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                                                           EXHIBIT NO. 10.48

     Confidential materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

                      HAP(TM) FOCUS TRIAL LICENSE AGREEMENT

This AGREEMENT (the "Agreement") is made as of the 21st day of December 2001
(the "Effective Date"), by and between Genaissance Pharmaceuticals, Inc., a
Delaware Corporation with its principal place of business at Five Science Park,
New Haven, CT 06511 ("Genaissance"), and Biogen, Inc., a Massachusetts
corporation with offices at 14 Cambridge Center, Cambridge, MA 02142, USA
("Biogen"). Genaissance and Biogen are sometimes referred to herein as a party
and collectively as the parties. Reference to a party herein includes a
reference to its Affiliates (as hereinafter defined) unless otherwise indicated.

                                    RECITALS

         WHEREAS, Genaissance has developed a fully integrated solution for
connecting genomic variation to drug response and disease susceptibility, which
is called HAP(TM) Technology, and which combines Genaissance's proprietary
haplotype markers, called HAP(TM) Markers (as hereinafter defined); and

         WHEREAS, Biogen is interested in obtaining limited access to the
HAP(TM) Technology for research and development purposes; and

         WHEREAS, Genaissance is willing to grant Biogen such limited access
upon the terms and conditions set forth below.

         NOW THEREFORE, in consideration of the premises and of the covenants
herein contained, the parties hereto mutually agree as follows:

                                    ARTICLE 1
                                   DEFINITIONS

         1.1 "AFFILIATE," shall mean any corporation, fern, partnership or other
legal entity which, directly or indirectly, controls, is controlled by, or is
under common control with a Party. For ' purposes of this definition, control
shall mean the direct or indirect ownership of more than fifty percent (50%) of
(i) the stock shares entitled to vote for the election of directors or (ii)
ownership interest of any such corporation, firm, partnership or other legal
entity.

         1.2 "BIOGEN GENE ALLOCATION" shall mean the list of Genes to be
attached hereto as Exhibit B, PROVIDED THAT the list shall contain [**] Genes.
Exhibit B may be amended from time to time during the Term and all provisions of
the Agreement shall apply thereto.

         1.3 "BIOGEN KNOW-HOW" shall mean any and all proprietary data,
information, know-how, inventions, trade secrets, copyrights, regulatory
submissions or other intellectual property

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of any kind, other than Patent Rights, owned or controlled by Biogen, as of the
Effective Date or during the Term of this Agreement.

         1.4 "BIOGEN PATENT RIGHTS" shall mean Patent Rights owned or controlled
by Biogen.

         1.5 "GENAISSANCE KNOW-HOW" shall mean any and all proprietary data,
information, know-how, inventions, trade secrets, copyrights, regulatory
submissions or other intellectual property of any kind, other than Patent
Rights, owned or controlled by Genaissance, as of the Effective Date, including,
without limitation, any data on the sequence, frequency and distribution of
HAP(TM) Markers contained in the Database.

         1.6 "GENAISSANCE PATENT RIGHTS" shall mean individually and
collectively, the HAP(TM) Marker Patent Rights and the HAP(TM) Marker
Association Patent Rights.

         1.7 "GENE" shall mean a human nucleic acid sequence (including allelic
variations thereof) (a) that encodes a designated protein and (b) that has known
genomic regions as set forth in Exhibit A hereto.

         1.8 "HAP FOCUS(TM) DATABASE" shall mean a database provided in
electronic format (such as excel spreadsheet) and/or as a hard copy that
contains annotated data on the sequence, frequency and distribution of HAP(TM)
Markers for the Biogen Gene Allocation, with such HAP(TM) Markers generated by
examining genomic DNA from the Index Repository as more fully described in
Exhibit A hereto.

         1.9 "HAP(TM) MARKER" shall mean [**] a Gene [**] that (i) is contained
in the HAP FOCUS(TM) Database and (ii) was not known to Biogen prior to the
First Installation Date .

         1.10 "HAP(TM) MARKER PATENT RIGHTS" shall mean Patent Rights claiming a
HAP(TM) Marker or use thereof.

         1.11 "INDEX REPOSITORY" shall mean Genaissance's proprietary collection
of immortalized cell lines established from unrelated individuals from various
geographical origins and from members of extended families.

