Spark Therapeutics, Inc. (ONCE) saw its loss widen to $123.65 million, or $4.29 a share for the year ended Dec. 31, 2016. In the previous year period, the company reported a loss of $47.13 million, or $2.10 a share.

Revenue during the year dropped 8.52 percent to $20.18 million from $22.06 million in the previous year.

Operating loss for the year was $125.40 million, compared with an operating loss of $47.32 million in the previous year.

"In 2016, we strengthened our gene therapy platform with proof-of-concept data validating two distinct target tissues - the retina and the liver - while continuing to expand our fully integrated capabilities," said Jeffrey D. Marrazzo, chief executive officer. "We are in the final stages of completing our rolling BLA submission for investigational voretigene neparvovec for biallelic RPE65-mediated inherited retinal disease (IRD). Another highlight of the year was the release of encouraging investigational SPK-9001 Phase 1/2 trial data that give us hope that we may be able to eliminate the need for regular infusions to control and prevent bleeding episodes for people living with hemophilia B. We look forward to continued innovation, execution and growth in 2017, which may be a historic year for Spark Therapeutics and for patients as we potentially deliver what has been unimaginable before - the first gene therapy in the U.S. for a genetic disease."

Days sales outstanding went up to 163 days for the year compared with 151 days for the same period last year.