Exhibit 10.43

AMENDMENT NO. 7 TO LICENSE & OPTION AGREEMENT

THIS AMENDMENT NO. 7 TO THE LICENSE & OPTION AGREEMENT (“Amendment No. 7”) is
made and entered into this 27th day of December, 2006 (the “Amendment No. 7
Effective Date”) by and between Oscient Pharmaceuticals Corporation (“OSCIENT”),
a Massachusetts corporation, having a principal place of business at 1000 Winter
Street, Suite 2200, Waltham, Massachusetts 02451, and LG Life Sciences, LTD
(“LGLS”), a corporation organized under the laws of the Republic of Korea,
having a principal place of business at LG Twin Tower, 20 yoido-dong,
Youngdungpo-gu, Seoul, 150-721, Republic of Korea. LGLS and OSCIENT may be
referred to herein individually as a “Party” and collectively as the “Parties”.

W I T N E S S E T H

WHEREAS, LGLS and GeneSoft Pharmaceuticals, Inc. entered into a certain License
and Option Agreement dated October 22, 2002 and amended said License and Option
Agreement by Amendment No. 1 dated November 21, 2002, Amendment No. 2 dated
December 6, 2002, Amendment No. 3 dated October 16, 2003, Amendment No. 4 dated
March 31, 2005, Amendment No. 5 dated February 3, 2006, and Amendment No. 6
dated February 3, 2006 (as amended, the “License”);

WHEREAS, Genesoft merged into Genesoft Pharmaceuticals, LLC (then Guardian
Holdings, LLC (“Guardian”)) on February 6, 2004 and the benefits of and
obligations under the License were assigned to Guardian, and then, Guardian
assigned all of its right, title and interest in, to and under the License to
OSCIENT;

WHEREAS, OSCIENT is about to enter into a Partnership agreement with Menarini
(as defined below) for Menarini’s marketing of the Product in the European
Territory (as defined below) immediately after the execution of this Amendment
No. 7 based on and in accordance with the License; and the Parties desire to
amend the License to, among other things, provide certain terms and conditions
necessary for such Partnership deal between OSCIENT and Menarini and amend the
supply price, royalty rate and milestones related to sales of the Product; and

WHEREAS, the terms used herein with capital initial letters and not otherwise
defined shall have the same meanings as set forth in the License.

NOW THEREFORE, in consideration of the premises, and other good and valuable
consideration, the sufficiency of which is hereby acknowledged, the Parties
agree as follows:

 

1. Section 1.36 shall be deleted in its entirety and replaced with the
following:

1.36 “Territory” means the United States of America, Canada, Mexico, France,
Germany, the United Kingdom, Luxembourg, Ireland, Italy, Spain, Portugal,
Belgium, the Netherlands, Austria, Greece, Sweden, Denmark, Finland, Norway,
Iceland, Switzerland, Andorra, Monaco, San Marino, Vatican City, Poland, Czech
Republic, Slovakia, Slovenia, Hungary, Estonia, Latvia, Lithuania,
Liechtenstein, Malta, Cyprus, Romania, Bulgaria, Croatia, Serbia and Montenegro,
Bosnia and Herzegovina, Albania and the Former Yugoslav Republic of Macedonia.

 

2. A new Section 1.46 shall be inserted to define “Centralized Procedure” as
follows:

1.46 “Centralized Procedure” shall mean the centralized procedure for obtaining
a Marketing Authorization in the European Union as set forth in Regulation (EC)
726/2004.

 

3. A new Section 1.47 shall be inserted to define “European Territory” as
follows:

 

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

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1.47 “European Territory” means France, Germany, the United Kingdom, Luxembourg,
Ireland, Italy, Spain, Portugal, Belgium, the Netherlands, Austria, Greece,
Sweden, Denmark, Finland, Norway, Iceland, Switzerland, Andorra, Monaco, San
Marino, Vatican City, Poland, Czech Republic, Slovakia, Slovenia, Hungary,
Estonia, Latvia, Lithuania, Liechtenstein, Malta, Cyprus, Romania, Bulgaria,
Croatia, Serbia and Montenegro, Bosnia and Herzegovina, Albania and the Former
Yugoslav Republic of Macedonia.

 

4. A new Section 1.48 shall be inserted to define “Major Countries” as follows:

1.48 “Major Countries” shall mean each of France, Germany, Italy, Spain and the
United Kingdom.

