	SECURITIES AND EXCHANGE COMMISSION
	Washington, D.C. 20549

	SCHEDULE 13D

Under the Securities Exchange Act of 1934
(Amendment No. 4)

Talon Therapeutics, Inc.

(Name of Issuer)

COMMON STOCK, $.001 PAR VALUE PER SHARE

(Title of Class of Securities)

40963P105

(CUSIP Number)

Scott A. Arenare, Esq.

Managing Director and General Counsel

Warburg Pincus LLC

450 Lexington Avenue

New York, New York 10017

(212) 878–0600

(Name, Address and Telephone Number of Person
Authorized to Receive Notices and Communications)

Copy to:

Steven J. Gartner, Esq.

Robert T. Langdon, Esq.

Willkie Farr & Gallagher LLP

787 Seventh Avenue

New York, NY 10019–6099

(212) 728–8000

April 5, 2012

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. o

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See § 240.13d-7 for other parties to whom copies are to be sent.

* 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).

CUSIP No. 40963P105
SCHEDULE 13D
	1	Name of Reporting Persons Warburg Pincus Private Equity X, L.P.

	2	Check the Appropriate Box if a Member of a Group
		(a)			o
		(b)			x

	3	SEC Use Only

	4	Source of Funds N/A

	5	Check Box if Disclosure of Legal Proceeding Is Required Pursuant to Items 2(d) or 2(e) o

	6	Citizenship or Place of Organization Delaware

Number of Shares Beneficially Owned by Each Reporting Person With			7	Sole Voting Power 0

			8	Shared Voting Power 255,013,332+ (see Items 4 and 5)

			9	Sole Dispositive Power 0

			10	Shared Dispositive Power 255,013,332+ (see Item 5)

	11	Aggregate Amount Beneficially Owned by Each Person 255,013,332+ (see Item 5)

	12	Check Box if the Aggregate Amount in Row (11) Excludes Certain Shares x

	13	Percent of Class Represented by Amount in Row (11) 89.5% (see Item 5)

	14	Type of Reporting Person* PN

+Represents the number of shares of common stock, par value $0.001 (the “Common Stock”), of the Company into which the shares of the Company’s Series A-1 Convertible Preferred Stock (“Series A-1 Preferred”), the Company’s Series A-2 Convertible Preferred Stock (the “Series A-2 Preferred”) and the Series A-3 Convertible Preferred Stock (the “Series A-3 Preferred”) beneficially owned by the Reporting Person are convertible as of April 5, 2012. Giving effect to accretion in the stated value of Series A-1 Preferred, each share of Series A-1 Preferred is convertible into approximately 156 shares of Common Stock, which is determined by dividing (x) the sum of (i) the stated value of $100 per share plus (ii) the accretion thereon by (y) an effective conversion price of $0.736 per share. Giving effect to accretion in the stated value of Series A-2 Preferred, each share of Series A-2 Preferred is convertible into approximately 341 shares of Common Stock, which is determined by dividing (x) the sum of (i) the stated value of $100 per share plus (ii) the accretion thereon by (y) an effective conversion price of $0.30 per share. Each share of Series A-3 Preferred is convertible into approximately 286 shares of Common Stock, which is determined by dividing the stated value of $100 per share (without giving effect to any accretion that would accrue thereon) by a conversion price of $0.35 per share for the Series A-3 Preferred.

CUSIP No. 40963P105
SCHEDULE 13D
	1	Name of Reporting Persons Warburg Pincus X Partners, L.P.

	2	Check the Appropriate Box if a Member of a Group
		(a)			o
		(b)			x

	3	SEC Use Only

	4	Source of Funds N/A

	5	Check Box if Disclosure of Legal Proceeding Is Required Pursuant to Items 2(d) or 2(e) o

	6	Citizenship or Place of Organization Delaware

Number of Shares Beneficially Owned by Each Reporting Person With			7	Sole Voting Power 0

			8	Shared Voting Power 8,158,237+ (see Items 4 and 5)

			9	Sole Dispositive Power 0

			10	Shared Dispositive Power 8,158,237+ (see Item 5)

	11	Aggregate Amount Beneficially Owned by Each Person 8,158,237+ (see Item 5)

	12	Check Box if the Aggregate Amount in Row (11) Excludes Certain Shares x

	13	Percent of Class Represented by Amount in Row (11) 2.9% (see Item 5)

	14	Type of Reporting Person* PN

+See note on page 2.

CUSIP No. 40963P105
SCHEDULE 13D
	1	Name of Reporting Persons Warburg Pincus X, L.P.

