UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

(Amendment No. 2)*

Alexza Pharmaceuticals, Inc.

(Name of Issuer)

Common Stock, $0.0001 par value per share

(Title of Class of Securities)

015384 10 0

(CUSIP Number)

December 31, 2009

(Date of Event Which Requires Filing of This Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

     o     Rule 13d-1(b)

     þ     Rule 13d-1(c)

     o     Rule 13d-1(d)

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

TABLE OF CONTENTS

	Item 1(a). Name of Issuer
	Item 1(b), Address of Issuer’s Principal Executive Offices
	Item 2(a). Name of Person(s) Filing
	Item 2(b). Address of Principal Business Office
	Item 2(c) Citizenship
	Item 2(d) Title of Class of Securities
	Item 2(e) CUSIP Number
	Item 3. If This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a
	Item 4 Ownership
	Item 5 Ownership of Five Percent or Less of a Class
	Item 6 Ownership of More Than Five Percent on Behalf of Another Person
	Item 7 Identification and Classification of the Subsidiary which Acquired the Security Being Reported on by the Parent Holding Company
	Item 8 Identification and Classification of Members of the Group
	Item 9 Notice of Dissolution of Group
	Item 10 Certification
SIGNATURE

CUSIP No. 015384 10 0  13 G  Page 2  of   12  pages 

1	NAMES OF REPORTING PERSONS.
	Alejandro C. Zaffaroni, Ph.D.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
	(a)   o
	(b)   þ
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	United States of America
		5	SOLE VOTING POWER
NUMBER OF			0 shares
SHARES		6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			2,123,033 shares 1, 2, 3
EACH		7	SOLE DISPOSITIVE POWER
REPORTING
PERSON			0 shares
WITH		8	SHARED DISPOSITIVE POWER
			2,123,033 shares 1, 2, 3
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	2,123,033 shares 1, 2, 3
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
	4.1%4
12	TYPE OF REPORTING PERSON*
	IN

¹   By virtue of their status as trustees of the Zaffaroni Revocable Trust u/t/d 1/24/86 (the “Trust”), each of Alejandro C. Zaffaroni and his wife, Lida Zaffaroni, may be deemed to have shared beneficial ownership of the 1,831,626 shares held by the Trust.

²   By virtue of his status as a general and limited partner of the Zaffaroni Partners, L.P. (“Partners”), Alejandro C. Zaffaroni, Ph.D. may be deemed to have shared beneficial ownership of the 269,090 shares held by Partners.

³   By virtue of his status as trustee of each of the Alejandro Zaffaroni Retirement Trust FBO M. Lorette Viaud, the Alejandro Zaffaroni Retirement Trust FBO Donna Swanson and the Alejandro Zaffaroni Retirement Trust FBO Gonzalo M. Silveira (collectively, the “Retirement Trusts”), Alejandro C. Zaffaroni may be deemed to have shared beneficial ownership of an aggregate of 22,317 shares held by the Retirement Trusts.

⁴   This percentage is calculated based upon 52,411,356 shares of the Issuer’s common stock outstanding as of December 31, 2009.

CUSIP No. 015384 10 0  13 G  Page 3  of   12  pages 

1	NAMES OF REPORTING PERSONS.
	Zaffaroni Revocable Trust u/t/d 1/24/86
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
	(a)   o
	(b)   þ
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	California
		5	SOLE VOTING POWER
NUMBER OF			1,831,626 shares 5
SHARES		6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			0 shares
EACH		7	SOLE DISPOSITIVE POWER
REPORTING
PERSON			1,831,626 shares 5
WITH		8	SHARED DISPOSITIVE POWER
			0 shares
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	1,831,626 shares 5
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
	3.5%6
12	TYPE OF REPORTING PERSON*
	OO

⁵   By virtue of their status as trustees of the Zaffaroni Revocable Trust u/t/d 1/24/86 (the “Trust”), each of Alejandro C. Zaffaroni and his wife, Lida Zaffaroni, may be deemed to have shared beneficial ownership of the 1,831,626 shares held by the Trust.

⁶   This percentage is calculated based upon 52,411,356 shares of the Issuer’s common stock outstanding as of December 31, 2009.

