Dicerna Pharmaceuticals (DRNA) SC 13G/A Dicerna Pharmaceuticals Inc

Exhibit 1

JOINT FILING STATEMENT

PURSUANT TO RULE 13D-1(K)(1)

The undersigned hereby consent and agree to the joint filing of Schedule 13G Amendment No.4 under the Securities Exchange Act of 1934, as amended, with respect to the Common Stock, par value  $0.0001 per share, of Dicerna Pharmaceuticals, Inc., together with any or all amendments thereto, when and if appropriate. The parties hereto further consent and agree to file this Joint Filing Statement pursuant to Rule13d-1(k)(1)(iii) as an exhibit to Schedule 13G, thereby incorporating the same into such Schedule13G.

This Joint Filing Statement may be terminated by any of the undersigned upon written notice or such lesser period of notice as the undersigned may mutually agree.

Dated: February 14, 2019

RTW Investments, LP
By:	/s/ Roderick Wong
	Roderick Wong, Managing Partner
RTW Master Fund, Ltd.
By:	/s/Roderick Wong
	Roderick Wong, Director
Roderick Wong
By:	/s/ Roderick Wong
	Roderick Wong, Individually