Document:

Second Amendment of Rights with respect to Events of Default and Issuance

 EXHIBIT 4.1 
 ANTIGENICS, INC. 
 Second Amendment of Rights with respect to Events of Default and Issuance of
Other Securities 
 RECITALS 
 WHEREAS, reference is made to the Senior Secured Convertible Notes issued on October 30, 2006 (together with any senior secured convertible notes issued in replacement or exchange thereof in accordance with the terms thereof and any
senior secured convertible notes issued to pay interest, the “2006 Notes” and each a “2006 Note”), by Antigenics, Inc., a Delaware corporation (the “Company”) to Ingalls & Snyder Value
Partners L.P. (“Ingalls”) and Penrith LTD (“Penrith”, and together with Ingalls, the “Investors”); 
 WHEREAS, pursuant to the Indenture, dated January 25, 2005, between the Company and HSBC Bank USA, National Association, the Company issued $50.0 million of 5.25% Convertible Senior Notes due 2025 (the
“2005 Notes”) in a private placement; 
 WHEREAS, reference is made to the Amendment of Rights with Respect to Events of
Default and Issuance of Other Securities entered into by and between the Company and Ingalls on November 11, 2008 (the “First Amendment”); 
 WHEREAS, pursuant to the First Amendment, the Company and Ingalls agreed to permit the 2005 Notes Redemption and the Replenishment Offering, subject to the terms and conditions set forth in the First Amendment,
without triggering Event of Default Rights or Anti-Dilution Rights (all terms, except First Amendment, as defined in the First Amendment); 
 WHEREAS, the Company desires, at any time and from time to time, to redeem and repurchase up to an additional $12,500,000 in aggregate principal amount of 2005 Notes, along with accrued but unpaid interest, for cash, from certain holders
thereof (the “Second 2005 Notes Redemption”); 
 WHEREAS, pursuant to Section 4(a)(ii) of the 2006 Notes, as amended by
the First Amendment, the Second 2005 Notes Redemption will constitute an Event of Default (as defined in the 2006 Notes); 
 WHEREAS,
pursuant to Section 4(b) of the 2006 Notes, as amended by the First Amendment, the Investors will have certain redemption rights upon the occurrence of the Event of Default that results from the Second 2005 Notes Redemption (the “Event
of Default Rights”); 
 WHEREAS, at any time and from time to time, the Company may issue and sell shares of Company Common Stock
(as defined in the 2006 Notes), Convertible Securities (as defined in the 2006 Notes), Options (as defined in the 2006 Notes) or any combination thereof (collectively, the “New Securities”) through a public offering or a private
placement (each a “Replenishment Offering”); 
 [**] = Portions of this exhibit have been omitted pursuant to a confidential treatment
request. An unpredicted version of this exhibit has been filed separately with the Commission. 
  

 WHEREAS, pursuant to Section 7(a) of the 2006 Notes, as amended by the First Amendment, the
Investors may have certain anti-dilutive rights upon the Company’s issuance and sale of New Securities through a Replenishment Offering (the “Anti-Dilutive Rights”) if the Replenishment Offering constitutes a Dilutive Issuance
(as defined in the 2006 Notes); 
 WHEREAS, the undersigned parties desire to permit the Second 2005 Notes Redemption subject to the terms
and conditions set forth herein without triggering the Event of Default Rights; 
 WHEREAS, the undersigned parties desire to permit each
Replenishment Offering subject to the terms and conditions set forth herein without triggering the Anti-Dilutive Rights; 
 WHEREAS, pursuant
to Section 15 of the 2006 Notes, the terms of the 2006 Notes may be changed or amended by either (i) the affirmative vote at a meeting duly called for such purpose or (ii) the written consent without a meeting, of the holders of 2006
Notes representing at least a majority of the aggregate principal amount of the 2006 Notes then outstanding; and 
 WHEREAS, Ingalls holds
2006 Notes representing 80% of the aggregate principal amount of the 2006 Notes outstanding; 
 NOW, THEREFORE, in consideration of the
promises and agreements set forth in this Second Amendment of Rights with respect to Events of Default and Issuance of Other Securities (this “Second Amendment”), the undersigned agree as follows: 
 AGREEMENT 
  

	1.	Definitions. Capitalized terms used in this Second Amendment without definition shall have the meanings ascribed to them in the 2006 Notes. 