CUSIP No. 015384 10 0  13 G  Page 4  of   12  pages 

1	NAMES OF REPORTING PERSONS
	Zaffaroni Partners, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
	(a)   o
	(b)   þ
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	California
		5	SOLE VOTING POWER
NUMBER OF			269,090 shares 7
SHARES		6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			0 shares
EACH		7	SOLE DISPOSITIVE POWER
REPORTING
PERSON			269,090 shares 7
WITH		8	SHARED DISPOSITIVE POWER
			0 shares
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	269,090 shares 7
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
	0.5% 8
12	TYPE OF REPORTING PERSON*
	PN

⁷   By virtue of his status as a general and limited partner of the Zaffaroni Partners, L.P. (“Partners”), Alejandro C. Zaffaroni, Ph.D. may be deemed to have shared beneficial ownership of the 269,090 shares held by Partners.

⁸   This percentage is calculated based upon 52,411,356 shares of the Issuer’s common stock outstanding as of December 31, 2009.

CUSIP No. 015384 10 0  13 G  Page 5  of   12  pages 

1	NAMES OF REPORTING PERSONS
	Alejandro C. Zaffaroni Retirement Trust FBO M. Lorette Viaud
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
	(a)   o
	(b)   þ
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	California
		5	SOLE VOTING POWER
NUMBER OF			2,727 shares 9
SHARES		6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			0 shares
EACH		7	SOLE DISPOSITIVE POWER
REPORTING
PERSON			2,727 shares 9
WITH		8	SHARED DISPOSITIVE POWER
			0 shares
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	2,727 shares 9
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
	0.01%10
12	TYPE OF REPORTING PERSON*
	OO

⁹   By virtue of his status as trustee of the Alejandro Zaffaroni Retirement Trust FBO M. Lorette Viaud, Alejandro C. Zaffaroni may be deemed to have shared beneficial ownership of the shares held by the trust.

¹⁰  This percentage is calculated based upon 52,411,356 shares of the Issuer’s common stock outstanding as of December 31, 2009.

CUSIP No. 015384 10 0  13 G  Page 6  of   12  pages 

1	NAMES OF REPORTING PERSONS
	Alejandro C. Zaffaroni Retirement Trust FBO Donna Swanson
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
	(a)   o
	(b)   þ
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	California
		5	SOLE VOTING POWER
NUMBER OF			3,090 shares 11
SHARES		6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			0 shares
EACH		7	SOLE DISPOSITIVE POWER
REPORTING
PERSON			3,090 shares 11
WITH		8	SHARED DISPOSITIVE POWER
			0 shares
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	3,090 shares 11
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
	0.01%12
12	TYPE OF REPORTING PERSON*
	OO

¹¹   By virtue of his status as trustee of the Alejandro Zaffaroni Retirement Trust FBO Donna Swanson, Alejandro C. Zaffaroni may be deemed to have shared beneficial ownership of the shares held by the trust.

¹²   This percentage is calculated based upon 52,411,356 shares of the Issuer’s common stock outstanding as of December 31, 2009.

CUSIP No. 015384 10 0  13 G  Page 7  of   12  Pages 

1	NAMES OF REPORTING PERSONS
	Alejandro C. Zaffaroni Retirement Trust FBO Gonzalo M. Silveira
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
	(a)   o
	(b)   þ
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	California
		5	SOLE VOTING POWER
NUMBER OF			16,500 shares 13
SHARES		6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			0 shares
EACH		7	SOLE DISPOSITIVE POWER
REPORTING
PERSON			16,500 shares 13
WITH		8	SHARED DISPOSITIVE POWER
			0 shares
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	16,500 shares 13
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
	0.03%14
12	TYPE OF REPORTING PERSON*
	OO

¹³   By virtue of his status as trustee of the Alejandro Zaffaroni Retirement Trust FBO Gonzalo M. Silveira, Alejandro C. Zaffaroni may be deemed to have shared beneficial ownership of the shares held by the trust.

¹⁴   This percentage is calculated based upon 52,411,356 shares of the Issuer’s common stock outstanding as of December 31, 2009.

Item 1(a). Name of Issuer:

Alexza Pharmaceuticals, Inc.

