UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): June 23, 2015 (June 19, 2015)

ALEXZA PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (650) 944-7000

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Section 3 — Securities and Trading Markets

(a)

On June 19, 2015, Alexza Pharmaceuticals, Inc. (“Alexza”) received a notice (the “Notice”) from the Nasdaq Stock Market (“NASDAQ”) indicating that Alexza’s common stock (“Common Stock”) no longer meets the continued listing requirement as set forth in NASDAQ Rule 5550(b)(2) based on the market value of Alexza’s listed securities for the preceding 30 business days. The minimum market value of listed securities for continued listing on the Nasdaq Capital Market is $35 million.

Under NASDAQ Rule 5810(c)(3)(C), Alexza has a 180 calendar day grace period from the date of the Notice to regain compliance by meeting the continued listing standard. The continued listing standard will be met if the market value of Alexza’s listed securities closes at $35 million or more for a minimum of 10 consecutive business days during such grace period. If Alexza is unable to regain compliance during the 180 calendar day grace period and receives a delisting determination from NASDAQ it may, at that time, request a hearing to remain on The Nasdaq Capital Market, which request will ordinarily suspend such delisting determination until a decision by NASDAQ subsequent to the hearing.

There can be no assurance that Alexza will be successful in maintaining its listing of the Common Stock on The Nasdaq Capital Market. This could impair the liquidity and market price of the Common Stock. In addition, the delisting of the Common Stock from a national exchange could materially adversely affect Alexza’s access to capital markets, and any limitation on market liquidity or reduction in the price of the Common Stock as a result of that delisting could adversely affect Alexza’s ability to raise capital on terms acceptable to Alexza, or at all.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.