  

	2.	Second Amendment. 

 The parties hereto hereby amend the Event of
Default Rights by excluding the Second 2005 Notes Redemption from the definition of an Event of Default in Section 4(a)(ii) of the 2006 Notes, as amended by the First Amendment, subject to the condition that, in connection with the Second 2005
Notes Redemption, redemptions or repurchases by the Company of 2005 Notes be at a purchase price that does not exceed the sum of (i) [**] of the outstanding principal of such notes plus (ii) [**]. 
 [**] = Portions of this exhibit have been omitted pursuant to a confidential treatment request. An unpredicted version of this exhibit has been filed separately
with the Commission. 

 The parties hereto hereby amend Section 7(a) of the 2006 Notes, as amended by the First Amendment, by excluding each
Replenishment Offering in connection with the Second 2005 Notes Redemption from the definition of a Dilutive Issuance, subject to the following conditions: 
  

	 	i.	The ratio in such Replenishment Offering of (x) the principal amount of the 2005 Notes redeemed and repurchased by the Company pursuant to the Second 2005 Notes Redemption and
(y) the number of New Securities issued in such Replenishment Offering exceeds [**]. 

  

	 	ii.	This section 2.b shall be deemed to modify section 2.b of the First Amendment and shall apply to up to an aggregate number of shares of Company Common Stock (a) issued and sold
through all Replenishment Offerings and (b) available for issuance under Options and/or Convertible Securities sold through all Replenishment Offerings, equal to [**] of the total number of shares of Company Common Stock issued and outstanding
on the Business Day immediately preceding the consummation of the Replenishment Offering in question. 

  

	3.	Miscellaneous. Other than as specifically set forth herein, this Second Amendment shall not be construed as a consent to any future action or an amendment of any right or
remedy on any future occasion. This Second Amendment may be executed in one or more counterparts, all of which shall be considered one and the same amendment. 

 [Signature Page Follows] 
 [**] = Portions of this exhibit have been omitted pursuant to a
confidential treatment request. An unpredicted version of this exhibit has been filed separately with the Commission. 
  

 -3- 

 IN WITNESS WHEREOF, the undersigned have executed this First Amendment as of June 3, 2009.

  

			
	ANTIGENICS, INC.
		
	By:	 	/s/ Shalini Sharp
	Name:	 	Shalini Sharp
	Title:	 	CFO
	
	INGALLS & SNYDER VALUE PARTNERS L.P.
		
	By:	 	/s/ Thomas O. Boucher
	Name:	 	Thomas O. Boucher
	Title:	 	General Partner

 [**] = Portions of this exhibit have been omitted pursuant to a confidential treatment request. An
unpredicted version of this exhibit has been filed separately with the Commission. 
  

 -4- 

 ANTIGENICS, INC. 
 Third Amendment of Rights with respect to Events of Default and Issuance of Other Securities 
 RECITALS 
 WHEREAS, reference is made to the Senior Secured Convertible Notes issued on October 30, 2006 (together with
any senior secured convertible notes issued in replacement or exchange thereof in accordance with the terms thereof and any senior secured convertible notes issued to pay interest, the “2006 Notes” and each a “2006
Note”), by Antigenics, Inc., a Delaware corporation (the “Company”) to Ingalls & Snyder Value Partners L.P. (“Ingalls”) and Penrith LTD (“Penrith”, and together with Ingalls, the
“Investors”); 
 WHEREAS, pursuant to the Indenture, dated January 25, 2005, between the Company and HSBC Bank USA,
National Association, the Company issued $50.0 million of 5.25% Convertible Senior Notes due 2025 (the “2005 Notes”) in a private placement; 
 WHEREAS, reference is made to the Amendment of Rights with Respect to Events of Default and Issuance of Other Securities entered into by and between the Company and Ingalls on November 11, 2008 (the
“First Amendment”) and the Second Amendment of Rights with Respect to Events of Default and Issuance of Other Securities entered into by and between the Company and Ingalls on June 3, 2009 (the “Second
Amendment”); 
 WHEREAS, pursuant to the First Amendment, the Company and Ingalls agreed to permit the 2005 Notes Redemption and the
Replenishment Offering, subject to the terms and conditions set forth in the First Amendment, without triggering Event of Default Rights or Anti-Dilution Rights (all terms, except First Amendment, as defined in the First Amendment); 
 WHEREAS, pursuant to the Second Amendment, the Company and Ingalls agreed to permit the Second 2005 Notes Redemption and the Replenishment Offering,
subject to the terms and conditions set forth in the Second Amendment, without triggering Event of Default Rights or Anti-Dilution Rights (all terms used as defined in the Second Amendment); 
 WHEREAS, the Company desires, at any time and from time to time, to redeem and repurchase up to an additional $10,500,000 in aggregate principal amount
of 2005 Notes, along with accrued but unpaid interest, for cash, from certain holders thereof (the “Third 2005 Notes Redemption”); 
 WHEREAS, pursuant to Section 4(a)(ii) of the 2006 Notes, as amended by the First Amendment and the Second Amendment, the Third 2005 Notes Redemption will constitute an Event of Default (as defined in the 2006 Notes); 
 [**] = Portions of this exhibit have been omitted pursuant to a confidential treatment request. An unpredicted version of this exhibit has been filed separately
with the Commission. 
  