 

5. A new Section 1.49 shall be inserted to define “Marketing Authorization” as
follows:

1.49 “Marketing Authorization” shall mean an authorization issued by the
European Medicines Agency, or any other national, regional, state or local
regulatory agency in the European Territory with the relevant regulatory
authority, necessary to market and sell the Product in the European Territory or
in any country in the European Territory.

 

6. A new Section 1.50 shall be inserted to define “Menarini” as follows:

1.50 “Menarini” means Menarini International Operations Luxembourg SA at Avenue
de la Gare, 1, L-1611 Luxembourg GD and any of its Affiliates.

 

7. Section 2.5 shall be deleted in its entirety and replaced with the following:

2.5 Costs of Development. All Development expenses shall be borne by OSCIENT;
provided that, LGLS shall reimburse OSCIENT for 50% of all amounts paid to
Menarini by OSCIENT for all reasonable and verifiable regulatory development
expenses incurred by Menarini in the European Territory; provided that in no
event such reimbursement payments by LGLS shall exceed $[*] in the aggregate.
With respect to any such regulatory development expenses to be reimbursed by
LGLS, OSCIENT shall provide LGLS with a copy of the statement prepared by
Menarini setting forth in detail such development expenses incurred by Menarini
in the relevant quarter and proof of payment of such expenses by OSCIENT, such
as receipt or payment slip. LGLS shall reimburse OSCIENT as provided for in this
Section 2.5 within thirty (30) days of its receipt of all such statements and
proofs. OSCIENT shall cause Menarini to keep complete and accurate books and
financial records pertaining to such costs and expenses of regulatory
development. LGLS shall have the right, at its discretion, to annually audit all
such books and records of OSCIENT and Menarini upon advance notice to OSCIENT,
and OSCIENT shall duly cooperate with LGLS. OSCIENT shall also cause Menarini to
duly cooperate with LGLS with respect to such audit.

 

8. A new Section 4.3(d)(iii) shall be inserted as follows:

4.3 Co-Promotion.

(d)(iii) Upon Oscient entering into a Partnership in the European Territory with
Menarini, LGLS’ option under subsection 4.3(a) above with respect to the
European Territory shall terminate and no longer be exercisable.

 

9. Section 5.1(a)(ii) shall be deleted in its entirety and replaced with the
following:

 

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

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5.1 General.

(a) (ii) Following the expiration or termination of the Initial Period and until
the expiration or termination of the License (the “Remaining Period”), LGLS
shall supply to OSCIENT, and OSCIENT shall exclusively purchase from LGLS, all
of OSCIENT’s requirements of API; provided that OSCIENT’s obligation to
exclusively purchase API to be supplied in Mexico, Canada or the European
Territory shall expire on the last to expire of the LGLS Patents and GLAXO
Patents claiming or covering such Product in Mexico, Canada or the European
Territory, as the case may be. Notwithstanding anything herein to the contrary,
OSCIENT agrees that it shall exclusively purchase from LGLS all its requirements
of API for Mexico, Canada, and/or the European Territory, as the case may be, so
long as and to the extent that OSCIENT continues to supply API or Final Product
in Mexico, Canada or the European Territory irrespective of any expiry of LGLS
Patents and GLAXO Patents.

LGLS shall not sell and shall procure that its Affiliates, sublicensees and
distributors shall not sell, Final Product or API to any Third Party for use or
resale in the European Territory so long as and to the extent that OSCIENT
exclusively purchases from LGLS all its requirements of API and OSCIENT’s
sublicensees and distributors exclusively purchases from OSCIENT all their
requirements of API.

 

10. A new Section 5.2(iv) shall be inserted as follows:

5.2 Supply Price.

(iv) Notwithstanding anything to the contrary in Section 5.2(iii), the API
supply price to OSCIENT for use by Menarini or its Affiliates or subcontractors
in Finished Product marketed, sold and distributed in the European Territory
shall be $[*] per kg irrespective of the volume of API purchased by OSCIENT
after the grant of Marketing Authorization in at least one country in the
European Territory is obtained. Prior to obtaining the Marketing Authorization
in at least one country in the European Territory, the API supply price to
OSCIENT for use by Menarini or its Affiliates shall be (A) prior to January 1,
2008, the same as the supply price to OSCIENT for the US, and (B) on or after
January 1, 2008, $[*] per kg up to an aggregate of [*] kg with any additional
amounts to be purchased at the then current supply price to OSCIENT for the US.

