Alexza and Grupo Ferrer Amend Adasuve Partnership Alexza and Grupo Ferrer Amend Adasuve Partnership; Ferrer to Purchase 2.42M Shares of Alexza Common Stock for $1.24 per Share

Alexza Pharmaceuticals, Inc.

and Grupo Ferrer Internacional, S.A. (Ferrer), announced today that they have amended their commercial partnership agreement for Adasuve™ (Staccato® loxapine). In October 2011, Alexza and Ferrer established a partnership for the commercialization of ADASUVE in Europe, Latin America, Russia and the Commonwealth of Independent States countries. With this amendment, Ferrer will expand its strategic partnership by becoming an Alexza stockholder. Ferrer and Alexza have agreed to eliminate a future potential milestone payment in exchange for the purchase of Alexza common stock. Ferrer will purchase approximately 2.42 million shares of Alexza common stock for $1.24 per share. During 2012, up to an additional $8 million of Alexza common stock may be purchased by Ferrer, upon a request by Alexza and subject to acceptance by Ferrer, in exchange for the elimination of additional milestones at a price per share that will be a premium to the market price on the date of purchase.