 -5- 

 WHEREAS, pursuant to Section 4(b) of the 2006 Notes, as amended by the First Amendment and the
Second Amendment, the Investors will have certain redemption rights upon the occurrence of the Event of Default that results from the Third 2005 Notes Redemption (the “Event of Default Rights”); 
 WHEREAS, at any time and from time to time, the Company may issue and sell shares of Company Common Stock (as defined in the 2006 Notes), Convertible
Securities (as defined in the 2006 Notes), Options (as defined in the 2006 Notes) or any combination thereof (collectively, the “New Securities”) through a public offering or a private placement (each a “Replenishment
Offering”); 
 WHEREAS, pursuant to Section 7(a) of the 2006 Notes, as amended by the First Amendment and the Second Amendment,
the Investors may have certain anti-dilutive rights upon the Company’s issuance and sale of New Securities through a Replenishment Offering (the “Anti-Dilutive Rights”) if the Replenishment Offering constitutes a Dilutive
Issuance (as defined in the 2006 Notes); 
 WHEREAS, the undersigned parties desire to permit the Third 2005 Notes Redemption subject to the
terms and conditions set forth herein without triggering the Event of Default Rights; 
 WHEREAS, the undersigned parties desire to permit
each Replenishment Offering subject to the terms and conditions set forth herein without triggering the Anti-Dilutive Rights; 
 WHEREAS,
pursuant to Section 15 of the 2006 Notes, the terms of the 2006 Notes may be changed or amended by either (i) the affirmative vote at a meeting duly called for such purpose or (ii) the written consent without a meeting, of the holders
of 2006 Notes representing at least a majority of the aggregate principal amount of the 2006 Notes then outstanding; and 
 WHEREAS, Ingalls
holds 2006 Notes representing 80% of the aggregate principal amount of the 2006 Notes outstanding; 
 NOW, THEREFORE, in consideration of the
promises and agreements set forth in this Third Amendment of Rights with respect to Events of Default and Issuance of Other Securities (this “Third Amendment”), the undersigned agree as follows: 
 AGREEMENT 
  

	4.	Definitions. Capitalized terms used in this Second Amendment without definition shall have the meanings ascribed to them in the 2006 Notes. 

  

	5.	Third Amendment. 

  

	 	a.	The parties hereto hereby amend the Event of Default Rights by excluding the Third 2005 Notes Redemption from the definition of an Event of Default in 

 [**] = Portions of this exhibit have been omitted pursuant to a confidential treatment request. An unpredicted version of this exhibit has been filed separately
with the Commission. 
  

 -6- 

	 	    	Section 4(a)(ii) of the 2006 Notes, as amended by the First Amendment and the Second Amendment, subject to the condition that, in connection with the Third 2005 Notes
Redemption, redemptions or repurchases by the Company of 2005 Notes be at a purchase price that does not exceed the sum of (i) [**] of the outstanding principal of such notes plus (ii) the [**]. 

