Exhibit A AGREEMENT REGARDING THE JOINT FILING OF SCHEDULE 13DNew Leaf Ventures III, L.P. • October 11th, 2017 • Pharmaceutical preparations
Company FiledOctober 11th, 2017 IndustryThe undersigned, being duly authorized thereunto, hereby execute this agreement as an exhibit to this Schedule 13D to evidence the agreement of the below-named parties, in accordance with the rules promulgated pursuant to the Securities Exchange Act of 1934, to file this Schedule jointly on behalf of each such party.