(Reuters) - Spark Therapeutics Inc’s experimental gene therapy helped improve vision in patients with a type of inherited eye disorder in a late-stage study, bringing it a step closer to becoming the first gene therapy to win U.S. approval.
The drug developer’s shares jumped as much as 50.2 percent on Monday.
Spark said its lead drug, SPK-RPE65, met the goals of improving vision and sensitivity to light in patients with inherited retinal dystrophies (IRDs) who were previously at the risk of total blindness.
SPK-RPE65 is a form of gene therapy, a treatment which aims to insert corrective genes into malfunctioning cells. The study tested the drug in 31 patients with IRDs, a broad group of hereditary disorders affecting the retina.
While there is no currently approved treatments for IRDs, the results place Spark comfortably one step ahead of its gene-therapy rivals including Applied Genetic Technologies Corp, Avalanche Biotechnologies Inc and ReGenxbio Inc who are also developing their own eye treatments.
Spark expects to file for marketing approval in the United States in 2016. If approved, J.P.Morgan analysts expect it to rake in peak worldwide sales of about $600 million.
The drug, SPK-RPE65, could be worth about $65 per Spark share, Cowen and Co analysts noted last week.
Roth Capital Partners’ analyst Elemer Piros said he expects SPK-RPE65 to cost about $100,000 per patient per year, as long as the therapy provides lasting benefit.
Glybera, developed by Dutch biotech firm UniQure NV was the Western world’s first approved gene therapy, and has been cleared for reimbursement in Germany for a one-time payment of about $1 million.
Shares of the Philadelphia-based company have almost doubled since its IPO debut on Jan. 30.
Although gene therapy has been touted as a one-time cure for intractable and expensive-to-treat diseases, it has been dogged by a series of disappointments and safety concerns in its more than 20 years of research.
However, investor interest in the field has grown this year, with Bluebird Bio Inc, UniQure NV and Spark all staging successful Nasdaq debuts.
Spark’s pipeline also carries experimental treatments for other conditions including blood disorders and neurodegenerative diseases.
J.P.Morgan analysts also backed the potential of Spark’s other experimental eye therapy, SPK-CHM, which is being tested in patients with choroideremia, another type of IRD.
The SPK-CHM design is similar to SPK-RPE65 in terms of target cells, method of administration and manufacturing process, the only difference is the gene itself, the analysts said in a note.
If approved, J.P.Morgan analysts expect SPK-CHM to touch peak worldwide sales of about $1.6 billion.
Reporting by Samantha Kareen Nair in Bengaluru; Editing by Savio D'Souza and Shounak Dasgupta