  

	 	b.	The parties hereto hereby amend Section 7(a) of the 2006 Notes, as amended by the First Amendment and the Second Amendment, by excluding each Replenishment Offering in
connection with the Third 2005 Notes Redemption from the definition of a Dilutive Issuance, subject to the following conditions: 

  

	 	i.	The ratio in such Replenishment Offering of (x) the principal amount of the 2005 Notes redeemed and repurchased by the Company pursuant to the Third 2005 Notes Redemption and
(y) the number of New Securities issued in such Replenishment Offering exceeds [**]. 

  

	 	ii.	This section 2.b shall be deemed to modify section 2.b of the First Amendment and the Second Amendment and shall apply to up to an aggregate number of shares of Company Common Stock
(a) issued and sold through all Replenishment Offerings and (b) available for issuance under Options and/or Convertible Securities sold through all Replenishment Offerings, equal to [**] of the total number of shares of Company Common
Stock issued and outstanding on the Business Day immediately preceding the consummation of the Replenishment Offering in question. 

  

	6.	Miscellaneous. Other than as specifically set forth herein, this Third Amendment shall not be construed as a consent to any future action or an amendment of any right or
remedy on any future occasion. This Third Amendment may be executed in one or more counterparts, all of which shall be considered one and the same amendment. 

 [Signature Page Follows] 
 [**] = Portions of this exhibit have been omitted pursuant to a confidential treatment
request. An unpredicted version of this exhibit has been filed separately with the Commission. 
  

 -7- 

 IN WITNESS WHEREOF, the undersigned have executed this Third Amendment as of June 4, 2009.

  

			
	ANTIGENICS, INC.
		
	By:	 	/s/ Shalini Sharp
	Name:	 	Shalini Sharp
	Title:	 	CFO
	
	INGALLS & SNYDER VALUE PARTNERS L.P.
		
	By:	 	/s/ Thomas O. Boucher
	Name:	 	Thomas O. Boucher
	Title:	 	General Partner

 [**] = Portions of this exhibit have been omitted pursuant to a confidential treatment request. An
unpredicted version of this exhibit has been filed separately with the Commission.Securities Exchange Agreement with Tang Capital Partners, LP

 EXHIBIT 10.1 
 ANTIGENICS INC. 
 SECURITIES EXCHANGE AGREEMENT 
 This Securities Exchange Agreement (this “Agreement”) is made as of June 3, 2009 (the “Effective
Date”) by and between ANTIGENICS INC., a Delaware corporation (the “Company”), and TANG CAPITAL PARTNERS, LP (the
“Bond Holder”). 
 RECITALS 
 WHEREAS, the Bond Holder wishes to exchange a aggregate of $12,442,000.00 principal amount of the Company’s
5.25% convertible senior notes due February 2025 (collectively, the “Bonds”). 
 WHEREAS, the Company wishes to issue to the Bond Holder, pursuant to the exemption from registration provided by Section 3(a)(9) (“Section 3(a)(9)”) under the Securities Act
of 1933, as amended (the “Securities Act”), 4,028,838 shares of the Company’s common stock, par value $0.01 per share (the “Common Stock”) in exchange for the Bonds (the
“Exchange”) and to cancel the Bonds upon the terms and conditions set forth herein. 
 AGREEMENT

 1. Exchange; Delivery. Bond Holder hereby assigns, sells and transfers the Bonds, plus all claims arising out of or
relating to the Bonds, including but not limited to any accrued but unpaid interest, to the Company in exchange for the issuance by the Company, effective as of the Effective Date, of 4,028,838 shares of Common Stock (the
“Shares”) to the Bond Holder (the “Exchange”). On the business day immediately following the Effective Date, the Company shall deliver the Shares to the Bond Holder via DWAC to an account specified in
writing by the Bond Holder and the Bond Holder shall deliver the Bonds to the Company via DTC to an account specified in writing by the Company. 
 2. Representations and Warranties of the Company. The Company hereby represents and warrants to the Bond Holder that as of the Effective Date: 
 2.1 Organization. The Company is duly incorporated and validly existing in good standing under the laws of the State of
Delaware. The Company has full corporate power and authority to own, operate and occupy its properties and to conduct its business as presently conducted and is registered or qualified to do business and is in good standing in each jurisdiction in
which it owns or leases property or transacts business and where the failure to be so qualified would have a material adverse effect on the Company, and, to the Company’s knowledge (as defined below), no proceeding has been instituted in any
such jurisdiction revoking, limiting or curtailing, or seeking to revoke, limit or curtail, such power and authority or qualification. 

