A Children’s Hospital of Philadelphia (CHOP) start-up has been acquired by Roche Holding AG for $4.8 billion, leading to a $456 million payday for the hospital.

The windfall may offer lessons to other tech transfer organizations that are more risk-averse. CHOP took a big gamble on the now-unicorn start-up, Spark Therapeutics, agreeing to invest $50 million and becoming the biggest shareholder, which stood at 10.6% at the time of the sale. The hospital ultimately invested a total of $33 million. The company developed a new treatment for a rare form of blindness that was based on the research of hospital scientists; it went public in January 2015 and won approval for its first drug in December 2016. Roche agree to pay $114.50 per share for Spark.

According to Henry Bienen, president emeritus of Northwestern University, “you can count on one hand deals where a hospital or university made $400 or $500 million bucks.” Northwestern was one of those few, raking in $700 million for most of its royalty stream from the blockbuster drug Lyrica in a 2007 monetization deal with Royalty Pharma.

Combined with earlier share sales of $285 million, the acquisition by Roche has returned a total of $741 million to CHOP — a more than 20-fold ROI in less than six years — according to data compiled by Bloomberg.

Madeline Bell, CEO of Children’s Hospital of Philadelphia, says that Spark was launched to both accelerate gene therapy commercialization “and to create a new stream of funding for future scientific discovery.”

Analysts project that Spark’s lead product Luxturna will reap $76 million in sales this year, though Roche’s key gain from the acquisition may be a gene-therapy product for hemophilia that has yet to hit the market.

Source: Yahoo! Finanace