 

11. A new Section 5.6.4 (i) shall be inserted as follows:

(i) OSCIENT acknowledges and agrees that all API for use by Menarini shall be
manufactured by LGLS. OSCIENT shall ensure that all such API shall be delivered
to Menarini directly. OSCIENT shall forward to LGLS all purchase orders for API
placed by Menarini at least 90 days prior to the date upon which LGLS is
requested to ship such API. OSCIENT shall use best efforts to ensure that all
API delivered to Menarini shall be used in the European Territory only and that
such API shall not be shipped, distributed or otherwise be used in any way
whatsoever and howsoever outside the European Territory.

 

12. Section 10.2 shall be deleted in its entirety and replaced with the
following:

10.2 Milestone Payments.

(i) Following the achievement of each milestone set forth below, OSCIENT shall
owe a non-refundable milestone payment to LGLS in the amount and at the times
set forth below. Each milestone payment shall be due only once, notwithstanding
the number of Products actually

 

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

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developed or commercialized by OSCIENT hereunder. Milestone Payments 1, 2 and 3,
when earned by LGLS, shall be payable in two installments, the first of which
shall be payable on the first day of July or the first day of January (which
comes first following the date on which the milestone was earned) and the second
installment due six months thereafter. All other milestone payments shall be due
30 days after the relevant milestone event unless otherwise indicated.

 

Milestone Event

   Payment 1. Upon annual Net Sales in the United States reaching $[*] million.
   $[*] million 2. Upon both: (i) approval for the first Additional Indication
or approval of an IV formulation of the Product, and (ii) annual Net Sales in
the Territory reaching $[*] million.    $[*] million 3. Upon both: (i) approval
for a second Additional Indication or approval of an IV formulation of the
Product, and (ii) annual Net Sales in the Territory reaching $[*] million.   
$[*] million 4. Upon approval of the Product in Canada, except for any
indication approved prior to the Amendment # 5 Effective Date.    $[*]

As used in this Section 10.2, “IV formulation” shall mean a formulation of
Product for intravenous administration.

(ii) Within thirty (30) days after receipt of any and all signing or license
fees, milestone payments or royalties or any other forms of payments from
Menarini or within sixty (60) days following the achievement of such events
pursuant the terms of a Partnership agreement with Menarini (excluding, for the
avoidance of doubt, any payment with respect to the supply of API), whichever is
sooner, OSCIENT shall owe and pay a non-refundable payment to LGLS in an amount
equal to [*] percent ([*]%) of all such payments made by Menarini to OSCIENT
(except for the signing fee of $[*], the milestone payments of $[*]M related to
the receipt of the Marketing Authorization and $[*]M related to the achievement
of annual sales revenues exceeding $100M, which will be paid separately in
accordance with the payment scheme set forth below in this Section 10.2(ii)).
Attached hereto as Exhibit 10.2(ii) is the entire portion of the finally
executed Partnership agreement between OSCIENT and Menarini covering all the
signing and license fees, milestone payments and royalties and all other forms
of payments and other payment terms of the Partnership agreement by and between
OSCIENT and Menarini.

Subject to the preceding paragraph, within thirty (30) days after receipt of the
related payment or within sixty (60) days following the achievement of the
following events pursuant the terms of a Partnership agreement with Menarini,
whichever is sooner, OSCIENT shall pay LGLS:

 

[*]

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

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  (a) a non-refundable upfront signing fee payment of $[*] upon the signing of a
Partnership agreement with Menarini with respect to the European Territory; and

 

  (b) a non-refundable milestone payment of $[*]:

i. in lump sum for obtaining the Marketing Authorization for the Product via the
Centralized Procedure; or

ii. according to the following schedule in case the Marketing Authorization is
obtained on a country-by-country basis (not by Centralized Procedure) in the
Major Countries:

 

Milestone

   Payment

Upon obtaining the Marketing Authorization in the United Kingdom

   $[*]

Upon obtaining the Marketing Authorization in France

   $[*]

Upon obtaining the Marketing Authorization in Germany

   $[*]

Upon obtaining the Marketing Authorization in Italy

   $[*]

Upon obtaining the Marketing Authorization in Spain

   $[*]

in the event Menarini is able to obtain in at least one country in the Major
Countries the Marketing Authorization meeting the minimum label requirement set
forth in the Partnership agreement between Menarini and OSCIENT (which the
entire portion of the finally executed Partnership agreement between OSCIENT and
Menarini covering such minimum label requirement shall be attached hereto under
Exhibit 10.2(ii)); provided that, the foregoing provision shall not apply and
LGLS shall be entitled to the milestone(s) payment of up to $[*] in accordance
with this Section 10.2(ii)(b) if OSCIENT receives any milestone payments from
Menarini related to the grant of the Marketing Authorization whether or not
Menarini obtains in at least one country in the Major Countries the Marketing
Authorization for CAP and either AECB or ABS, and an approved label for the
Product with the minimum criteria set forth in the Partnership agreement as
stated in subsections (I) and (II) herein; and

