Exhibit A AGREEMENT REGARDING THE JOINT FILING OF SCHEDULE 13DAgreement Regarding the Joint Filing of Schedule 13d • September 10th, 2015 • Polaris Venture Partners V, L.P. • Pharmaceutical preparations
Contract Type FiledSeptember 10th, 2015 Company 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.