Exhibit 10.46

SECOND AMENDMENT TO LEASE AGREEMENT

           THIS SECOND AMENDMENT TO LEASE AGREEMENT (this “Amendment”) is made
as of December 13, 2010, between BRANDYWINE RESEARCH LLC, a Delaware limited
liability company (“Landlord”), and EMERGENT BIOSOLUTIONS INC., a Delaware
corporation (“Tenant”).

RECITALS

           Recital 1.                      Landlord and Tenant are parties to a
certain Lease Agreement, dated June 27, 2006, as amended by a certain First
Amendment to Lease Agreement, dated November 13, 2007 (as amended to date, the
“Lease”), under which Landlord leases to Tenant 22,872 square feet of rentable
area (the “Current Premises”) at 2273 Research Boulevard, Rockville, Maryland
(the “Building”).

           Recital 2.                      Landlord and Tenant desire to amend
the Lease to provide for the expansion of the Current Premises to include
certain additional space containing 10,428 square feet of rentable area located
on the third (3rd) floor of the Building, which space is more fully described on
Exhibit A–Floor Plan of Expansion Space attached to this Amendment (the
“Expansion Space”), and to make certain other amendments to the Lease, all as
more particularly set forth in this Amendment.

AGREEMENT

           NOW, THEREFORE, in consideration of the sum of Ten Dollars ($10.00)
and for other good and valuable consideration, the receipt and sufficiency of
which the parties hereby acknowledge, and intending to be legally bound hereby,
Landlord and Tenant agree that the Lease is amended as follows:
 
           1.           Recitals Incorporated; Definitions. The foregoing
recitals are incorporated by reference into this Section as if set forth in the
Section in full. Except as otherwise provided herein, capitalized terms used but
not defined in this Amendment shall have the meanings given such terms in the
Lease.

           2.           Lease of Expansion Space.  Landlord hereby leases the
Expansion Space to Tenant and Tenant hereby leases the Expansion Space from
Landlord for a term beginning on the Expansion Space Commencement Date
(hereinafter defined) and continuing through the Expiration Date and any
extension thereof; thus, the Lease term for the Expansion Space will be
coterminous with the Lease term for the Current Premises.

           3.           Commencement Date; Delivery of Expansion Space.

a.           “Expansion Space Commencement Date” means the later of December  1,
2010 or the date on which Landlord tenders possession of the Expansion Space to
Tenant. By a Confirmation of Lease Term (the “COLT”), Landlord shall notify
Tenant of the Expansion Space Commencement Date and all other matters stated
therein. The COLT shall be conclusive and binding on Tenant as to all matters
set forth therein, unless within twenty (20) days following delivery of the COLT
to Tenant, Tenant contests any of the matters contained therein by notifying
Landlord in writing of Tenant’s objections.

                      b.           Landlord and Tenant acknowledge that on the
date this Amendment is fully executed and delivered, the Expansion Space is
occupied by a third-party (the “Prior Occupant”), and that if the Prior Occupant
does not physically vacate and surrender the Expansion Space when lawfully
required, Landlord shall be unable to deliver the Expansion Space to Tenant on
the target date of December 1, 2010 (the “Target Date”). If Landlord does not
deliver the Expansion Space to Tenant within thirty-one (31) days after the date
on which this Amendment is fully executed and delivered (“Outside Date”), as
Tenant’s sole remedy, Tenant shall have the unqualified right to terminate this
Amendment; provided, however, in order to exercise such termination right,
Tenant shall give Landlord written notice of such termination prior to the
earlier of the Expansion Space Commencement Date or within thirty-one (31) days
after the Outside Date. In such event (and regardless of whether Tenant
exercises its termination right), Landlord shall have no liability if Landlord
does not deliver the Expansion Space to Tenant on or before the Outside Date,
provided that Landlord uses reasonable good faith efforts to deliver the
Expansion Space to Tenant as soon after the Target Date, as Landlord is
reasonably able to do so, except Landlord shall reimburse Tenant up to One
Thousand Dollars ($1,000.00) for Tenant’s reasonable architectural test fit plan
costs incurred in connection with the Expansion Space. Nothing herein contained
shall obligate Landlord to make any payment to, or commence any litigation
against, the Prior Occupant in order to entice the Prior Occupant to physically
vacate and surrender possession of the Expansion Space.

                      c.           Landlord represents and warrants to Tenant
that Landlord and the tenant who currently subleases the Expansion Space to the
Prior Occupant have executed and delivered a lease termination agreement
terminating such tenant’s right to lease the Expansion Space not later than on
the date hereof.

