General Information

Tegsedi (inotersen) is a transthyretin-directed antisense oligonucleotide. 

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

Tegsedi is supplied as a solution for subcutaneous injection. The recommended dose is 284 mg injected subcutaneously once weekly. For consistency of dosing, patients should be instructed to give the injection on the same day every week. If a dose is missed, patients should be instructed to take the missed dose as soon as possible, unless the next scheduled dose is within 2 days. In this situation, the patient should be directed to skip the missed dose and take the next scheduled dose on the scheduled day. 

Mechanism of Action

Tegsedi (inotersen) is an antisense oligonucleotide that causes degradation of mutant and wild-type TTR mRNA through binding to the TTR mRNA, which results in a reduction of serum TTR protein and TTR protein deposits in tissues.

Side Effects

Adverse events associated with the use of Tegsedi may include, but are not limited to, the following:

• injection site reactions
• nausea
• headache
• fatigue
• thrombocytopenia
• fever

The Tegsedi drug label comes with the following Black Box Warning: Thrombocytopenia: Tegsedi causes reductions in platelet count that may result in sudden and unpredictable thrombocytopenia, which can be life threatening. Testing prior to treatment and monitoring during treatment is required. Glomerulonephritis: Tegsedi can cause glomerulonephritis that may require immunosuppressive treatment and may result in dialysis dependent renal failure. Testing prior to treatment and monitoring during treatment is required.

Clinical Trial Results

The FDA approval of Tegsedi was based on data from the NEURO-TTR study, a Phase III randomized, double-blind, placebo-controlled, 15-month, international study in 172 patients with hATTR amyloidosis with symptoms of polyneuropathy. In NEURO-TTR, Tegsedi demonstrated significant benefit compared to placebo in measures of neuropathy and quality of life as measured by the modified Neuropathy Impairment Score +7 (mNIS+7) and in the Norfolk Quality of Life Questionnaire-Diabetic Neuropathy (Norfolk QOL-DN) total score. Additionally, Tegsedi eased symptoms in patients, compared with initial values at the beginning of the study. The benefits were associated with marked decreases in the level of TTR, with almost 90% of patients achieving over 50% TTR reduction, and nearly 50% achieving over 75% TTR reduction at 15 months.