Tegsedi (inotersen) for hATTR-PN
Fact-checked by What is Tegsedi for hATTR-PN?
Tegsedi (inotersen) is an injectable therapy for hereditary transthyretin amyloidosis with polyneuropathy (hATTR-PN) that was approved in the U.S., but then discontinued in 2024 by its developer Ionis Pharmaceuticals.
Given via weekly subcutaneous, or under-the-skin, injections, Tegsedi is a gene silencing therapy designed to reduce the production of the transthyretin protein in the body. That protein becomes unstable and harmfully accumulates in nerve cells outside the brain and spinal cord, driving the symptoms of hATTR-PN.
Clinical trial data demonstrated the therapy’s ability to ease hATTR-PN symptoms and slow disease progression. Common side effects are injection site reactions, nausea, headache, fatigue, low blood platelet counts (thrombocytopenia), and fever. The treatment came with a warning that it required advanced safety monitoring for thrombocytopenia and kidney toxicity.
Tegsedi was approved for treating adults with hATTR-PN in the U.S., Canada, and the European Union. It is now discontinued in both the U.S. and Canada. This decision was related to low utilization, and not quality, manufacturing, or safety concerns.
The medication is still marketed in Europe, where it is distributed by Sobi, and in Brazil, where it is marketed by PTC Therapeutics. Â
Therapy snapshot
| Treatment name | Tegsedi |
| Administration | Subcutaneous injection |
| Clinical testing | Received regulatory approval in U.S.; discontinued due to low usage |
Tegsedi in clinical trials
The primary study that supported regulatory approval of Tegsedi was the Phase 2/3 NEURO-TTR trial (NCT01737398). Adults with stage 1 or 2 hATTR-PN received weekly subcutaneous injections of the medication or a placebo for a slightly longer than one year, after three initial loading doses. The results showed that treatment:
- significantly eased symptoms of neuropathy and improved quality of life relative to the placebo
- slowed hATTR-PN progression, particularly in terms of muscle weakness and sensation loss
- reduced circulating transthyretin levels
At the end of the trial, participants could enter an open-label extension study (NCT02175004) in which all participants received weekly Tegsedi. Three-year results showed that the therapy was associated with a sustained slowing of neurological disease progression.
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