Exhibit 99.1

Joint Filing Agreement

The undersigned hereby agree that the Statement on Schedule 13G, dated October 8, 2014 with respect to the shares of Common Stock of Assembly Biosciences, Inc. and any amendments thereto executed by each and any of the undersigned shall be filed on behalf of each of the undersigned pursuant to and in accordance with the provisions of Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended.

Dated:  October 8, 2014	EcoR1 Capital Fund, L.P.
	By:	EcoR1 Capital, LLC General Partner
	By:		/s/ Oleg Nodelman
			Name:	Oleg Nodelman
			Title:	Manager

EcoR1 Capital Fund Qualified, L.P.
By:	EcoR1 Capital, LLC General Partner
By:		/s/ Oleg Nodelman
		Name:	Oleg Nodelman
		Title:	Manager

EcoR1 Capital, LLC
By:	/s/ Oleg Nodelman
	Name:	Oleg Nodelman
	Title:	Manager

/s/ Oleg Nodelman

Oleg Nodelman