Drug discovery company Ionis Pharmaceuticals Inc (NASDAQ:IONS) said on Friday that it has filed its marketing authorisation application (MAA) with the European Medicines Agency (EMA) for inotersen for patients suffering from hereditary TTR amyloidosis (hATTR), a severe, rare and fatal disease.

Based on the company's phase 3 NEURO-TTR study in patients with hereditary TTR amyloidosis (hATTR), the MAA for inotersen will be reviewed under the EMA's Accelerated Assessment programme, which is intended to expedite access to drugs that the EMA considers to be of major therapeutic interest.

The company stated Inotersen is an antisense drug designed to reduce the production of transthyretin, or TTR, to treat patients with TTR amyloidosis (ATTR). TTR builds up as fibrils in tissues and as the TTR protein fibrils enlarge, more tissue damage occurs and the disease worsens, resulting in poor quality of life and eventually death.

Under the Phase 3 NEURO-TTR study in patients with polyneuropathy due to hereditary TTR amyloidosis (hATTR), the company identified two key safety issues: the Norfolk Quality of Life Questionnaire-Diabetic Neuropathy (Norfolk QoL-DN) and the modified Neuropathy Impairment Score +7 (mNIS+7) at both eight and 15 months of treatment. Enhanced monitoring was implemented during the study to support early detection and management of these issues.

According to the company, the overall mortality rate in the NEURO-TTR study was 2.9% and was lower than mortality rates reported in other studies in hATTR patients.