           4.           Fixed Rent. Tenant shall pay Fixed Rent for the
Expansion Space beginning on the Expansion Space Commencement Date, which Fixed
Rent payments Tenant shall make as and when due under the Lease and at the rate
from time to time in effect as set forth on Rider No. 1-Expansion Space Fixed
Rent, which Rider sets forth Tenant’s Fixed Rent abatement right with respect to
the Expansion Space. With respect to the Current Premises, Tenant shall continue
pay Fixed Rent at the rates from time to time in effect as set forth in the
Lease. If Tenant hereafter extends the Expiration Date pursuant to any extension
rights set forth in the Lease or otherwise by written agreement with Landlord,
Tenant shall pay Fixed Rent for the Expansion Space during the extension term at
the same rate(s) and at the same time(s) that Fixed Rent is payable for the
Current Premises during the extension term.

           5.           Expansion of Current Premises.  Beginning on the
Expansion Space Commencement Date, the following shall apply:

                      a.           the Premises shall include the Expansion
Space  (i.e., the Premises shall contain 33,300 square feet of rentable area,
being comprised of the Current Premises’ 22,872 square feet of rentable area and
the Expansion Space’s 10,428 square feet of rentable area);

                      b.           Tenant’s Allocated Share shall be 22.231%;
and

                      c.           Tenant shall be entitled to four (4) reserved
parking spaces (inclusive of the three (3) reserved parking spaces to which
Tenant is presently entitled under the Lease) in the Building’s parking garage
at no fee during the initial Term.

           6.           Condition of Expansion Space.

                      a.           Except as set forth in Section 6b, Landlord
shall have no obligation to perform any demolition work or to deliver, make or
install any materials or improvements in, to or at the Expansion Space and
Tenant shall accept the Expansion Space in “as is” condition on the Expansion
Space Commencement Date.

                      b.           Landlord, at Landlord’s expense, shall
perform the following work (collectively, “Landlord’s Work”):

                                i.           promptly after this Amendment is
fully executed and delivered, Landlord shall modify lobby space as shown on
Exhibit B-Lobby Plan and begin to refurbish the lobby space (as applicable).
Tenant shall have the right at its sole expense to upgrade lobby finishes beyond
the standard building finish, provided the upgrades do not delay the completion
of Landlord’s Work or any portion thereof and are reasonably satisfactory to
Landlord;

                                ii.           not later than on the Demising
Deadline, Landlord shall substantially complete the demising of the Expansion
Space along the I-270 side of the Expansion Space by completing the addition of
the wall to separate the two premises and the installation of dedicated front
door for the Expansion Space (the “Demising Work”). Tenant shall have the right
at its sole expense to upgrade the quality and/or security features of its front
door beyond the standard building finish, provided the upgrades do not delay the
completion of Landlord’s work or any portion thereof and are reasonably
satisfactory to Landlord. The “Demising Deadline” shall be the date that is
sixty (60) days after this Amendment is fully executed and delivered, which date
shall be extended on a day for day basis for each day that Landlord is delayed
in substantially completing the Demising Work due to any delay caused by Tenant
and/or by reason of labor disputes, war, terrorism, civil unrest, inclement
weather, fire or other casualty, accidents, orders or regulations of any
governmental authority, governmental delays or any other cause beyond the
reasonable control of Landlord (a “Force Majeure Delay”); and

iii.           promptly after this Amendment is fully executed and delivered,
Landlord shall perform such additional work as might be necessary to reasonably
achieve a clear separation of the Expansion Space from its supporting utility
infrastructure.

                      c.           If Landlord does not substantially complete
the Demising Work on or before the Demising Deadline, as Tenant’s sole remedy,
Tenant shall have the unqualified right to terminate this Amendment; provided,
however, in order to exercise such termination right, Tenant shall give Landlord
written notice of such termination prior to the earlier of Landlord’s
substantial completion of the Demising Work or within thirty-one (31) days after
the Demising Deadline.

d.           i.           Beginning on the Expansion Space Commencement Date,
Tenant shall be entitled to access the Expansion Space so Tenant can make
Alterations to the Expansion Space. Tenant shall design, construct and install
such Alterations in accordance with the provisions of Section 10-Alterations of
the Lease and Landlord’s then current rules for third-party construction at the
Building.

