San Diego-based Ligand Pharmaceuticals Inc. has paid $3.5 million to acquire a portfolio of more than 15 biologic development programs from Geneva, Switzerland-based drugmaker Selexis SA, the company said in a regulatory filing.

Ligand will additionally pay $1 million more on the first anniversary of the closing, the company said.

The acquired assets will expand the company’s presence in the oncology and autoimmune disease drug markets, the company said.

Ligand’s shares dropped about 1 percent following the announcement on April 30, trading at $27.32 at market close. The company has a market capitalization of $552 million.

“This acquisition significantly expands Ligand's already robust portfolio to more than 85 fully-funded assets, and diversifies our portfolio beyond small molecule therapeutics into biologics,” said Ligand president and chief executive John Higgins in a statement. “The acquired rights are a great fit with our royalty-based business model, and the deal does not require operational integration or ongoing technical responsibilities from Ligand. We believe this acquisition reinforces the strength of our shots-on-goal strategy and has the potential to provide Ligand with numerous new drivers of long-term growth.”

— Meghana Keshavan