	2	Check the Appropriate Box if a Member of a Group
		(a)			o
		(b)			x

	3	SEC Use Only

	4	Source of Funds N/A

	5	Check Box if Disclosure of Legal Proceeding Is Required Pursuant to Items 2(d) or 2(e) o

	6	Citizenship or Place of Organization Delaware

Number of Shares Beneficially Owned by Each Reporting Person With			7	Sole Voting Power 0

			8	Shared Voting Power 263,171,568+ (see Items 4 and 5)

			9	Sole Dispositive Power 0

			10	Shared Dispositive Power 263,171,568+ (see Item 5)

	11	Aggregate Amount Beneficially Owned by Each Person 263,171,568+ (see Item 5)

	12	Check Box if the Aggregate Amount in Row (11) Excludes Certain Shares x

	13	Percent of Class Represented by Amount in Row (11) 92.3% (see Item 5)

	14	Type of Reporting Person* PN

+See note on page 2.

CUSIP No. 40963P105
SCHEDULE 13D
	1	Name of Reporting Persons Warburg Pincus X LLC

	2	Check the Appropriate Box if a Member of a Group
		(a)			o
		(b)			x

	3	SEC Use Only

	4	Source of Funds N/A

	5	Check Box if Disclosure of Legal Proceeding Is Required Pursuant to Items 2(d) or 2(e) o

	6	Citizenship or Place of Organization Delaware

Number of Shares Beneficially Owned by Each Reporting Person With			7	Sole Voting Power 0

			8	Shared Voting Power 263,171,568+ (see Items 4 and 5)

			9	Sole Dispositive Power 0

			10	Shared Dispositive Power 263,171,568+ (see Item 5)

	11	Aggregate Amount Beneficially Owned by Each Person 263,171,568+ (see Item 5)

	12	Check Box if the Aggregate Amount in Row (11) Excludes Certain Shares x

	13	Percent of Class Represented by Amount in Row (11) 92.3% (see Item 5)

	14	Type of Reporting Person* OO

+See note on page 2.

CUSIP No. 40963P105
SCHEDULE 13D
	1	Name of Reporting Persons Warburg Pincus Partners LLC

	2	Check the Appropriate Box if a Member of a Group
		(a)			o
		(b)			x

	3	SEC Use Only

	4	Source of Funds N/A

	5	Check Box if Disclosure of Legal Proceeding Is Required Pursuant to Items 2(d) or 2(e) o

	6	Citizenship or Place of Organization New York

Number of Shares Beneficially Owned by Each Reporting Person With			7	Sole Voting Power 0

			8	Shared Voting Power 263,171,568+ (see Items 4 and 5)

			9	Sole Dispositive Power 0

			10	Shared Dispositive Power 263,171,568+ (see Item 5)

	11	Aggregate Amount Beneficially Owned by Each Person 263,171,568+ (see Item 5)

	12	Check Box if the Aggregate Amount in Row (11) Excludes Certain Shares x

	13	Percent of Class Represented by Amount in Row (11) 92.3% (see Item 5)

	14	Type of Reporting Person* OO

+See note on page 2.

CUSIP No. 40963P105
SCHEDULE 13D
	1	Name of Reporting Persons Warburg Pincus & Co.

	2	Check the Appropriate Box if a Member of a Group
		(a)			o
		(b)			x

	3	SEC Use Only

	4	Source of Funds N/A

	5	Check Box if Disclosure of Legal Proceeding Is Required Pursuant to Items 2(d) or 2(e) o

	6	Citizenship or Place of Organization New York

Number of Shares Beneficially Owned by Each Reporting Person With			7	Sole Voting Power 0

			8	Shared Voting Power 263,171,568+ (see Items 4 and 5)

			9	Sole Dispositive Power 0

			10	Shared Dispositive Power 263,171,568+ (see Item 5)

	11	Aggregate Amount Beneficially Owned by Each Person 263,171,568+ (see Item 5)

	12	Check Box if the Aggregate Amount in Row (11) Excludes Certain Shares x

	13	Percent of Class Represented by Amount in Row (11) 92.3% (see Item 5)

	14	Type of Reporting Person* PN

+See note on page 2.