                                ii.           Landlord shall provide Tenant with
a tenant improvement allowance for the Expansion Space in an amount equal to the
product of Ten Dollars ($10.00) multiplied by the rentable area of the Expansion
Space (i.e., 10,428 rentable square feet) (the “Expansion Space Allowance”).
Landlord shall disburse the Expansion Space Allowance in accordance with
Landlord’s standard leasehold improvement allowance disbursement procedures. The
Expansion Space Allowance shall be applied solely towards the third-party
design, construction and installation costs incurred by Tenant in connection
with the Expansion Space Alterations; provided, however, Tenant shall have the
right to apply up to fifty percent (50%) of the Expansion Space Allowance
towards Tenant’s Relocation Costs.

                                iii.           “Relocation Costs” means
out-of-pocket costs incurred by Tenant in moving Tenant’s business to the
Expansion Space including, without limitation, costs and expenses incurred by
Tenant to (a) relocate telephone switching equipment, including inside wiring
and jacks (excluding the cost to purchase or lease additional equipment); (b)
relocate existing or install new telephone lines; (c) relocate existing data
communication circuit(s) or to install new circuit(s) in lieu of relocating
existing circuit(s); (d) purchase, rent or lease materials used in the
relocation of Tenant’s and its employees’ belongings, furniture or equipment;
and (e) move (labor, material, vehicle usage, supervisor, etc.) Tenant’s and its
employees’ belongings, furniture or equipment to the Expansion Space.

                                iv.           If, as of the sixth (6th) monthly
anniversary of the Expansion Space Commencement Date, any portion of the
Expansion Space Allowance remains unused, the Expansion Space Allowance shall be
deemed reduced by such unused amount and Landlord shall retain such unused
portion of the Expansion Space Allowance.

                                v.           In addition to the Expansion Space
Allowance, Landlord shall provide Tenant with a test-fit allowance in an amount
equal to the product of Ten Cents ($.10) multiplied by the rentable area of the
Expansion Space (i.e., 10,428 rentable square feet).

           7.           Termination.

                      a.           Tenant shall have a one-time right to
terminate the Lease with respect to the Expansion Space (but not with respect to
any other portion of the Premises) as of December 31, 2012 provided Tenant (i)
is not then in default beyond any applicable notice and cure period under the
Lease as amended from time to time, (ii) gives written notice of such
termination to Landlord not later than on March 31, 2012, and (iii) pays to
Landlord, at the time of said notice, an amount equal to the unamortized portion
(as December 31, 2012) of Landlord’s transaction costs incurred in connection
with this Amendment, when such costs are amortized from December 1, 2010 through
the initial Term of the Lease on a straight-line basis at eight percent (8%) per
annum interest. The unamortized costs will be calculated for the following
specific costs: the Expansion Space Allowance plus the Fixed Rent that is abated
(not to exceed three (3) months of Fixed Rent) during the Abatement Period.
Failure to provide written notice and payment by March 31, 2012 will be
considered by Landlord, without the necessity of additional notice, as a waiver
of this right to terminate. Tenant acknowledges and agrees that the termination
payment under this Section is not a penalty and is fair and reasonable
compensation to Landlord for the loss of expected rentals from Tenant over the
remainder of the scheduled Term.

                      b.           Tenant shall have a one-time right to
terminate the Lease with respect to the Expansion Space (but not with respect to
any other portion of the Premises) as of December 31, 2013 provided Tenant (i)
is not then in default beyond any applicable notice and cure period under the
Lease as amended from time to time, (ii) gives written notice of such
termination to Landlord not later than on March 31, 2013, and (iii) pays to
Landlord, at the time of said notice, an amount equal to the unamortized portion
(as December 31, 2013) of Landlord’s transaction costs incurred in connection
with this Amendment, when such costs are amortized from December 1, 2010 through
the initial Term of the Lease on a straight-line basis at eight percent (8%) per
annum interest. The unamortized costs will be calculated for the following
specific costs: the Expansion Space Allowance and plus the Fixed Rent that is
abated (not to exceed three (3) months of Fixed Rent) during the Abatement
Period. Failure to provide written notice and payment by March 31, 2013 will be
considered by Landlord, without the necessity of additional notice, as a waiver
of this right to terminate. Tenant acknowledges and agrees that the termination
payment under this Section is not a penalty and is fair and reasonable
compensation to Landlord for the loss of expected rentals from Tenant over the
remainder of the scheduled Term.

c.           If Tenant terminates the Lease pursuant to Section 35-Termination
of the Lease but Tenant has not theretofore terminated the Lease with respect to
the Expansion Space pursuant to Section 7a or Section 7b of this Amendment, the
Termination Payment payable under Section 35-Termination of the Lease shall be
increased by an amount equal to the unamortized portion (as the Lease
termination date) of Landlord’s transaction costs incurred in connection with
this Amendment, when such costs are amortized from December 1, 2010 through the
Lease termination date on a straight-line basis at eight percent (8%) per annum
interest. The unamortized costs with respect to the Expansion Space will be
calculated for the following specific costs: the Expansion Space Allowance plus
the Fixed Rent that is abated (not to exceed three (3) months of Fixed Rent)
during the Abatement Period.

