BioCentury
ARTICLE | Finance

ONCE upon a time

Parsing Spark's rollercoaster week on positive Phase III gene therapy data

October 12, 2015 7:00 AM UTC

Last week's stock move by Spark Therapeutics Inc. (NASDAQ:ONCE) has its investors scratching their heads, as positive Phase III data did little to reignite interest in the ophthalmic gene therapy play. Instead, the stock remains more than 40% below its 52-week high of $79.50.

Spark jumped 21% to $53.02 last Monday when its SPK-RPE65 met the primary endpoint in a trial to treat RPE65-mediated inherited retinal dystrophies. But the company gave back those gains over Tuesday and Wednesday, then drifted up on Thursday and Friday to end the week at $49.30, up $5.37 (12%)...