         1.12 "PATENT RIGHTS" shall mean patents or patent applications owned or
controlled (with the right to grant licenses) by a party to this agreement. More
particularly, Patent Rights include (i) any United States or foreign patent
application, (ii) any United States patent or foreign patent issuing from such
patent application and (iii) any continuation, continuation-in-part (to the
extent the claims in such continuation-in-part application are directed to
subject matter specifically described in such prior patent application),
divisional, reissue, re-examination, renewal, substitution, addition, extension,
supplementary protection certificate or foreign counterpart thereof of any of
the foregoing.

         1.13 "SNP" shall mean a single nucleotide polymorphism.

         1.14 "TERM" shall have the meaning set forth in Section 9.1 hereof.

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         1.15 "THIRD PARTY" shall mean any entity other than Genaissance or
Biogen and their respective Affiliates.

                                    ARTICLE 2
                                GRANTS OF RIGHTS

         2.1 NON-EXCLUSIVE R&D LICENSE TO THE HAP FOCUS(TM) DATABASE. Subject to
the terms of this Agreement, Genaissance hereby grants to a [**] non-exclusive
license, without the right to grant sublicenses, under Genaissance Patent Rights
and Genaissance Know-How to access and use the HAP FOCUS(TM) Database solely for
research and development during the Term. For avoidance of doubt, Biogen shall
not have the right to share the HAP FOCUS(TM) Database with any Third Party.

         2.2 RESTRICTIONS ON USE OF THE HAP FOCUS(TM) DATABASE. Biogen's use of
the HAP FOCUS(TM) Database shall be subject to the following conditions:

                  (a)      Biogen agrees to make copies of the HAP FOCUS(TM)
                           Marker only to the extent reasonably necessary to
                           perform such research and development during the term
                           of this Agreement, and agrees that all such copies
                           will be treated as Confidential Information of
                           Genaissance.

                  (b)      Except as specifically authorized hereunder, Biogen
                           shall not sell, transfer, publish, disclose, display
                           or otherwise make available any portion of the HAP
                           FOCUS(TM) Database to Third Parties.

                  (c)      Biogen agrees to secure and protect the HAP FOCUS(TM)
                           Database in a manner reasonably consistent with the
                           maintenance of rights therein, and in accordance with
                           the terms of this Agreement, and to take appropriate
                           action by instruction or agreement with its employees
                           who are permitted access to the HAP FOCUS(TM)
                           Database to satisfy its obligations hereunder. Biogen
                           shall cooperate with and reasonably assist
                           Genaissance in identifying and preventing any
                           unauthorized use, copying or disclosure of the HAP
                           FOCUS(TM) Database.

                  (d)      Notwithstanding the foregoing, Biogen shall, subject
                           to any pre-existing rights of Third Parties or
                           Genaissance, have an unlimited right to use, for
                           research and development, any and all information
                           from its use of and access to the HAP FOCUS(TM)
                           Database.

         2.3 NON-EXCLUSIVE R&D LICENSE TO HAP(TM) MARKERS. Subject to the terms
of this Agreement, Genaissance hereby grants to Biogen a worldwide, [**]
non-exclusive license, without the right to grant sublicenses, under Genaissance
Patent Rights and Know-How to use the HAP(TM) Markers solely for research and
development during the Term. For avoidance of doubt, Biogen shall not have the
right to share the HAP FOCUS(TM) Database with any Third Party.

         2.4 RESERVATION OF RIGHTS. Notwithstanding the rights granted to Biogen
under this Article 2, Genaissance at all times reserves (i) its rights to the
HAP(TM) Markers for information contained in the HAP FOCUS(TM) Database and (ii)
its right to use such HAP(TM) information to

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research, develop, have developed, use, manufacture, have manufactured, sell and
have sold products, including the right to grant licenses to Third Parties with
respect to any intellectual property rights related to such purposes, PROVIDED
THAT, no such license shall limit the grants of right to Biogen hereunder.
Biogen at all times reserves its rights to Biogen Know-How and Biogen Patent
Rights.

         2.5 NO GRANT OF OTHER RIGHTS. Except as otherwise expressly provided in
this Agreement, under no circumstances shall a party hereto, as a result of this
Agreement, obtain any ownership interest in or other right to any technology,
know-how, patents, patent applications, data, products, or biological materials
of the other party, including items owned, controlled or developed by the other
party, or transferred by the other party to said party, at any time pursuant to
this Agreement. Any compounds, technology or know-how derived, developed or
acquired by either party independent of use of or access to the HAP FOCUS(TM)
shall be the property of such party.