CUSIP No. 40963P105
SCHEDULE 13D
	1	Name of Reporting Persons Warburg Pincus LLC

	2	Check the Appropriate Box if a Member of a Group
		(a)			o
		(b)			x

	3	SEC Use Only

	4	Source of Funds N/A

	5	Check Box if Disclosure of Legal Proceeding Is Required Pursuant to Items 2(d) or 2(e) o

	6	Citizenship or Place of Organization New York

Number of Shares Beneficially Owned by Each Reporting Person With			7	Sole Voting Power 0

			8	Shared Voting Power 263,171,568+ (see Items 4 and 5)

			9	Sole Dispositive Power 0

			10	Shared Dispositive Power 263,171,568+ (see Item 5)

	11	Aggregate Amount Beneficially Owned by Each Person 263,171,568+ (see Item 5)

	12	Check Box if the Aggregate Amount in Row (11) Excludes Certain Shares x

	13	Percent of Class Represented by Amount in Row (11) 92.3% (see Item 5)

	14	Type of Reporting Person* OO

+See note on page 2.

CUSIP No. 40963P105
SCHEDULE 13D
	1	Name of Reporting Persons Charles R. Kaye

	2	Check the Appropriate Box if a Member of a Group
		(a)			o
		(b)			x

	3	SEC Use Only

	4	Source of Funds N/A

	5	Check Box if Disclosure of Legal Proceeding Is Required Pursuant to Items 2(d) or 2(e) o

	6	Citizenship or Place of Organization United States of America

Number of Shares Beneficially Owned by Each Reporting Person With			7	Sole Voting Power 0

			8	Shared Voting Power 263,171,568+ (see Items 4 and 5)

			9	Sole Dispositive Power 0

			10	Shared Dispositive Power 263,171,568+ (see Item 5)

	11	Aggregate Amount Beneficially Owned by Each Person 263,171,568+ (see Item 5)

	12	Check Box if the Aggregate Amount in Row (11) Excludes Certain Shares x

	13	Percent of Class Represented by Amount in Row (11) 92.3% (see Item 5)

	14	Type of Reporting Person* IN

+See note on page 2.

CUSIP No. 40963P105
SCHEDULE 13D
	1	Name of Reporting Persons Joseph P. Landy

	2	Check the Appropriate Box if a Member of a Group
		(a)			o
		(b)			x

	3	SEC Use Only

	4	Source of Funds N/A

	5	Check Box if Disclosure of Legal Proceeding Is Required Pursuant to Items 2(d) or 2(e) o

	6	Citizenship or Place of Organization United States of America

Number of Shares Beneficially Owned by Each Reporting Person With			7	Sole Voting Power 0

			8	Shared Voting Power 263,171,568+ (see Items 4 and 5)

			9	Sole Dispositive Power 0

			10	Shared Dispositive Power 263,171,568+ (see Item 5)

	11	Aggregate Amount Beneficially Owned by Each Person 263,171,568+ (see Item 5)

	12	Check Box if the Aggregate Amount in Row (11) Excludes Certain Shares x

	13	Percent of Class Represented by Amount in Row (11) 92.3% (see Item 5)

	14	Type of Reporting Person* IN

+See note on page 2.

Pursuant to Rule 13d-2 promulgated under the Act, this Schedule 13D/A (this “Amendment No. 4”) amends the Schedule 13D filed on June 16, 2010 (the “Original Schedule 13D”) and amended on September 14, 2010 (“Amendment No. 1”), February 3, 2011 (“Amendment No. 2”) and January 10, 2012 (“Amendment No. 3” and, together with the Original Schedule 13D, Amendment No. 1, Amendment No. 2 and this Amendment No. 4, the “Schedule 13D”), and is being filed on behalf of Warburg Pincus Private Equity X, L.P., a Delaware limited partnership (“WP X”), Warburg Pincus X Partners, L.P., a Delaware limited partnership (“WPP X”, and together with WP X, the “WP X Funds”), Warburg Pincus X, L.P., a Delaware limited partnership (“WP X LP”) and the sole general partner of each of the WP X Funds, Warburg Pincus X LLC, a Delaware limited liability company (“WP X LLC”) and the sole general partner of WP X LP, Warburg Pincus Partners LLC, a New York limited liability company (“WPP LLC”) and the sole member of WP X LLC, Warburg Pincus & Co., a New York general partnership (“WP”) and the managing member of WPP LLC, Warburg Pincus LLC, a New York limited liability company (“WP LLC”) that manages each of the WP X Funds, and Messrs. Charles R. Kaye and Joseph P. Landy, each a Managing General Partner of WP and a Co-President and Managing Member of WP LLC who may be deemed to control the WP X Funds, WP X LP, WP X LLC, WPP LLC, WP and WP LLC (Mr. Kaye, Mr. Landy, WP X, WPP X, WP X LP, WP X LLC, WPP LLC, WP and WP LLC, each a “Reporting Person” and collectively being referred to as the “Warburg Pincus Reporting Persons”). This Amendment No. 4 relates to the Common Stock of Talon Therapeutics, Inc., a Delaware corporation (the “Company”). All capitalized terms used herein which are not otherwise defined herein have the same meanings given to such terms in the Original Schedule 13D, as amended.