 

  (c) a one-time, non-refundable milestone payment of $[*] in lump sum if
Marketing Authorization is obtained in all Major Countries, upon the first
achievement of Net Sales exceeding $100 million in (i) the twelve month period
following the first commercial sale of the Product in any country in the
European Territory or (ii) each successive twelve month period thereafter.

 

13. Section 10.3 shall deleted in its entirety and replaced with the following:

10.3 Royalty Payments. In addition to the foregoing license fee and milestone
payments, commencing on the second anniversary of the first commercial sale of
the Product in the United States of America,

 

[*]

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

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(i) OSCIENT shall, subject to Sections 4.3 and 10.4, pay to LGLS royalties on
Net Sales in the Territory, except for (a) any Net Sales in Mexico if OSCIENT
enters into a Partnership in Mexico with a Third Party, (b) any Net Sales in
Canada if OSCIENT enters into a Partnership in Canada with a Third Party, and
(c) any Net Sales in the European Territory if OSCIENT enters into a Partnership
in the European Territory with Menarini, for each calendar year at the following
rates:

 

Annual Net Sales

   Royalty
Rate

On the first $[*] million

   [*] percent

Over $[*] million to $[*] million

   [*] percent

Over $[*] million to $[*] million

   [*] percent

Over $[*] million to $[*] million

   [*] percent

Over $[*] million

   [*] percent

(ii) OSCIENT shall, subject to Sections 4.3 and 10.4 and in lieu of the royalty
obligations set forth in Section 10.3(i) above with respect to Net Sales in
Mexico, Canada and the European Territory, pay to LGLS (a) a royalty of [*]% on
Net Sales in Mexico for each calendar year; (b) a royalty of [*]% on Net Sales
in Canada for each calendar year; and (c) a royalty of [*]% on Net Sales in the
European Territory for each calendar year; provided, however, that if the
Partnership entered into in Mexico or Canada or the Partnership entered into
with Menarini in the European Territory, as the case may be, terminates, then
from and after such termination the royalties payable in respect of Net Sales in
Mexico, Canada or the European Territory, as the case may be, shall be paid in
accordance with clause (i) of this Section 10.3.

The Parties acknowledge that LGLS has incurred a royalty obligation to GLAXO at
a rate of [*] percent of Net Sales for the use of the GLAXO Patents, the GLAXO
Know-how and the Trademarks (the “GLAXO Royalty”). OSCIENT shall pay royalties
to LGLS at the royalty rates set forth above, and LGLS shall be solely
responsible for payment of the GLAXO Royalty and shall indemnify OSCIENT and
hold OSCIENT harmless from and against any claims by GLAXO as a result of such
use by OSCIENT of the GLAXO Patents.

 

14. Section 10.4 shall be deleted in its entirety and replaced with the
following:

10.4 Term of Royalty Obligations. OSCIENT’s obligation to make royalty payments
pursuant to 10.3 shall commence as provided in Section 10.3 and shall continue
until the later of: (i) the expiration of the last to expire of the LGLS Patents
and GLAXO Patents claiming or covering such Product in such country, and (ii) 10
years after first commercial sale of such Product in such country; provided
however, that, OSCIENT’s obligation to make royalty payments pursuant to 10.3
for Net Sales in Mexico, Canada or the European Territory shall continue until
the later of: (I) the expiration of the last to expire of the LGLS Patents and
GLAXO Patents claiming or covering such Product in Mexico, Canada or the
European Territory, as the case may be, and (II) the period of data exclusivity
in Mexico, Canada or the European Territory, as the case may be (provided that,
for purposes of clarification, “data exclusivity” in the European Territory
shall mean the period of data and market exclusivity for the Product in the
European Territory provided by Directive 2001/83/EC). Following the expiration
of OSCIENT’s royalty obligations, OSCIENT shall retain a non-exclusive,
royalty-free right to use, sell and offer for sale Product in the Territory,
using LGLS Know-how and GLAXO Know-how licensed to OSCIENT as of the Effective
Date and the exclusive right to use the Trademarks for such purposes. OSCIENT
shall continue to pay LGLS a royalty in return for such right to use the
Trademark, as provided in Section 11.4 below.