                                    ARTICLE 3
                   DELIVERY AND USE OF HAP FOCUS(TM) DATABASE

         3.1 HAP(TM) MARKER DISCOVERY. Biogen shall deliver to Genaissance, from
time to time during the Term, a description of the Biogen Gene Allocation, which
description shall be attached hereto as Exhibit B. Genaissance shall promptly
initiate a program to discover HAP(TM) Markers for each of the Genes in the
Biogen Gene Allocation using genomic DNA from the Index Repository as described
in Exhibit A and using its proprietary HAP(TM) Builder process. This step will
not be necessary for those Genes for which HAP(TM) Markers have already been
discovered as defined in Exhibit A.

         3.2 DELIVERY OF HAP FOCUS(TM) DATABASE. Genaissance shall deliver to
Biogen the HAP FOCUS(TM) database in an electronic format such as an excel
spreadsheet and in hard copy. The delivery date shall be no later than three (3)
months from the Effective Date.

         3.3 TECHNICAL SUPPORT. Genaissance shall provide technical support
through a primary contact person who shall be accessible by telephone and e-mail
between the hours of 8.00 a.m. and 6:00 p.m. U. S. Eastern Time, Monday through
Friday or through additional on-site assistance. Genaissance's actual and
reasonable travel costs incurred in providing such additional on-site assistance
shall be reimbursed by Biogen.

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                                    ARTICLE 4
                                    PAYMENTS

         4.1 LICENSE FEE. In consideration of the rights granted to Biogen under
Article 2 and Biogen agrees to pay Genaissance a fee of [**] dollars ($[**])
[**], to be paid within [**] business days after delivery of the HAP FOCUS(TM)
Database to Biogen.

         4.2 PAYMENT. Payments to be made by Biogen to Genaissance under this
Agreement shall be payable in United States dollars and shall be paid by
immediately available funds to such bank account in the State of Connecticut as
is designated in writing by Genaissance from time to time.

                                    ARTICLE 5
                              INTELLECTUAL PROPERTY

         5.1 OWNERSHIP OF INTELLECTUAL PROPERTY

                  5.1.1 OWNERSHIP OF THE HAP FOCUS(TM) DATABASE. Subject to the
         rights and licenses granted under this Agreement, Genaissance shall
         have sole ownership of the HAP FOCUS(TM) Database all information
         contained therein.

                  5.1.2 OWNERSHIP OF HAP(TM) MARKERS. Genaissance shall have
         sole ownership of all right, title and interest in all HAP(TM) Markers,
         and all HAP(TM) Marker Patent subject to Biogen's right to use the
         HAP(TM) Markers pursuant to the terms of this Agreement.

                  5.1.3 BIOGEN INVENTIONS. Any and all inventions made or
         conceived solely by Biogen in the course of using information from the
         HAP FOCUS(TM) Database shall be owned solely by Biogen, and Biogen
         shall be under no obligation to transfer any rights to such inventions
         to Genaissance. For purposes of this section, inventorship shall be
         determined according to principles of United States patent law.

                  5.1.4 JOINT INVENTIONS. Any and all inventions made or
         conceived jointly by at least one Biogen employee and at least one
         Genaissance shall be owned jointly by Biogen and Genaissance ("Joint
         Invention"). Nothing in this Agreement shall be construed as obligating
         either party to convey its ownership rights in a Joint Invention to the
         other party.. For purposes of this section, inventorship shall be
         determined according to principles of United States patent law.

                                    ARTICLE 6
                                 CONFIDENTIALITY

         6.1 CONFIDENTIAL INFORMATION. Confidential Information shall mean,
subject to the limitations and exceptions described in Section 6.2.2, any
information and data received by a party from the other party in connection with
the performance of this Agreement. In the case of Biogen as receiving party,
Confidential Information shall include without limitation, including but not
limited to HAP(TM) Markers, contained in the HAP FOCUS(TM) Database, delivered
to Biogen. Genaissance acknowledges and agrees that Biogen shall be the sole
owner of any data and research results generated by Biogen using the HAP
FOCUS(TM) Database or HAP(TM) Markers.

