indicated for the treatment of the polyneuropathy of hereditary transthyretin-mediated amyloidosis in adults.

For additional information about ONPATTRO, please see the full Prescribing Information.