           8.           Overtime HVAC Service. Upon Tenant’s reasonable prior
request, Landlord shall furnish the Premises with HVAC service during
non-Working Hours at Landlord’s then-current rate for such service, which rate
is currently $50.00 per hour per floor.

           9.           Brokerage.  Landlord and Tenant each represent and
warrant to the other that it has not entered into any agreement with, or
otherwise had any dealings with, any broker or agent in connection with the
negotiation or execution of this Amendment which could form the basis of any
claim by any such broker or agent for a brokerage fee or commission, finder’s
fee, or any other compensation of any kind or nature in connection herewith, and
each party shall indemnify and hold the other harmless from all costs (including
court costs, investigation costs, and attorneys’ fees), expenses, or liability
for commissions or other compensation claimed by any broker or agent with
respect to this Amendment which arise out of any agreement or dealings, or
alleged agreement or dealings, between the indemnifying party and any such agent
or broker. This Section shall survive the expiration or earlier termination of
the Lease.

           10.           Ratification.  Landlord and Tenant hereby ratify and
confirm that the terms of the Lease as amended by this Amendment, remain in full
force and effect.

           11.           Controlling Document.  Except as expressly set forth to
the contrary in this Amendment, Landlord’s leasing of the Premises to Tenant
shall be upon and subject to the terms and provisions set forth in the Lease.

           12.           Merger; Subsequent Changes. This Amendment constitutes
the entire agreement between the parties with respect to the subject matter
hereof, and all prior discussions and negotiations and agreements regarding the
same are hereby merged in this Amendment. The provisions of this Amendment may
be modified, waived or amended only by an agreement in writing signed by all
parties.

           13.           Binding Effect.  The terms and provisions of this
Amendment shall be binding upon and inure to the benefit of the parties hereto
and their respective successors and permitted assigns under the Lease.

14.           Counterparts. This Amendment may be executed in counterpart, each
of which shall be deemed an original and all of which collectively shall
constitute one and the same document. Any signature on a counterpart of this
Amendment sent by facsimile transmission  shall be deemed valid and binding upon
the party employing the same; provided that such party shall, upon the request
of the other party, promptly provide such other party with a counterpart of this
Amendment bearing an original version of such signature sent by facsimile
transmission.

           15.           OFAC.  Tenant, to the best of Tenant’s information and
belief, represents, warrants and covenants that neither Tenant nor any of its
partners, officers, directors, members or shareholders (i) is listed on the
Specially Designated Nationals and Blocked Persons List maintained by the Office
of Foreign Asset Control, Department of the Treasury (“OFAC”) pursuant to
Executive Order No. 13224, 66 Fed. Reg. 49079 (Sept. 25, 2001) (together with
all other applicable requirements contained in any enabling legislation or other
Executive Orders in respect of such Executive Order, the “Order(s)”) and all
applicable provisions of Title III of the USA Patriot Act (Public Law No. 107-56
(October 26, 2001)); (ii) is listed on the Denied Persons List and Entity List
maintained by the United States Department of Commerce; (iii) is listed on the
List of Terrorists and List of Disbarred Parties maintained by the United States
Department of State, (iv) is listed on any list or qualification of “Designated
Nationals” as defined in the Cuban Assets Control Regulations 31 C.F.R. Part
515; (v) is listed on any other publicly available list of terrorists, terrorist
organizations or narcotics traffickers maintained by the United States
Department of State, the United States Department of Commerce or any other
governmental authority or pursuant to the Order, the rules and regulations of
OFAC (including without limitation the Trading with the Enemy Act, 50 U.S.C.
App. 1-44; the International Emergency Economic Powers Act, 50 U.S.C. §§
1701-06; the unrepealed provision of the Iraq Sanctions Act, Public Law No.
101-513; the United Nations Participation Act, 22 U.S.C. § 2349 as-9; The Cuban
Democracy Act, 22 U.S.C. §§ 6001-10; The Cuban Liberty and Democratic Solidarity
Act, 18 U.S.C. §§ 2332d and 233; and The Foreign Narcotic Kingpin Designation
Act, Public Law No. 106-120 and 107-108, all as may be amended from time to
time); (vi) is engaged in activities prohibited in the Orders; or (vii) has been
convicted, pleaded nolo contendere, indicted, arraigned or custodially detained
on charges involving money laundering or predicate crimes to money laundering,
drug trafficking, terrorist-related activities or other money laundering
predicate crimes or in connection with the Bank Secrecy Act (31 U.S.C. §§ 5311
et. seq.).  Tenant hereby agrees to defend, indemnify, and hold harmless
Landlord from and against any and all claims, damages, losses, risks,
liabilities, and expenses (including attorney's fees and costs) arising from or
related to any breach of the foregoing representation, warranty and
covenant.  The breach of this representation, warranty and covenant by Tenant
shall be an immediate Event of Default under the Lease without cure.