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Genaissance further acknowledges and agrees that, subject to the limitations of
Section 6.4 below, Biogen shall be free to publish any data and research results
generated by Biogen using the HAP FOCUS(TM) Database or HAP(TM) Markers. In the
case of Genaissance as receiving party, Confidential information shall include
without limitation any information and data relating to Biogen's research and
development using the HAP FOCUS(TM) Database or HAP(TM) Markers, including
Biogen Gene allocation list. Confidential Information shall include, subject to
the limitations and exceptions described in Section 6.2.2, all information and
data not described in the preceding sentences of this paragraph, but supplied by
either party to the other in connection with this Agreement and marked
"Confidential."

         6.2 NONDISCLOSURE OBLIGATIONS.

                  6.2.1 GENERAL. Except as otherwise provided in this Article 6,
         during the term of this Agreement and for a period of ten (10) years
         thereafter, the receiving party shall use the Confidential Information
         only for purposes specifically authorized under this Agreement, and
         shall not publish any portion of the Confidential Information or
         disclose it to any third party without the prior written consent of the
         disclosing party.

                  6.2.2 LIMITATIONS. The parties agree that the receiving party
         shall not have any obligation of confidentiality with respect to such
         Confidential Information that; (a) is or becomes part of the public
         domain other than by unauthorized acts of the party obligated not to
         disclose such Confidential Information; (b) can be shown by written
         documents to have been disclosed to the receiving party by a Third
         Party, provided such Confidential Information was not obtained by such
         Third Party directly or indirectly from the other party to this
         Agreement pursuant to a confidentiality agreement; (c) prior to
         disclosure under this Agreement, was already in the possession of the
         receiving party, provided such Confidential Information was not
         obtained directly or indirectly from the other party to this Agreement
         pursuant to a confidentiality agreement; (d) can be shown by written
         documents to have been independently developed by the receiving party
         without breach of any of the provisions of this Agreement; (e) is
         disclosed by the receiving party pursuant to an order or demand issued
         by a court or governmental agency or as otherwise required by law;
         PROVIDED, HOWEVER, that the receiving party notifies the other party
         prior to disclosure, giving such other party sufficient advance notice
         to permit it to seek a protective order or other similar order with
         respect to such Confidential Information AND PROVIDED, FURTHER, that
         the receiving party furnishes only that portion of the Confidential
         Information which it is advised by counsel is legally required whether
         or not a protective order or other similar order is obtained by the
         other party; or (f) where the receiving parry reasonably believes such
         disclosure is reasonably necessary or appropriate to fulfill its
         obligations or exercise its rights under this Agreement, with such
         disclosure being limited to: (i), consultants, outside contractors and
         clinical investigators, on a need-to-know basis and on condition that
         such entities or persons agree to keep the Confidential Information
         confidential for the same time periods and to the same extent as such
         party is required to keep the Confidential Information confidential;
         and (ii) government or other regulatory authorities to the extent that
         such disclosure is reasonably necessary to obtain patents or
         authorizations to conduct clinical trials of, and to commercially
         market, products pursuant to this Agreement.

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         6.3 INJUNCTIVE RELIEF. The parties understand and agree that remedies
at law may be inadequate to protect against any breach of any of the provisions
of this Article 6 by either party or their employees, agents, officers or
directors or any other person acting in concert with it or on its behalf.
Accordingly, each party may be entitled to the granting of injunctive relief by
a court of competent jurisdiction against any action that constitutes any such
breach of this Article 6.

         6.4 PUBLICATION. Either party may publish or present data and/or
results generated utilizing the HAP(TM) Database or HAP(TM) Markers, provided,
however, that the party proposing publication ("Submitting Party") shall provide
a copy of the proposed publication to the other party ("Reviewing Party") at
least forty-five (450 days prior to a proposed date of public presentation or
submission for publication. The Reviewing Party shall have thirty (30) days from
its receipt of such proposed publication in which to notify the Submitting Party
in writing of any specific objections to the proposed publication, based on
either the need to seek patent protection and/or concern regarding disclosure of
Confidential Information of the Reviewing Party. If the Reviewing Party objects
to the proposed publication, the Submitting Party agrees to delay submission or
public presentation of the proposed publication for up to an additional sixty
(60) days) after receipt of the objection, to permit filing of a patent
application on potentially patentable subject matter in the proposed
publication. Upon request, the Submitting Party agrees to delete from the
proposed publication any Confidential Information of the Reviewing Party, or
otherwise to revise the proposed publication in manner mutually acceptable to
both parties.