Item 1(b), Address of Issuer’s Principal Executive Offices:

2091 Stierlin Court
Mountain View, California 94043

Item 2(a). Name of Person(s) Filing:

Alejandro C. Zaffaroni, Ph.D.
Zaffaroni Revocable Trust u/t/d 1/24/86
Zaffaroni Partners, L.P.
Alejandro Zaffaroni Retirement Trust FBO M. Lorette Viaud
Alejandro Zaffaroni Retirement Trust FBO Donna Swanson
Alejandro Zaffaroni Retirement Trust FBO Gonzalo M. Silveira

Item 2(b). Address of Principal Business Office:

2600 El Camino Real, Suite 401
Palo Alto, CA 94306

Item 2(c) Citizenship:

Alejandro C. Zaffaroni, Ph.D.	United States of America
Zaffaroni Revocable Trust u/t/d 1/24/86	California
Zaffaroni Partners, L.P.	California Limited Partnership
Alejandro Zaffaroni Retirement Trust FBO M. Lorette Viaud	California
Alejandro Zaffaroni Retirement Trust FBO Donna Swanson	California
Alejandro Zaffaroni Retirement Trust FBO Gonzalo M. Silveira	California

Item 2(d) Title of Class of Securities:

Common Stock, $0.001 par value per share

Item 2(e) CUSIP Number:

015384 10 0

Item 3. If This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a:

Not applicable.

Page 8 of 12 pages

Item 4 Ownership.

Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1:

(a) Amount Beneficially Owned:
Alejandro C. Zaffaroni, Ph.D.	2,123,033	1, 2 3
Zaffaroni Revocable Trust u/t/d 1/24/86	1,831,626
Zaffaroni Partners, L.P.	269,090
Alejandro Zaffaroni Retirement Trust FBO M. Lorette Viaud	2,727
Alejandro Zaffaroni Retirement Trust FBO Donna Swanson	3,090
Alejandro Zaffaroni Retirement Trust FBO Gonzalo M. Silveira	16,500
(b) Percent of Class:
Alejandro C. Zaffaroni, Ph.D.	4.1	%1, 2, 3, 4
Zaffaroni Revocable Trust u/t/d 1/24/86	3.5	% 4
Zaffaroni Partners, L.P.	0.5	% 4
Alejandro Zaffaroni Retirement Trust FBO M. Lorette Viaud	0.01	% 4
Alejandro Zaffaroni Retirement Trust FBO Donna Swanson	0.01	% 4
Alejandro Zaffaroni Retirement Trust FBO Gonzalo M. Silveira	0.03	% 4
(c) Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
Alejandro C. Zaffaroni	0
Zaffaroni Revocable Trust u/t/d 1/24/86	1,831,626
Zaffaroni Partners, L.P.	269,090
Alejandro Zaffaroni Retirement Trust FBO M. Lorette Viaud	2,727
Alejandro Zaffaroni Retirement Trust FBO Donna Swanson	3,090
Alejandro Zaffaroni Retirement Trust FBO Gonzalo M. Silveira	16,500

1	By virtue of their status as trustees of the Zaffaroni Revocable Trust u/t/d 1/24/86 (the “Trust”), each of Alejandro C. Zaffaroni and his wife, Lida Zaffaroni, may be deemed to have shared beneficial ownership of the 1,831,626 shares held by the Trust.
2	By virtue of his status as a general and limited partner of the Zaffaroni Partners, L.P. (“Partners”), Alejandro C. Zaffaroni, Ph.D. may be deemed to have shared beneficial ownership of the 269,090 shares held by Partners.
3	By virtue of his status as trustee of each of the Alejandro Zaffaroni Retirement Trust FBO M. Lorette Viaud, the Alejandro Zaffaroni Retirement Trust FBO Donna Swanson and the Alejandro Zaffaroni Retirement Trust FBO Gonzalo M. Silveira (collectively, the “Retirement Trusts”), Alejandro C. Zaffaroni may be deemed to have shared beneficial ownership of an aggregate of 22,317 shares held by the Retirement Trusts.
4	This percentage is calculated based upon 52,411,356 shares of the Issuer’s common stock outstanding as of December 31, 2009