 2.2 Due Authorization. The Company has all requisite
corporate power and authority to execute, deliver and perform its obligations under this Agreement. This Agreement has been duly authorized and validly executed and delivered by the Company and no other corporate action on the part of the Company,
its board of directors or its stockholders is necessary to authorize the execution and delivery by the Company of this Agreement or the consummation of the transactions contemplated by this Agreement, including, without limitation, the issuance and
delivery of the Shares. Furthermore, the Company’s board of directors has duly authorized the execution and delivery by the Company of this Agreement and the transactions contemplated hereunder. This Agreement, assuming due and valid
authorization, execution and delivery hereof and thereof by the Bond Holder, constitutes a legal, valid and binding agreement of the Company, enforceable against the Company in accordance with its terms, except as rights to indemnity and
contribution may be limited by state or federal securities laws, except as enforceability may be limited by applicable bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors’ and contracting parties’ rights
generally, and except as enforceability may be subject to general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law). 
 2.3 Valid Issuance; Reservation of Shares; Preemptive Rights. The Shares are duly authorized and, when issued and
exchanged in accordance with the terms hereof, (i) will be duly and validly issued, free and clear of any liens, claims, encumbrances or contractual restrictions on transfer (“Liens”) imposed by or through the Company or
by operation of law of which the Company has knowledge and (ii) will be issued and delivered in compliance with all applicable Federal and state securities laws. Neither the cancellation of the Bonds upon the Effective Date, nor the Exchange,
nor the performance by the Company of its obligations under this Agreement will trigger any preemptive, “poison-pill”, anti-takeover, anti-dilution, reset or other similar rights. 
 2.4 Non-Contravention. The execution and delivery of this Agreement, the issuance of the Shares and the
consummation of the transactions contemplated hereby and thereby will not (a) conflict with or constitute a material violation of or default (with the passage of time or otherwise) under or give rise to any right of termination, material
amendment, cancellation or acceleration or loss of any material rights under (i) any material contracts to which the Company is a party, or (ii) the certificate of incorporation or the bylaws of the Company or any similar organizational
document of the Company, or (b) (i) result in the creation or imposition (or the obligation to create or impose) of any material lien, encumbrance, claim, security interest, pledge, charge or restriction of any kind upon any of the
properties or assets of the Company or (ii) an acceleration of indebtedness pursuant to any obligation, agreement or condition contained in agreement or document to which the Company is a party or is bound other than the with respect to the
Bonds, or (c) to the Company’s knowledge, violate any order or decree applicable to the Company, or by which it or any of its operations are bound, and no such violation or default currently exists. No consent, approval, authorization or
other order of, or registration, qualification or filing with, any regulatory body, administrative agency or other governmental body in the United States is required for the execution and delivery of the Agreement and the valid issuance of the
Shares prior to the Effective Date except for any securities filings required to be made under state securities laws. 
  

 2 

 2.5 Exchange Act Compliance. The documents that the Company filed under the
Exchange Act since December 31, 2008 (including all exhibits included therein and documents incorporated by reference therein hereinafter being referred to as the “Required Documents”) complied in all
material respects with the requirements of the Exchange Act, and the rules and regulations of the Commission promulgated thereunder as of their respective filing dates, and none of the Required Documents, when filed, contained any untrue statement
of a material fact or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading. 
 2.6 Non-Public Information. The Company does not currently intend to issue any press release within the next five days that
contains any material non-public information currently known to the Company. The Bond Holder has not requested from the Company, and the Company has not furnished to the Bond Holder, any material non-public information concerning the Company.

