By Kimberly Chin and Kristin Broughton

Drugmaker Biogen Inc. has named Michael McDonnell, the current finance chief at drug-testing and data company Iqvia Holdings Inc., as its next chief financial officer.

Biogen's current finance chief Jeffrey Capello, 55, who has been in the position since December 2017, will step down. He is expected to stay on until Sept. 15 to help with the transition; Mr. McDonnell will start Aug. 15. The company didn't provide a reason for his exit.

Mr. McDonnell, 56, has served in the CFO role at Iqvia since December 2015. Iqvia, which offers contract research services, data and technology to the life-sciences industry, said Tuesday it has named Ron Bruehlman as its interim chief financial officer.

Before Iqvia, Mr. McDonnell was the CFO of satellite-services provider Intelsat Corp. and the chief financial officer of commercial-finance company MCG Capital Corp.

Biogen earlier this month said it completed an application with the U.S. Food and Drug Administration for approval of aducanumab, an Alzheimer's treatment. The drugmaker is betting the new Alzheimer's drug will fuel its revenue growth -- but the development has been marred by setbacks. The company in March 2019 terminated two late-stage studies of the experimental drug that it was pursuing with Eisai Co., saying the drug would fail to help patients. The company's shares tumbled roughly 30% on the news.

Biogen changed course in October, saying it would seek regulatory approval after being presented with new data about the drug's effectiveness.

The abrupt reversal raised questions among investors who wanted more clarity -- and were disappointed when they didn't get it, said Umer Raffat, an analyst who covers the company with Evercore ISI. "The communication around Alzheimer's has been by far, and will be the biggest challenge for the new CFO," Mr. Raffat said.

Write to Kimberly Chin at kimberly.chin@wsj.com and Kristin Broughton at Kristin.Broughton@wsj.com