DUBLIN – Spark Therapeutics Inc. is set to gain a European approval for Luxturna (voretigene neparvovec-rzyl), its gene therapy for treating retinal dystrophy arising from biallelic RPE65 mutations, following a positive vote Friday from the EMA's Committee on Human Medicinal Products (CHMP). Formal approval from the European Commission should follow in the coming months, which would trigger a $25 million milestone payment from Novartis AG and the start of what could be a tortuous series of reimbursement negotiations with the national health authorities of individual European Union member states.