Exhibit 99.1

NEWS RELEASE - for immediate release

Alexza Announces Adasuve™ (Staccato^® Loxapine) PDUFA

Goal Date of December 21, 2012

Mountain View, California - July 5, 2012 - Alexza Pharmaceuticals, Inc. (Nasdaq: ALXA) announced today that the U.S. Food & Drug Administration (FDA) has accepted the Company’s resubmitted ADASUVE New Drug Application (NDA) as a complete, class 2 response to the FDA’s action letter, with an indicated Prescription Drug User Fee Act (PDUFA) goal date of December 21, 2012. On June 22, 2012, Alexza announced that it had resubmitted the ADASUVE NDA, which seeks marketing approval for the acute treatment of agitation associated with schizophrenia or bipolar I disorder in adults.

About Alexza Pharmaceuticals, Inc.

Alexza is a pharmaceutical company focused on the research, development and commercialization of novel, proprietary products for the acute treatment of central nervous system conditions. Alexza’s technology, the Staccato^® system, vaporizes unformulated drug to form a condensation aerosol that, when inhaled, allows for rapid systemic drug delivery through deep lung inhalation. With the Staccato system, a drug is quickly absorbed through the lungs into the bloodstream, providing speed of therapeutic onset that is comparable to intravenous administration, but with greater ease, patient comfort and convenience. (Click here to see an animation of how the Staccato system works.)

ADASUVE™ (Staccato loxapine) is Alexza’s lead program, which is being developed for the acute treatment of agitation associated with schizophrenia or bipolar I disorder in adults. Alexza completed and announced positive results from both of its Phase 3 clinical trials and initially submitted the ADASUVE NDA in December 2009. In October 2010, the Company received a complete response letter (CRL) from the FDA regarding the application. The Company completed an end-of-review meeting with the FDA in December 2010, a REMS guidance meeting with the FDA in April 2011, and the ADASUVE NDA was resubmitted in August 2011. In December 2011, the ADASUVE NDA was the subject of an advisory committee meeting. In January 2012, Alexza received notice of a 90-day extension of the PDUFA goal date, from February 4, 2012 to May 4, 2012. In May 2012, Alexza received a second CRL from the FDA regarding the ADASUVE NDA and on June 22, 2012, the Company resubmitted the ADASUVE NDA. The resubmitted ADASUVE NDA has a PDUFA goal date of December 21, 2012.

In October 2011, the Company established a commercial partnership for ADASUVE with Grupo Ferrer Internacional, S.A. Grupo Ferrer is a leading pharmaceutical company in Europe with extensive operations in the Americas, and is Alexza’s partner in the commercialization of ADASUVE

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in Europe, Latin America, Russia and the Commonwealth of Independent States countries. Alexza filed its ADASUVE Marketing Authorization Application (MAA) with the European Medicines Agency (EMA) in October 2011.

For more information about Alexza, the Staccato system technology or the Company’s development programs, please visit www.alexza.com. ADASUVE™ is a registered trademark of Alexza Pharmaceuticals, Inc.

Safe Harbor Statement

This press release contains forward-looking statements that involve significant risks and uncertainties. Any statement describing the Company’s expectations or beliefs is a forward-looking statement, as defined in the Private Securities Litigation Reform Act of 1995, and should be considered an at-risk statement. Such statements are subject to certain risks and uncertainties, particularly those inherent in the process of developing and commercializing drugs, including the adequacy of the Company’s capital to support the Company’s operations, the timing of the FDA’s review of the resubmitted ADASUVE NDA, the eventual prospects that ADASUVE will be approved for marketing in the U.S., and the timing and prospects for regulatory approval to market ADASUVE in Europe, Latin America, Russia and the Commonwealth of Independent States countries. The Company’s forward-looking statements also involve assumptions that, if they prove incorrect, would cause its results to differ materially from those expressed or implied by such forward-looking statements. These and other risks concerning Alexza’s business are described in additional detail in the Company’s Annual Report on Form 10-K for the year ended December 31, 2011 and the Company’s other Periodic and Current Reports filed with the Securities and Exchange Commission. Forward-looking statements contained in this announcement are made as of this date, and the Company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise.

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