Mr. Joseph Loscalzo, M.D., Ph.D. has been the Chairmen of the board since June 2021. Previously he served as the Non-Executive director of the board since 2014. He serves as the Chairman of the Department of Medicine and Physician-in-Chief at Brigham and Women’s Hospital.

Mr. Brett P. Monia has been the Director and the Chief Executive Officer of the company since January 2020. Previously, he served as the Chief Operating Officer and before that, he served as the Senior Vice President- Drug Discovery. Prior to this, he served as the Vice President, Preclinical Drug Discovery. Mr. Monia also held various positions within the company's Molecular Pharmacology Department.

Ms. Elizabeth L. Hougen has been the Executive Vice President of Finance and Chief Financial Officer of the company since January 2020. Previously, she served as Senior Vice President, Finance and Chief Financial Officer from 2013 to 2020. Prior to this, she served as the company's Vice President of Finance and Chief Accounting Officer from January 2007 to December 2012. Ms. Hougen also served as the Executive Director of Finance and Chief Financial Officer for Molecular Biosystems, Inc.

Mr. Darren Gonzales is Chief Accounting Officer, Senior Vice President of the company.

Mr. Patrick R. O’Neil has been the Chief Legal Officer, Corporate Secretary and General Counsel of the company since September 2021. Prior to this, he served as the Executive Vice President, Legal & General Counsel and Chief Compliance Officer since March 2020; and as the Vice President, Legal and Senior Transactions Counsel since January 2013. From October 2001 to January 2009 he held various positions within the company's Legal department. Prior to joining Ionis, Mr. O’Neil served at Cooley LLP.