Alexza Pharmaceuticals, Inc.

(Exact Name of Registrant as Specified in Charter)

Check the appropriate box to indicate the rule pursuant to which this form is being filed, and provide the period to which the information in this form applies:

x Rule 13p-1 under the Securities Exchange Act (17 CFR 240.13p-1) for the reporting period from January 1 to December 31, 2015.

Section 1—Conflict Minerals Disclosure

Item 1.01 Conflict Minerals Disclosure and Report

Conflict minerals, as defined by paragraph (d)(3) of this item, are necessary to the functionality or productions of a product manufactured by Alexza Pharmaceuticals, Inc. (referred to as “we”, “us”, or the “Company”) or contracted by the Company to be manufactured (the “Company’s Products”) as defined in Rule 13p-1 under the Securities Exchange Act of 1934, as amended (the “Rule”) and for which manufacturing was completed in the period from January 1, 2015 to December 31, 2015. Accordingly, we are filing this Form SD for the calendar year covered by this report, as required by the Rule.

We evaluated our current product lines and determined that certain product we manufacture or contract to manufacture contain tin, tungsten, tantalum and/or gold (3TG). We requested our manufacturers to complete a Reasonable County of Origin (“RCOI”) questionnaire for each such conflict mineral. The survey of our suppliers determined that our supply chain is Conflict Free Undeterminable and as a result we have filed a Conflict Minerals Report.

We recognize that the supply chain tracing of these materials is complex; however, we are committed to working with our suppliers to determine whether the products we manufacture or contract to manufacture are “conflict free,” that is, that they either do not contain conflict minerals from the Covered Countries or originate from recycled or scrap materials.

A copy of The Company’s Conflict Minerals Report is provided as Exhibit 1.01 hereto and is publicly available at: www.alexza.com under “Corporate Governance”.

Item 1.02 Exhibit

The Conflict Minerals Report required by Item 1.01 is filed as Exhibit 1.01 to this Form SD.

Section 2—Exhibits

Item 2.01 Exhibits

Exhibit 1.01—Conflict Minerals Report for Alexza Pharmaceuticals, Inc.

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 duly authorized undersigned.

Alexza Pharmaceuticals, Inc.

(Registrant)