Aceragen (ACGN) SC 13G Idera Pharmaceuticals, Inc.

EXHIBIT 99.1

JOING FILING AGREEMENT

In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended, the undersigned hereby agree that this Statement on Schedule 13G relating to the Common Stock of Idera Pharmaceuticals, Inc. is being filed with the Securities and Exchange Commission on behalf of each of them.

September 6, 2019

BAKER BROS. ADVISORS LP
By:	Baker Bros. Advisors (GP) LLC, its general partner
By:	/s/ Scott L. Lessing
	Name: Scott L. Lessing
	Title: President
BAKER BROS. ADVISORS (GP) LLC
By:	/s/ Scott L. Lessing
	Name: Scott L. Lessing
	Title: President
/s/ Julian C. Baker
Julian C. Baker
/s/ Felix J. Baker
Felix J. Baker
FBB3 LLC
/s/ Julian C. Baker
Julian C. Baker