Orphan designation: 2'-O-(2-Methoxyethyl) modified antisense oligonucleotide against MECP2 pre-mRNA Treatment of MECP2 duplication syndrome, 21/11/2025 Positive
Orphan designation: 2'-O-(2-Methoxyethyl) modified antisense oligonucleotide against MECP2 pre-mRNA Treatment of MECP2 duplication syndrome, 21/11/2025 Positive
Overview
This medicine was designated as an orphan medicine for the treatment of MECP2 Duplication Syndrome on 21 November 2025.
This means that the developer will receive scientific and regulatory support from EMA to advance their medicine to the stage where they can apply for a marketing authorisation.
Orphan designation does not mean the medicine is available or authorised for use. All medicines, including designated orphan medicines, must be authorised before they can be marketed and made available to patients in the EU.
During the medicine's development, doctors may be able to enrol patients in clinical trials investigating the medicine. For information on ongoing clinical trials in the EU, see:
Key facts
Active substance
2'-O-(2-Methoxyethyl) modified antisense oligonucleotide against MECP2 pre-mRNA
Intended use
Treatment of MECP2 duplication syndrome
Orphan designation status
Positive
EU designation number
EU/3/25/3152
Date of designation
21/11/2025
Sponsor
Ionis Development (Ireland) Limited
EMA list of opinions on orphan medicinal product designation
EMA publishes information on orphan medicinal product designation adopted by the Committee for Orphan Medicinal Products (COMP) on the IRIS online platform:
Patients' organisations
For contact details of patients’ organisations whose activities are targeted at rare diseases, see:
- European Organisation for Rare Diseases (EURORDIS), a non-governmental alliance of patient organisations and individuals active in the field of rare diseases.
- Orphanet, a database containing information on rare diseases, which includes a directory of patients’ organisations registered in Europe.
EU register of orphan medicines
The list of medicines that have received an orphan designation in the EU is available on the European Commission's website:
Summary
This medicine was designated as an orphan medicine for the treatment of MECP2 Duplication Syndrome on 21 November 2025. This means that the developer will receive scientific and regulatory support from EMA to advance their medicine to the stage where they can apply for a marketing authorisation. Orphan designation does not mean the medicine is available or authorised for use. All medicines, including designated orphan medicines, must be authorised before they can be marketed and made available to patients in the EU. During the medicine's development, doctors may be able to enrol patients in clinical trials investigating the medicine. For information on ongoing clinical trials in the EU, see: EU Clinical Trials Register ClinicalTrials.gov