 

15. A new Section 10.8(c) shall be inserted as follows:

 

[*]

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

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(c) OSCIENT shall keep, and shall require its Affiliates to keep, complete and
accurate records of the latest three (3) years of API shipped and/or supplied to
Menarini for sale of Product in the European Territory. For the purpose of
verifying such shipments with regard to OSCIENT’s payment obligations pursuant
to Section 5.2(iv) above, LGLS shall have the right annually, at LGLS’s expense,
to retain an independent certified public accountant selected by LGLS and
reasonably acceptable to OSCIENT, to review such records in the locations(s)
where such records are maintained by OSCIENT and its Affiliates upon reasonable
notice and during regular business hours and under obligations of confidence.
Results of such review shall be made available to both LGLS and OSCIENT.

16. Section 11.4 shall be deleted in its entirety and replaced with the
following:

Expiration of the Agreement. Following the expiration of OSCIENT’s royalty
obligations as provided in Section 10.4 above, and for so long as OSCIENT
continues to use the Trademark in the use or sale of the Product, OSCIENT shall
pay to LGLS a royalty equal to [*] percent of Net Sales; provided that, for use
of the Trademark in the European Territory after the expiration of OSCIENT’s
royalty obligations in the European Territory, OSCIENT shall pay to LGLS a
royalty equal to [*]% percent of Net Sales in the European Territory (the
“Minimum Royalty Amount”) plus [*]% of any amount in excess of the Minimum
Royalty Amount paid by Menarini to OSCIENT for use of the Trademark following
the expiration of OSCIENT’s royalty obligations in the European Territory.

17. Following termination of the License, any sublicense granted by OSCIENT
under the LGLS Patents, LGLS Know-How, GLAXO Patents and GLAXO Know-How
(including pursuant to any Partnership) shall terminate. Following termination
of this Amendment No. 7, any sublicense granted by OSCIENT under the LGLS
Patents, LGLS Know-How, GLAXO Patents and GLAXO Know-How (including pursuant to
any Partnership) for the European Territory shall terminate.

18. OSCIENT represents and warrants that (i) the summary of financial terms set
forth in Schedule 18 attached hereto represent an accurate description of all of
the financial terms of the Partnership agreement between OSCIENT and Menarini;
and (ii) its Partnership agreement with Menarini shall not in any way adversely
affect or contravene with the terms and conditions of the License and this
Amendment No. 7 or the rights and obligations of LGLS thereof.

Without limiting the foregoing, OSCIENT agrees to provide LGLS the entire
portion of the finally executed Partnership agreement with Menarini covering the
financial terms and the minimum label criteria as set forth in Section 10.2
above within five (5) days from the Amendment No. 7 Effective Date, which such
part of the finally executed Partnership agreement shall be attached hereto as
Exhibit 10.2(ii) immediately thereafter within such five-day period.

19. This Amendment No. 7 shall automatically become null and void and of no
force and effect after ninety (90) days of the Amendment No. 7 Effective Date,
unless (i) OSCIENT enters into a Partnership agreement with Menarini during such
90-day period, or (b) the Parties mutually agree to extend such 90-day period.

20. OSCIENT shall timely inform and update LGLS in writing of the process and
activities related to obtaining the Marketing Authorization by Menarini. OSCIENT
shall also timely inform and update LGLS of any material changes or revisions to
the Partnership agreement between

 

[*]

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

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OSCIENT and Menarini, including but not limited to the financial terms or
termination thereof. LGLS may terminate this Amendment No. 7 upon notice at its
sole discretion in case (i) Menarini fails to obtain the complete Marketing
Authorization in at least one country in the European Territory within three
years from the effective date of the Partnership agreement between OSCIENT and
Menarini and/or (ii) the Partnership agreement between OSCIENT and Menarini is
terminated.

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

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IN WITNESS WHEREOF, the Parties have caused this Amendment No. 7 to be executed
by their duly authorized officers on the Amendment No. 7 Effective Date.

 

OSCIENT PHARMACEUTICALS CORPORATION     LG LIFE SCIENCES, LTD. By:          By:
     Name:   Steven M. Rauscher     Name:   In-Chull Kim, Ph.D. Title:   Chief
Executive Officer & President     Title:   Chief Executive Officer & President
Date:       Date:  

 

[*]

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

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Schedule 10(ii)

[*]

 

[*]

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

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Schedule 18

[*]

 

[*]

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