 2.7 Exemption from Registration. The Exchange is exempt from the registration requirements of the
Securities Act pursuant to the provisions of Section 3(a)(9) thereof. The Company has complied in all material respects with such provisions and, without limiting the generality thereof, has not paid to any person, directly or indirectly, any
commission or other remuneration for soliciting the Exchange. Neither the Company nor any of its affiliates, nor any person acting on its or their behalf, (i) has engaged in any form of general solicitation or general advertising (within the
meaning of Regulation D) in connection with the Exchange, (ii) has issued any shares of Common Stock or shares of any series of preferred stock or other securities or instruments convertible into, exchangeable for or otherwise entitling the
holder thereof to acquire shares of Common Stock which would be integrated with the Exchange for purposes of the Securities Act, nor will the Company or any of its affiliates take any action or steps that would require registration of the Shares
under the Securities Act. 
 2.8 No Reliance. In entering into this Agreement, the Company (i) is
not relying on any advice or representation of the Bond Holder or any of its affiliates (other than the representations of the Bond Holder contained herein), (ii) has not received from the Bond Holder or any of its affiliates any assurance or
guarantee as to the merits (whether legal, regulatory, tax, financial or otherwise) of the Exchange or entering into this Agreement, (iii) has consulted with its own legal, regulatory, tax, business, investment, financial and accounting
advisors to the extent that it has deemed necessary, and (iv) has entered into this Agreement based on its own independent judgment and on the advice of its advisors as it has deemed necessary, and not on any view (whether written or oral)
expressed by the Bond Holder or any of its affiliates. Neither the Bond Holder nor any of its affiliates is now or has ever been a financial advisor, or other fiduciary, with respect to the Company. 
 2.9 Bankruptcy Protection. The Company has not taken any steps, and does not currently expect to take any steps, to
seek protection pursuant to 11 U.S.C. §§ 101 et seq. (the “Bankruptcy Code”) or any similar state bankruptcy law nor does the Company have any knowledge or reason to believe that its creditors intend to initiate an
involuntary proceeding under the Bankruptcy Code or any such state law. 
  

 3 

 2.10 Fair Value. To the Company’s knowledge, as of the date of this
Agreement and, based upon reasonable estimates made by the Company, after giving effect to the Exchange, the fair value of the Company’s assets will exceed the amount of its liabilities. 
 3. Representations and Warranties of the Bond Holder. The Bond Holder hereby represents and warrants to the Company as follows:

 3.1 Due Authorization. The Bond Holder has all requisite corporate power and authority to execute, deliver
and perform its obligations under this Agreement, and this Agreement has been duly authorized and validly executed and delivered by the Bond Holder and no other corporate action on the part of the Bond Holder is necessary to authorize the execution
and delivery by the Bond Holder of this Agreement. This Agreement constitutes a legal, valid and binding agreement of the Bond Holder, enforceable against the Bond Holder in accordance with its terms, except as enforceability may be limited by
applicable bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors’ and contracting parties’ rights generally, and except as enforceability may be subject to general principles of equity (regardless of
whether such enforceability is considered in a proceeding in equity or at law). 
 3.2 No Legal, Tax or Investment
Advice. The Bond Holder understands that nothing in this Agreement or any other materials presented to the Bond Holder in connection with the Exchange constitutes legal, tax or investment advice and represents and warrants to the Company that it
has consulted such legal, tax and investment advisors as it, in its sole discretion, has deemed necessary or appropriate in connection with the Exchange. 
 3.3 Affiliate Status. As of Effective Date, the Bond Holder represents and warrants that the Bond Holder is not an affiliate of the Company, and has not been an affiliate of the Company for the three
months preceding the Effective Date. 
 3.4 No Regulatory Review. The Bond Holder understands that no United
States federal or state agency has passed on, reviewed or made any recommendation or endorsement of the Shares issuable hereunder. 
 3.5 No Transactions in Company Securities. Neither the Bond Holder, directly or indirectly, nor any person acting on behalf of or pursuant to any understanding with the Bond Holder, has engaged in any transactions in the
securities of the Company (including, without limitation, any short sales involving any of the Company’s securities) since the time that Bond Holder first began discussion with the Company regarding the Exchange through and including the date
hereof. The Bond Holder covenants that neither it nor any person acting on its behalf or pursuant to any understanding with the Bond Holder will engage, directly or indirectly, in any transactions in the securities of the Company (including short
sales) prior to the time the transactions contemplated by this Agreement are first publicly disclosed. 
 4. Amendment and
Waiver. No provision of this Agreement may be amended or modified except upon the written consent of the Company and the Bond Holder, and no provision hereof may be waived other than by a written instrument signed by the party
against whom enforcement of any such waiver is sought. 
  

