Bellus Health (BLU) SC 13G BELLUS Health / Artal International S.C.A. ownership change

EXHIBIT 1

JOINT FILING AGREEMENT

The undersigned agree that the statement on Schedule 13G with respect to the common shares of BELLUS Health Inc., dated as of December 4, 2020, is, and any amendments thereto signed by each of the undersigned shall be, filed on behalf of each of them pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended.

INVUS PUBLIC EQUITIES, L.P.
By:	INVUS PUBLIC EQUITIES ADVISORS, LLC, its general partner
By:	/s/ Raymond Debbane
Name:	Raymond Debbane
Title:	President
INVUS PUBLIC EQUITIES ADVISORS, LLC
By:	/s/ Raymond Debbane
Name:	Raymond Debbane
Title:	President
ARTAL TREASURY LIMITED
By:	/s/ Keith Le Poidevin
Name:	Keith Le Poidevin
Title:	Director
ARTAL INTERNATIONAL S.C.A.
By:	ARTAL INTERNATIONAL MANAGEMENT S.A., its managing partner
By:	/s/ Anne Goffard
Name:	Anne Goffard
Title:	Managing Director
ARTAL INTERNATIONAL MANAGEMENT S.A.
By:	/s/ Anne Goffard
Name:	Anne Goffard
Title:	Managing Director
ARTAL GROUP S.A.
By:	/s/ Anne Goffard
Name:	Anne Goffard
Title:	Authorized Person

WESTEND S.A.

By:	/s/ Pascal Minne
Name:	Pascal Minne
Title:	Director

STICHTING ADMINISTRATIEKANTOOR WESTEND

By:	/s/ Pascal Minne
Name:	Pascal Minne
Title:	Sole Member of the Board

MR. PASCAL MINNE

/s/ Pascal Minne

Dated: December 4, 2020