Gene therapy for choroideremia granted orphan drug status

Both the U.S. FDA and the European Medicines Agency have granted orphan drug status to a gene therapy for choroideremia, according to NightstaRx.  

Developed by Professor Robert MacLaren of Oxford’s Nuffield Laboratory of Ophthalmology, the new therapy involves a subfoveal injection of an adeno-associated viral vector encoding the Rab escort protein 1, which these patients are missing. Initial results published last year in The Lancet show that therapy can be administered safely and that 2 of the 6 patients enrolled experienced improved vision.

Two patients with advanced choroideremia and low baseline best corrected visual acuity gained 21 letters and 11 letters (more than 2 and 4 lines of vision). Four other patients with near normal best corrected visual acuity at baseline recovered to within 1 to 3 letters. Maximal sensitivity measured with dark-adapted microperimetry increased from 23.0 dB at baseline to 25.3 dB after treatment.