Ionis Pharmaceuticals, one of San Diego’s largest drugmakers, will have a new CEO in 2020.

Brett Monia, company’s chief financial officer, will assume the role, which is currently held by Stanley Crooke, who will become executive chairman.

Crooke formed Ionis Pharmaceuticals in 1989, which under his leadership grew to a $7 billion company with a broad drug development pipeline.

"I am very pleased with the state of Ionis today and I believe that in January 2020, when the transition will be effected, the company will be even stronger,” Crooke said in a statement.

Monia, a founding member of Ionis, has been an executive officer of the company since 2012 and became chief operating officer early this year. In addition, he was the company’s senior vice president of translational medicine, and the franchise leader for programs in oncology and rare diseases.

More than 40 Ionis drugs in clinical development fell under his supervision, multiple of which won regulatory approval, according to Ionis.

Ionis pioneered what are called antisense drugs that bind to RNA instead of proteins, which have long been the focus of the pharmaceutical industry. The approach notably yielded spinraza – a blockbuster drug for spinal muscular atrophy, a rare neuromuscular disorder.

The drug helped swing Ionis from an operating loss to profit in 2017.

“I am committed to ensuring that Ionis continues to advance these important medicines and our antisense platform, while continuing to build on the company's financial strength,” Monia said in a statement.

In a San Diego Business Journal profile of the company in May, Crooke reflected on the ups and downs as Ionis transformed into a major player. Such expansions and contractions are common in early to mid-stage biotechs.

“We have a whole presentation that we make to our folks just on our history. What happened, what went right, what went wrong, what we did that helped us survive, and how that informs what our future looks like. I could spend another day or two or three talking about all the disappointments and failure that we had,” Crooke told the Business Journal.