On May 20, 2019, Sandra Zimmerman, Interim Vice President of Finance of Proteostasis Therapeutics, Inc., acting on behalf of Danforth Advisors pursuant to a Consulting Agreement, notified the Company of her intention to retire and resign as the Principal Financial and Principal Accounting Officer from the Company, effective May 31, 2019. Ms. Zimmerman’s resignation is for personal reasons and is not the result of any disagreement with the Company on any matter relating to the Company’s operations, policies or practices. Ms. Zimmerman is expected to continue to provide services to the Company as a consultant until May 31, 2019. On May 22, 2019, the Board of Directors of the Company appointed Eric Larson, the Company’s Controller, to serve as Principal Financial Officer and Principal Accounting Officer, effective May 31, 2019, until such time as his successor is appointed, or until his earlier resignation or removal. Mr. Larson, 49, has served as Controller since August 2018. From November 2014 through July 2018, Mr. Larson held various positions of increasing responsibility within Northern Power Systems, most recently as Vice President and Chief Accounting Officer. Prior to joining Northern Power Systems, he was the Controller at Spire Corporation from January 2014 to November 2014. From January 2013 to December 2013, Mr. Larson served as an Accounting Consultant at SmartBear Software. From March 2011 to November 2012, he served as the Director of Finance of Aspect Software. Prior to that, Mr. Larson held accounting and finance positions at various companies across a variety of sectors, including Biogen Idec, CMGI, Ernst & Young and Fidelity. Mr. Larson holds a B.A. in Accounting from Grove City College.