Unassociated Document

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

SCHEDULE 13G

(Rule 13d-102)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO RULES 13d-1(b)(c), AND (d) AND AMENDMENTS THERETO FILED

PURSUANT TO RULE 13d-2(b)

(Amendment No. ) *

Tengion, Inc.

(Name of Issuer)

Common Stock, par value $0.001 per share

(Title of Class of Securities)

88034G109

(CUSIP Number)

March 1, 2011

(Date of Event Which Requires Filing of this Statement)

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

¨ Rule 13d-1(b)

x Rule 13d-1(c)

¨ Rule 13d-1(d)

(Page 1 of 11 Pages)

_____________

* 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 the disclosures provided in a prior cover page.

The information required in 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 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.

88034G109

13G

Page 2 of 11

1.	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY) Deerfield Capital, L.P.
2.	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*		(a) o (b) ý
3.	SEC USE ONLY
4.	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5.	SOLE VOTING POWER 0
	6.	SHARED VOTING POWER 826,854(1)
	7.	SOLE DISPOSITIVE VOTING POWER 0
	8.	SHARED DISPOSITIVE VOTING POWER 826,854(1)
9.	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 826,854(1)
10.	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*		¨
11.	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 3.47%
12.	TYPE OF REPORTING PERSON* PN

(1) Comprised of 413,427 shares of common stock and 413,427 shares of common stock underlying warrants held by Deerfield Special Situations Fund, L.P.

CUSIP No.

88034G109

13G

Page 3 of 11

1.	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY) Deerfield Special Situations Fund, L.P.
2.	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*		(a) o (b) ý
3.	SEC USE ONLY
4.	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5.	SOLE VOTING POWER 0
	6.	SHARED VOTING POWER 826,854(2)
	7.	SOLE DISPOSITIVE VOTING POWER 0
	8.	SHARED DISPOSITIVE VOTING POWER 826,854(2)
9.	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 826,854(2)
10.	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*		¨
11.	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 3.47%
12.	TYPE OF REPORTING PERSON* PN

(2) Comprised of 413,427 shares of common stock and 413,427 shares of common stock underlying warrants.

CUSIP No.

88034G109

13G

Page 4 of 11

1.	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY) Deerfield Management Company, L.P.
2.	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*		(a) o (b) ý
3.	SEC USE ONLY
4.	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5.	SOLE VOTING POWER 0
	6.	SHARED VOTING POWER 1,293,286(3)
	7.	SOLE DISPOSITIVE VOTING POWER 0
	8.	SHARED DISPOSITIVE VOTING POWER 1,293,286(3)
9.	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,293,286(3)
10.	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*		¨
11.	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 5.37%
12.	TYPE OF REPORTING PERSON* PN

(3) Comprised of 646,643 shares of common stock and 646,643 shares of common stock underlying warrants held by Deerfield Special Situations Fund International Limited.

CUSIP No.

88034G109

13G

Page 5 of 11

1.	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY) Deerfield Special Situations Fund International Limited
2.	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*		(a) o (b) ý
3.	SEC USE ONLY
4.	CITIZENSHIP OR PLACE OF ORGANIZATION British Virgin Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5.	SOLE VOTING POWER 0
	6.	SHARED VOTING POWER 1,293,286(4)
	7.	SOLE DISPOSITIVE VOTING POWER 0
	8.	SHARED DISPOSITIVE VOTING POWER 1,293,286(4)
9.	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,293,286(4)
10.	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*		¨
11.	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 5.37%
12.	TYPE OF REPORTING PERSON* CO

(4) Comprised of 646,643 shares of common stock and 646,643 shares of common stock underlying warrants.

CUSIP No.

