CUSIP # 62957M104

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EXHIBIT A

Agreement of Joint Filing

The undersigned hereby agree that a single Schedule 13G (or any amendment thereto) relating to the common stock of the Issuer shall be filed on behalf of each of the undersigned and that this Agreement shall be filed as an exhibit to such Schedule 13G.

Date: September 28, 2015

Global Life Bioventure IV, S.à r.l.
By:	/s/ Richard Lim
Name:	Richard Lim
Title:	Class A Manager
By:	/s/ Eddy Dôme
Name:	Eddy Dôme
Title:	Class B Manager
Omega Fund IV, L.P.
By:	Omega Fund IV GP, L.P.
Its:	General Partner
By:	Omega Fund IV GP Manager, Ltd.
Its:	General Partner
By:	/s/ Richard Lim
Name:	Richard Lim
Title:	Director
Omega Fund IV GP, L.P.
By:	Omega Fund IV GP Manager, Ltd.
Its:	General Partner
By:	/s/ Richard Lim
Name:	Richard Lim
Title:	Director
Omega Fund IV GP Manager, Ltd.
By:	/s/ Richard Lim
Name:	Richard Lim
Title:	Director

CUSIP # 62957M104

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Richard Lim
By:	/s/ Richard Lim
Name:	Richard Lim
Otello Stampacchia
By:	/s/ Otello Stampacchia
Name:	Otello Stampacchia
Anne-Mari Paster
By:	/s/ Anne-Mari Paster
Name:	Anne-Mari Paster