Item 4.	Purpose of the Transaction
Item 4 of the Schedule 13D is hereby amended to include the following: On April 5, 2012, the stockholders of the Company approved an amendment to the amended and restated certificate of incorporation of the Company to increase the number of authorized shares of Common Stock. As a result, pursuant to the terms of the 2012 Investment Agreement, the number of shares of Common Stock issuable upon conversion of the Series A-3 Preferred is no longer subject to the limit set forth in the Series A-3 Certificate.

Item 5.	Interest in Securities of the Issuer
Item 5 of the Schedule 13D is hereby amended and restated in its entirety as follows: All of the computations and share amounts used herein do not give effect to any accretion on the shares of Series A-1 Preferred or Series A-2 Preferred after April 5, 2012. The percentages used herein are calculated based upon the 21,873,938 shares of Common Stock outstanding as of March 29, 2012 as reported in the Company’s Annual Report for the fiscal year ended December 31, 2011 filed by the Company with the Securities and Exchange Commission (the “SEC”) on March 29, 2012. The number of shares of Common Stock that may be deemed to be beneficially owned by the Warburg Pincus Reporting Persons, and the percentage of the outstanding shares represented thereby, in each case as reported in this Schedule 13D, are based on the number of shares of Common Stock issuable to the Warburg Pincus Reporting Persons upon conversion of the shares of Series A-1 Preferred and Series A-2 Preferred owned by the Warburg Pincus Reporting Persons on April 5, 2012 and the number of shares of Common Stock issuable to the Warburg Pincus Reporting Persons upon conversion of the 600,000 shares of Series A-3 Preferred which the WP X Funds have the right to acquire pursuant to the 2012 Investment Agreement (without giving effect to the right of the Deerfield Purchasers to purchase ten percent (10%) of such shares of Series A-3 Preferred, which exercise would reduce the number of shares acquirable by the WP X Fund). (a) WP X is the direct beneficial owner of 359,797 shares of Series A-1 Preferred, 95,931 shares of Series A-2 Preferred and 581,400 shares of Series A-3 Preferred. As of April 5, 2012, such shares are, in the aggregate, convertible into 255,013,332 shares of Common Stock (assuming such shares of Series A-3 Preferred are issued), representing approximately 89.5% of the outstanding shares of Common Stock. WPP X is the direct beneficial owner of 11,510 shares of Series A-1 Preferred, 3,069 shares of Series A-2 Preferred and 18,600 shares of Series A-3 Preferred. As of April 5, 2012, such shares are, in the aggregate,

convertible into 8,158,237 shares of Common Stock (assuming such shares of Series A-3 Preferred are issued), representing approximately 2.9% of the outstanding shares of Common Stock.

Due to their respective relationships with the WP X Funds and each other, as of April 5, 2012, each of the Warburg Pincus Reporting Persons may be deemed to beneficially own shares of Common Stock by virtue of their beneficial ownership of shares of Series A-1 Preferred, Series A-2 Preferred and Series A-3 Preferred. Assuming the full conversion of the Series A-1 Preferred in accordance with the terms of the Series A-1 Certificate, the full conversion of the Series A-2 Preferred in accordance with the terms of the Series A-2 Certificate, and the full conversion of the Series A-3 Preferred in accordance with the terms of the Series A-3 Certificate, the Warburg Pincus Reporting Persons may be deemed to beneficially own 263,171,568 shares of Common Stock, representing approximately 92.3% of the outstanding class of Common Stock, based on a total of 285,045,506 shares of Common Stock, which is comprised of: (i) the 21,873,938 shares of Common Stock outstanding referenced above, (ii) the 58,028,072 shares of Common Stock issuable to WP X and WPP X upon the conversion of shares of Series A-1 Preferred described above, (iii) the 33,714,925 shares of Common Stock issuable to WP X and WPP X upon the conversion of shares of Series A-2 Preferred described above and (iv) 171,428,571 shares of Common Stock issuable to WP X and WPP X upon the conversion of shares of Series A-3 Preferred which the WP X Funds have the right to acquire pursuant to the 2012 Investment Agreement (without giving effect to the right of the Deerfield Purchasers to purchase ten percent (10%) of such shares of Series A-3 Preferred, which exercise would reduce the number of shares acquirable by the WP X Fund).