                                    ARTICLE 7
                         REPRESENTATIONS AND WARRANTIES

         7.1 REPRESENTATIONS, WARRANTIES AND COVENANTS OF GENAISSANCE.
Genaissance represents and warrants to and covenants with Biogen that:

                  (a) Genaissance is a corporation duly organized, validly
existing and in corporate good standing under the laws of Delaware;

                  (b) Genaissance has the legal right, authority and power to
enter into this Agreement, and to extend the rights and licenses granted to
Biogen in this Agreement;

                  (c) Genaissance has taken all necessary action to authorize
the execution, delivery and performance of this Agreement;

                  (d) upon the execution and delivery of this Agreement, this
Agreement shall constitute a valid and binding obligation of Genaissance
enforceable 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);

                  (e) the performance of its obligations tinder this Agreement
will not conflict with its charter documents or result in a breach of any
agreements, contracts or other arrangements to which it is a party;

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                  (f) to the best of Genaissance's knowledge but without
independent investigation, the performance of Genaissance's obligations under
this Agreement, including without limitation the delivery to Biogen of the HAP
FOCUS(TM) Database and the contents of the HAP FOCUS(TM) Database, will not
infringe, or shall be exempt from infringement of, any issued patent or valid
copyright of any Third Party;

                  (g) to the best of Genaissance's knowledge but without
independent investigation, the methods used by Genaissance for identifying the
HAP(TM) Markers do not infringe, or shall be exempt from infringement of, any
issued patent or valid copyright of any Third Party; and

                  (h) Genaissance will not during the term of this Agreement
enter into any agreements, contracts or other arrangements that would be
inconsistent with its obligations under this Agreement.

         7.2 REPRESENTATIONS, WARRANTIES AND COVENANTS OF BIOGEN. Biogen
represents and warrants to and covenants with Genaissance that:

                  (a) Biogen is a corporation duly organized, validly existing
and in corporate good standing under the laws of Massachusetts;

                  (b) Biogen has the legal right, authority and power to enter
into this Agreement, and to extend the rights and licenses granted to
Genaissance in this Agreement;

                  (c) Biogen has taken all necessary action to authorize the
execution, delivery and performance of this Agreement;

                  (d) upon the execution and delivery of this Agreement, this
Agreement shall constitute a valid and binding obligation of Biogen enforceable
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);

                  (e) the performance of its obligations under this Agreement
will not conflict with Biogen's charter documents or result in a breach of any
agreements, contracts or other arrangements to which it is a party;

                  (f) all products or services requested by Biogen hereunder are
solely for uses reasonably related to the development and submission of
information to the FDA; and

                  (g) Biogen will not after the Effective Date enter into any
agreements, contracts or other arrangements that would be inconsistent with its
obligations under this Agreement.

         7.3 WARRANTY DISCLAIMER. EXCEPT AS OTHERWISE EXPRESSLY PROVIDED IN THIS
AGREEMENT, NEITHER PARTY MAKES ANY WARRANTY WITH RESPECT TO THE HAP FOCUS(TM)
DATABASE, PATENT RIGHTS, GOODS, SERVICES OR OTHER

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SUBJECT MATTER OF THIS AGREEMENT AND HEREBY DISCLAIMS WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT WITH
RESPECT TO ANY AND ALL OF THE FOREGOING. IN ADDITION, BIOGEN ACKNOWLEDGES THAT
THE HAP FOCUS(TM) DATABASE MAY CONTAIN INFORMATION THE ACQUISITION OR USE OF
WHICH IS COVERED BY ONE OR MORE VALID PATENTS OF THIRD PARTIES. GENAISSANCE
MAKES NO WARRANTY THAT THE HAP FOCUS(TM) DATABASE DOES NOT CONTAIN ERRORS OR
THAT THE HAP FOCUS(TM) DATABASE CONTAINS ALL HAP(TM) MARKERS THAT ARE ACTUALLY
PRESENT BUT NOT DETECTED 1N THE INDEX REPOSITORY.