88034G109

13G

Page 6 of 11

1.	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY) James E. Flynn
2.	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*		(a) o (b) ý
3.	SEC USE ONLY
4.	CITIZENSHIP OR PLACE OF ORGANIZATION United States
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5.	SOLE VOTING POWER 0
	6.	SHARED VOTING POWER 2,120,140(5)
	7.	SOLE DISPOSITIVE VOTING POWER 0
	8.	SHARED DISPOSITIVE VOTING POWER 2,120,140(5)
9.	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,120,140(5)
10.	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*		¨
11.	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 8.3%
12.	TYPE OF REPORTING PERSON* IN

(5) Comprised of 1,060,070 shares of common stock and 1,060,070 shares of common stock underlying warrants held by Deerfield Special Situations Fund, L.P. and Deerfield Special Situations Fund International Limited.

CUSIP No.

88034G109

Page 7 of 11

Item 1(a).		Name of Issuer:

		Tengion, Inc.

Item 1(b).		Address of Issuer's Principal Executive Offices:

		2900 Potshop Lane, Suite 100 East Norrington, PA 19403

Item 2(a).		Name of Person Filing:

		James E. Flynn, Deerfield Capital, L.P., Deerfield Special Situations Fund, L.P., Deerfield Management Company, L.P., Deerfield Special Situations Fund International Limited

Item 2(b).		Address of Principal Business Office, or if None, Residence:

		James E. Flynn, Deerfield Capital, L.P., Deerfield Special Situations Fund, L.P., Deerfield Management Company, L.P., 780 Third Avenue, 37th Floor, New York, NY 10017, Deerfield Special Situations Fund International Limited, c/o Citi Hedge Fund Services (B.V.I.) Ltd., Bison Court, Columbus Centre, P.O. Box 3460, Road Town, Tortola, D8, British Virgin Islands

Item 2(c).		Citizenship:

		Mr. Flynn - United States citizen, Deerfield Capital, L.P., Deerfield Special Situations Fund, L.P., Deerfield Management Company, L.P. - Delaware limited partnerships, Deerfield Special Situations Fund International Limited - British Virgin Islands corporation

Item 2(d).		Title of Class of Securities:

		Common Stock, par value $0.001 per share

Item 2(e).		CUSIP Number:

		88034G109

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:

(a)	o	Broker or dealer registered under Section 15 of the Exchange Act.

(b)	o	Bank as defined in Section 3(a)(6) of the Exchange Act.

(c)	o	Insurance company as defined in Section 3(a)(19) of the Exchange Act.

(d)	o	Investment company registered under Section 8 of the Investment Company Act.

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88034G109

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(e)	o	An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);

(f)	o	An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F);

(g)

A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G);


(h)		o	A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act;

(i)	o	A church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act;

(j)	o	Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

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**:

			Deerfield Capital, L.P. – 826,854 Shares Deerfield Special Situations Fund, L.P. – 826,854 Shares Deerfield Management Company, L.P. – 1,293,286 Shares Deerfield Special Situations Fund International Limited – 1,293,286 Shares James E. Flynn – 2,120,140 Shares

(b)			Percent of class**:

			Deerfield Capital, L.P. – 3.47% Deerfield Special Situations Fund, L.P. – 3.47% Deerfield Management Company, L.P. – 5.37% Deerfield Special Situations International Limited – 5.37% James E. Flynn – 8.3%

(c)	Number of shares as to which such person has**:

	(i)	Sole power to vote or to direct the vote:	All Reporting Persons - 0

	(ii)	Shared power to vote or to direct the vote	Deerfield Capital, L.P. – 826,854 Shares Deerfield Special Situations Fund, L.P. – 826,854 Shares Deerfield Management Company, L.P. – 1,293,286 Shares Deerfield Special Situations Fund International Limited – 1,293,286 Shares James E. Flynn – 2,120,140 Shares

** See footnotes to cover pages.

CUSIP No.

88034G109

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(iii)	Sole power to dispose or to direct the disposition of	All Reporting Persons - 0

(iv)	Shared power to vote or to direct the vote	Deerfield Capital, L.P. – 826,854 Shares Deerfield Special Situations Fund, L.P. – 826,854 Shares Deerfield Management Company, L.P. – 1,293,286 Shares Deerfield Special Situations Fund International Limited – 1,293,286 Shares James E. Flynn – 2,120,140 Shares

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 o.