 4 

 5. Miscellaneous. 
 5.1 Attorneys’ Fees. In the event that any suit or action is instituted under or in relation to this
Agreement, including without limitation to enforce any provision in this Agreement, each party in such dispute shall pay all of its own fees, costs and expenses of enforcing any right of such party under or with respect to this Agreement, including
without limitation, such fees and expenses of attorneys and accountants, which shall include, without limitation, all fees, costs and expenses of appeals. 
 5.2 Headings; Construction. The headings of the various sections of this Agreement have been inserted for convenience of reference only and shall not be deemed to be part of this Agreement.
The language used in this Agreement is and will be deemed to be the language chosen by the parties to express their mutual intent, and no rules of strict construction will be applied against any party. 
 5.3 Pronouns. All pronouns contained herein, and any variations thereof, shall be deemed to refer to the masculine,
feminine or neutral, singular or plural, as to the identity of the parties hereto may require. 
 5.4
Severability. In case any provision contained in this Agreement should be invalid, illegal or unenforceable in any respect, the validity, legality and enforceability of the remaining provisions contained herein shall not in any way be
affected or impaired thereby. 
 5.5 Governing Law. This Agreement shall be governed by, and construed in
accordance with, the internal laws of the State of New York, without giving effect to the principles of conflicts of law. The parties agree that any action brought by either party under or in relation to this Agreement, including without limitation
to interpret or enforce any provision of this Agreement, shall be brought in, and each party agrees to and does hereby submit to the jurisdiction and venue of, any state or federal court located in New York. 
 5.6 Entire Agreement. This Agreement constitutes the full and entire understanding and agreement between the parties with
regard to the subjects hereof, and no party shall be liable or bound to any other in any manner by any oral or written representations, warranties, covenants and agreements except as specifically set forth herein. Each party expressly represents and
warrants that it is not relying on any oral or written representations, warranties, covenants or agreements outside of this Agreement. 
 5.7 Counterparts. This Agreement may be executed in two (2) or more counterparts, each of which shall constitute an original, but all of which, when taken together, shall constitute but one
(1) instrument, and shall become effective when one (1) or more counterparts have been signed by each party hereto and delivered to the other parties. 
 5.8 Successors and Assigns. This Agreement shall be binding upon and inure to the benefit of the parties and their
respective successors and assigns. 
  

 5 

 5.9 No Third Party Beneficiaries. This Agreement is intended for the
benefit of the parties hereto and their respective permitted successors and assignees, and is not for the benefit of, nor may any provision hereof be enforced by, any other person. 
 5.10 Further Assurances. Each party shall do and perform, or cause to be done and performed, all such further acts
and things, and shall execute and deliver all such other agreements, certificates, instruments and documents, as any other party may reasonably request in order to carry out the intent and accomplish the purposes of this Agreement and the
consummation of the transactions contemplated hereby. 
 5.11 Press Release; Form 8-K. The Company agrees
that it will, prior to 9:30 a.m. Eastern time, on the first business day after the Effective Date, either file with the Commission a Current Report on Form 8-K disclosing the material terms of this Agreement and the transactions contemplated hereby
or issue a press release disclosing the same; provided, however, that the Bond Holder shall have a reasonable opportunity to review and comment on any such Form 8-K or press release, as applicable, prior to the issuance or filing thereof and shall
not be deemed to possess material non-public information upon the filing of such Form 8-K or issuance of such press release. 
  

 6 

 IN WITNESS WHEREOF, the parties hereto have executed
this SECURITIES EXCHANGE AGREEMENT as of the date set forth in the first paragraph hereof. 
  

									
	COMPANY:	 		 	BOND HOLDERS:
			
	ANTIGENICS INC.	 		 	TANG CAPITAL PARTNERS, LP
					
	By:	 	/s/ Shalini Sharp	 		 	By:	 	/s/ Kevin Tang
	Name:	 	Shalini Sharp	 		 	Name:	 	Kevin Tang
	Title:	 	Chief Financial Officer	 		 	Title:	 	Managing Director

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