FDA approves Onpattro for hereditary transthyretin-mediated amyloidosis.- Alnylam Pharma.

The FDA has approved Onpattro (patisiran) infusion, from Alnylam Pharmaceuticals, for the treatment of peripheral nerve disease (polyneuropathy) caused by hereditary transthyretin-mediated amyloidosis (hATTR) in adult patients. This is the first FDA-approved treatment for patients with polyneuropathy caused by hATTR, a rare, debilitating and often fatal genetic disease characterized by the buildup of abnormal amyloid protein in peripheral nerves, the heart and other organs. It is also the first FDA approval of a new class of drugs called small interfering ribonucleic acid (siRNA) treatment.

The efficacy of Onpattro was shown in a clinical trial involving 225 patients, 148 of whom were randomly assigned to receive an Onpattro infusion once every three weeks for 18 months, and 77 of whom were randomly assigned to receive a placebo infusion at the same frequency. The patients who received Onpattro had better outcomes on measures of polyneuropathy including muscle strength, sensation (pain, temperature, numbness), reflexes and autonomic symptoms (blood pressure, heart rate, digestion) compared to those receiving the placebo infusions. Onpattro-treated patients also scored better on assessments of walking, nutritional status and the ability to perform activities of daily living.

The most common adverse reactions reported by patients treated with Onpattro are infusion-related reactions including flushing, back pain, nausea, abdominal pain, dyspnea (difficulty breathing) and headache. All patients who participated in the clinical trials received premedication with a corticosteroid, acetaminophen, and antihistamines (H1 and H2 blockers) to reduce the occurrence of infusion-related reactions. Patients may also experience vision problems including dry eyes, blurred vision and eye floaters (vitreous floaters). Onpattro leads to a decrease in serum vitamin A levels, so patients should take a daily Vitamin A supplement at the recommended daily allowance.