Item 6.

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

If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than five percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required.

N/A

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.

If a parent holding company or Control person has filed this schedule, pursuant to Rule 13d-1(b)(1)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company or control person has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary.

N/A

Item 8.

Identification and Classification of Members of the Group.

If a group has filed this schedule pursuant to ss.240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to ss.240.13d-1(c) or ss.240.13d-1(d), attach an exhibit stating the identity of each member of the group.

See Exhibit B.

Item 9.

Notice of Dissolution of Group.

Notice of dissolution of a group may be furnished as an exhibit stating the date of the dissolution and that all further filings with respect to transactions in the security reported on will be filed, if required, by members of the group, in their individual capacity. See Item 5.

N/A

CUSIP No.

88034G109

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Item 10.

Certifications.

"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 such purpose or effect."

CUSIP No.

88034G109

Page 11 of 11

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.

DEERFIELD CAPITAL, L.P.

By:	J.E. Flynn Capital LLC, General Partner

By:	/s/ Darren Levine
	Darren Levine, Attorney-In-Fact

DEERFIELD SPECIAL SITUATIONS FUND, L.P.

By:	Deerfield Capital, L.P.

By:	J.E. Flynn Capital LLC, General Partner

By:	/s/ Darren Levine
	Darren Levine, Attorney-In-Fact

DEERFIELD MANAGEMENT COMPANY, L.P.

By:	Flynn Management LLC, General Partner

By:	/s/ Darren Levine
	Darren Levine, Attorney-In-Fact

DEERFIELD SPECIAL SITUATIONS FUND INTERNATIONAL LIMITED

By:	/s/ Darren Levine
	Darren Levine, Attorney-In-Fact

JAMES E. FLYNN

/s/ Darren Levine
Darren Levine, Attorney-In-Fact

Date: March 11, 2011

Exhibit List

Exhibit A. Joint Filing Agreement.

Exhibit B. Item 8 Statement.

Exhibit C. Power of Attorney (1).

(1) Previously filed as Exhibit 24 to a Form 4 with regard to Hana Biosciences, Inc. (now known as Talon Therapeutics, Inc.) filed with the Commission on June 9, 2010 by Deerfield Capital L.P.; Deerfield Management Company, L.P.; Deerfield Special Situations Fund, L.P.; Deerfield Special Situations Fund International Limited; Deerfield Private Design Fund, L.P.; Deerfield Private Design International, L.P.; and James E. Flynn.

Exhibit A

Agreement

The undersigned agree that this Schedule 13G, and all amendments thereto, relating to the Common Stock of Tengion, Inc. shall be filed on behalf of the undersigned.

DEERFIELD CAPITAL, L.P.

By:	J.E. Flynn Capital LLC, General Partner

By:	/s/ Darren Levine
	Darren Levine, Attorney-In-Fact

DEERFIELD SPECIAL SITUATIONS FUND, L.P.

By:	Deerfield Capital, L.P.

By:	J.E. Flynn Capital LLC, General Partner

By:	/s/ Darren Levine
	Darren Levine, Attorney-In-Fact

DEERFIELD MANAGEMENT COMPANY, L.P.

By:	Flynn Management LLC, General Partner

By:	/s/ Darren Levine
	Darren Levine, Attorney-In-Fact

DEERFIELD SPECIAL SITUATIONS FUND INTERNATIONAL LIMITED

By:	/s/ Darren Levine
	Darren Levine, Attorney-In-Fact

JAMES E. FLYNN

/s/ Darren Levine
Darren Levine, Attorney-In-Fact

Exhibit B

Due to the relationships between them, the reporting persons hereunder may be deemed to constitute a “group” with one another for purposes of Section 13(d)(3) of the Securities Exchange Act of 1934.