(b) Each of WP X, WPP X, WP X LP, WP X LLC, WPP LLC, WP LLC and WP may be deemed to share with the WP X Funds the power to (i) dispose or to direct the disposition and (ii) vote or direct the vote of the 263,171,568 shares of Common Stock the WP X Funds may be deemed to beneficially own (and convert into) as of April 5, 2012.

Charles R. Kaye and Joseph P. Landy are Managing General Partners of WP and Managing Members and Co-Presidents of WP LLC and may be deemed to control the other Warburg Pincus Reporting Persons. Messrs. Kaye and Landy disclaim beneficial ownership of all shares held by the WP X Funds. Neither the filing of this Schedule 13D nor any of its contents shall be deemed to constitute an admission that any Reporting Person or any of its affiliates is the beneficial owner of any shares of Common Stock for purposes of Section 13(d) of the Exchange Act, as amended, or for any other purpose.

(c) As reported in the SEC Forms 4, each filed on February 22, 2012, by Cecilia Gonzalo and Jonathan S. Leff, directors of the Company, on February 17, 2012, (i) Ms. Gonzalo acquired (x) options to purchase 50,000 shares of Common Stock at an exercise price of $0.905 (which shares vest in three equal annual installments beginning December 14, 2012) and (y) options to purchase 35,000 shares of Common Stock at an exercise price of $0.905 (exercisable on February 17, 2013) and (ii) Mr. Leff acquired options to purchase 35,000 shares of Common Stock at an exercise price of $0.905.

Other than as set forth in this Amendment No. 4, during the last sixty (60) days there were no transactions in the Common Stock effected by the Warburg Pincus Reporting Persons, nor, to the best of their knowledge, by any of their directors, executive officers, general partners or members.

(d) Not applicable.

(e) Not applicable.

SIGNATURES

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

Dated: April 10, 2012	WARBURG PINCUS PRIVATE EQUITY X, L.P.

	By:	Warburg Pincus X, L.P., its general partner
	By:	Warburg Pincus X LLC, its general partner
	By:	Warburg Pincus Partners LLC, its sole member
	By:	Warburg Pincus & Co., its managing member


	By:	/s/ Scott A. Arenare
		Name: Scott A. Arenare
		Title: Partner


Dated: April 10, 2012	WARBURG PINCUS X PARTNERS, L.P.

	By:	Warburg Pincus X, L.P., its general partner
	By:	Warburg Pincus X LLC, its general partner
	By:	Warburg Pincus Partners LLC, its sole member
	By:	Warburg Pincus & Co., its managing member


	By:	/s/ Scott A. Arenare
		Name: Scott A. Arenare
		Title: Partner


Dated: April 10, 2012	WARBURG PINCUS X, L.P.

	By:	Warburg Pincus X LLC, its general partner
	By:	Warburg Pincus Partners LLC, its sole member
	By:	Warburg Pincus & Co., its managing member


	By:	/s/ Scott A. Arenare
		Name: Scott A. Arenare
		Title: Partner


Dated: April 10, 2012	WARBURG PINCUS X LLC

	By:	Warburg Pincus Partners LLC, its sole member
	By:	Warburg Pincus & Co., its managing member


	By:	/s/ Scott A. Arenare
		Name: Scott A. Arenare
		Title: Partner

Dated: April 10, 2012	WARBURG PINCUS PARTNERS LLC

	By:	Warburg Pincus & Co., its managing member


	By:	/s/ Scott A. Arenare
		Name: Scott A. Arenare
		Title: Partner


Dated: April 10, 2012	WARBURG PINCUS & CO.


	By:	/s/ Scott A. Arenare
		Name: Scott A. Arenare
		Title: Partner


Dated: April 10, 2012	WARBURG PINCUS LLC


	By:	/s/ Scott A. Arenare
		Name: Scott A. Arenare
		Title: Managing Director


Dated: April 10, 2012	CHARLES R. KAYE


	By:	/s/ Scott A. Arenare
		Scott A. Arenare, Attorney-in-fact*


Dated: April 10, 2012	JOSEPH P. LANDY


	By:	/s/ Scott A. Arenare
		Scott A. Arenare, Attorney-in-fact**

*	Power of Attorney given by Mr. Kaye was previously filed with the U.S. Securities & Exchange Commission (“SEC”) on March 2, 2006, as an exhibit to a Schedule 13D filed by Building Products, LLC with respect to Builders FirstSource, Inc.

**	Power of Attorney given by Mr. Landy was previously filed with the SEC on March 2, 2006, as an exhibit to a Schedule 13D filed by Building Products, LLC with respect to Builders FirstSource, Inc.