Page 9 of 12 pages

(ii) Shared power to vote or to direct the vote:
Alejandro C. Zaffaroni	2,123,033	1, 2, 3
Zaffaroni Revocable Trust u/t/d 1/24/86	0
Zaffaroni Partners, L.P.	0
Alejandro Zaffaroni Retirement Trust FBO M. Lorette Viaud	0
Alejandro Zaffaroni Retirement Trust FBO Donna Swanson	0
Alejandro Zaffaroni Retirement Trust FBO Gonzalo M. Silveira	0
(iii) Sole power to dispose or to direct the disposition of:
Alejandro C. Zaffaroni	0
Zaffaroni Revocable Trust u/t/d 1/24/86	1,831,626
Zaffaroni Partners, L.P.	269,090
Alejandro Zaffaroni Retirement Trust FBO M. Lorette Viaud	2,727
Alejandro Zaffaroni Retirement Trust FBO Donna Swanson	3,090
Alejandro Zaffaroni Retirement Trust FBO Gonzalo M. Silveira	16,500
(iv) Shared power to dispose or to direct the disposition of:
Alejandro C. Zaffaroni	2,123,033	1, 2, 3
Zaffaroni Revocable Trust u/t/d 1/24/86	0
Zaffaroni Partners, L.P.	0
Alejandro Zaffaroni Retirement Trust FBO M. Lorette Viaud	0
Alejandro Zaffaroni Retirement Trust FBO Donna Swanson	0
Alejandro Zaffaroni Retirement Trust FBO Gonzalo M. Silveira	0

1	By virtue of their status as trustees of the Zaffaroni Revocable Trust u/t/d 1/24/86 (the “Trust”), each of Alejandro C. Zaffaroni and his wife, Lida Zaffaroni, may be deemed to have shared beneficial ownership of the 1,831,626 shares held by the Trust.
2	By virtue of his status as a general and limited partner of the Zaffaroni Partners, L.P. (“Partners”), Alejandro C. Zaffaroni, Ph.D. may be deemed to have shared beneficial ownership of the 269,090 shares held by Partners.
3	By virtue of his status as trustee of each of the Alejandro Zaffaroni Retirement Trust FBO M. Lorette Viaud, the Alejandro Zaffaroni Retirement Trust FBO Donna Swanson and the Alejandro Zaffaroni Retirement Trust FBO Gonzalo M. Silveira (collectively, the “Retirement Trusts”), Alejandro C. Zaffaroni may be deemed to have shared beneficial ownership of an aggregate of 22,317 shares held by the Retirement Trusts.

Item 5 Ownership of Five Percent or Less of a Class.

If this statement is being filed to report the fact that as of the date hereof, the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following: þ

Item 6 Ownership of More Than Five Percent on Behalf of Another Person.

Not applicable.

Page 10 of 12 pages

Item 7 Identification and Classification of the Subsidiary which Acquired the Security Being Reported on by the Parent Holding Company.

Not applicable.

Item 8 Identification and Classification of Members of the Group.

Not applicable.

Item 9 Notice of Dissolution of Group.

Not applicable.

Item 10 Certification.

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

Page 11 of 12 pages

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

February 16, 2010         
Date  

/s/ Alejandro C. Zaffaroni
Alejandro C. Zaffaroni, Ph.D.
Zaffaroni Revocable Trust u/t/d 1/24/86 By:     Alejandro C. Zaffaroni and           Lida Zaffaroni, as Trustees
By:	/s/ Alejandro C. Zaffaroni
	Alejandro C. Zaffaroni,
	Trustee
By:	/s/ Lida Zaffaroni
	Lida Zaffaroni, Trustee
Zaffaroni Partners, L.P.
By:	/s/ Alejandro C. Zaffaroni
	Alejandro C. Zaffaroni
	General Partner
Alejandro Zaffaroni Retirement Trust FBO M. Lorette Viaud
By:	/s/ Alejandro C. Zaffaroni
	Alejandro C. Zaffaroni,
	Trustee
Alejandro Zaffaroni Retirement Trust FBO Donna Swanson
By:	/s/ Alejandro C. Zaffaroni
	Alejandro C. Zaffaroni,
	Trustee
Alejandro Zaffaroni Retirement Trust FBO Gonzalo M. Silveira
By:	/s/ Alejandro C. Zaffaroni
	Alejandro C. Zaffaroni,
	Trustee

Page 12 of 12 pages