           16.           Governing Law. This Amendment and any modifications
hereof shall be governed and construed in accordance with the laws of the State
of Maryland, without regard to its choice of law principles.

           17.           Press Releases. Landlord shall have the right, after
notice to and approval by Tenant, to include general information relating to
this Amendment, including Tenant’s name, the Building and the square footage of
the Premises  in  press releases relating to Landlord’s and its affiliates’
leasing activity. Tenant’s approval will not be unreasonably
withheld.   Information relating to rental rates will not be released without
Tenant’s prior written consent, which consent shall not be unreasonably
withheld, conditioned or delayed.

[SIGNATURES FOLLOW]

           IN WITNESS WHEREOF, Landlord and Tenant have caused this Amendment to
be executed under seal as of the day and year first above stated.

LANDLORD:

BRANDYWINE RESEARCH LLC,
a Delaware limited liability company

By: /s/ Glen M.
Holsinger                                                      [SEAL]
Name: Glen Holsinger
Title: Vice President – Asset Management

TENANT:

EMERGENT BIOSOLUTIONS INC.,
a Delaware corporation

By: /s/ Kyle Keese                                            [SEAL]
Name: Kyle W. Keese
Title: SVP Manufacturing Operations

Exhibit A

Floor Plan of Expansion Space

Exhibit B

Lobby Plan

Rider No. 1

Expansion Space Fixed Rent

Fixed Rent for the Expansion Space shall be as follows:

Expansion Space Lease Year
   
Fixed Rent per annum per rsf of Expansion Space
   
 
Monthly Installments
   
 
Annual Fixed Rent
    1 *   $ 25.00     $ 21,725.00     $ 260,700.00     2     $ 25.69     $
22,324.61     $ 267,895.32     3     $ 26.39     $ 22,932.91     $ 275,194.92  
  4     $ 27.12     $ 23,567.28     $ 282,807.36     5     $ 27.87     $
24,219.03     $ 290,628.36     6     $ 28.63     $ 24,879.47     $ 298,553.64  
7 through initial Expiration Date
    $ 29.42     $ 25,565.98     $ 306,791.76  

*Tenant shall be entitled to an abatement of, and Landlord hereby waives
Tenant’s obligation to pay, installments of Fixed Rent with respect to the
Expansion Space for the period beginning on the Expansion Space Commencement
Date and continuing through June 30, 2011 (the “Abatement Period”); provided,
however, if Landlord has not substantially completed the Demising Work within
thirty-one (31) days after the full execution and delivery of this Amendment
(which period shall be extended on a day for day basis for each day that
Landlord is delayed in substantially completing the Demising Work due to any
delay caused by Tenant and/or by any Force Majeure Delay) (the “Abatement
Deadline”), the Abatement Period shall be extended on a day for day basis for
each day after the Abatement Deadline until the day on which Landlord
substantially completes the Demising Work. Nothing herein contained shall be
deemed to diminish or relieve Tenant of its obligation to pay in accordance with
the terms of the Lease (as amended from time to time) all sums owed by Tenant to
Landlord under the Lease as amended from time to time during the Abatement
Period other than Fixed Rent for the Expansion Space. Commencing on the first
day following the Abatement Period, the regular installments of Fixed Rent for
the Expansion Space shall then and thereafter be payable in full by Tenant in
accordance with the terms of the Lease as amended from time to time.

“Expansion Space Lease Year” means each period of twelve (12) successive months
beginning on the Expansion Space Commencement Date and each anniversary thereof,
except that the last Expansion Space Lease Year of the Term might contain fewer
than twelve (12) months if the period between the expiration of the then
preceding Expansion Space Lease Year and the Expiration Date of the Lease
contains fewer than twelve (12) months.