         7.4 LIMITED LIABILITY. NOTWITHSTANDING ANYTHING ELSE IN THIS AGREEMENT
OR OTHERWISE TO THE CONTRARY, NEITHER GENAISSANCE NOR BIOGEN WILL BE LIABLE WITH
RESPECT TO ANY SUBJECT MATTER OF THIS AGREEMENT UNDER ANY CONTRACT, NEGLIGENCE,
STRICT LIABILITY OR OTHER LEGAL OR EQUITABLE THEORY FOR (I) ANY PUNITIVE,
EXEMPLARY, INCIDENTAL OR CONSEQUENTIAL DAMAGES OR LOST PROFITS OR (II) COST OF
PROCUREMENT OF SUBSTITUTE GOODS, TECHNOLOGY OR SERVICES.

                                    ARTICLE 8
                                    INDEMNITY

         8.1 BIOGEN INDEMNITY OBLIGATIONS. Biogen will, at its own expense,
indemnify and promptly reimburse Genaissance for the defense of, and hold
harmless Genaissance and its officers and employees, from and against any and
all claims, actions, liabilities, losses, damages, judgments, grants, costs and
expenses (including attorneys' fees) resulting from or pertaining to (a)
Biogen's use or operation of the HAP(TM) Markers or the HAP FOCUS(TM) Database
or (b) a breach of any of the warranties made hereunder by Biogen.

         8.2 GENAISSANCE INDEMNITY OBLIGATIONS. Genaissance agrees to defend,
indemnify and hold Biogen and its employees and agents harmless from and against
any and all claims, actions, losses, damages, judgments, grants or expenses
(including attorneys' fees) arising as a result of (a) claims by employees or
contractors of Genaissance for bodily injury, death or property damage arising
out of the performance by Genaissance of any activities under this Agreement;
(b) the negligence, recklessness or intentional misconduct of Genaissance in
connection with its activities under this Agreement or (c) a breach of any of
the warranties made hereunder by Genaissance.

         8.3 LIMITATION ON INDEMNITY OBLIGATIONS. Neither party nor its
respective employees and agents shall be entitled to the indemnities set forth
in Section 8.1 to the extent that the claim, loss, damage or expense for which
indemnification is sought was caused by a grossly negligent or intentional act
or omission by the other party, its directors, officers, employees or authorized
agents.

         8.4 INFRINGEMENT INDEMNIFICATION. Biogen shall indemnify, defend and
hold Genaissance and its employees and agents harmless from all claims, losses,
damages or expenses (including attorneys' fees) arising out of or resulting from
any claims, judgments or adjudications against Genaissance that Biogen's used of
any HAP(TM) Marker or infringes any patent, trade

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secret or similar proprietary rights of a Third Party. Genaissance and its
employees and agents shall not be entitled to the indemnities set forth in this
Section 8.4 where the claim, loss, damage or expense for which indemnification
is sought arises out of the infringement of any patent, trade secret or similar
proprietary right of a Third party of which Genaissance was aware at the time
Genaissance provided access to a HAP(TM) Marker.

         8.5 PROCEDURE. If the party being indemnified hereunder or its
respective employees or agents (the "Indemnitee") intends to claim
indemnification under this Article 8, the Indemnitee shall promptly notify the
other party (the "Indemnitor") of any loss, claim, damage, liability or action
in respect of which the Indemnitee intends to claim such indemnification, and
the Indemnitor shall assume the defense thereof with counsel mutually
satisfactory to the parties; provided, however, that an Indemnitee shall have
the right to retain its own counsel, with the fees and expenses to be paid by
the Indemnitor, if representation of such Indemnitee by the counsel retained by
the Indemnitor would be inappropriate due to actual or potential differing
interests between such Indemnitee and any other party represented by such
counsel in such proceedings. The indemnity agreement in this Article 8 shall not
apply to amounts paid in settlement of any loss, claim, damage, liability or
action if such settlement is effected without the consent of the Indemnitor,
which consent shall not be withheld unreasonably. The failure to deliver notice
to the Indemnitor within a reasonable time after the commencement of any such
action, if prejudicial to its ability to defend such action, shall relieve such
Indemnitor of any liability to the Indemnitee under this Article 8, but the
omission so to deliver notice to the Indemnitor will not relieve it of any
liability that it may have to any Indemnitee otherwise than under this Article
8. The Indemnitee under this Article 8, its employees and agents, shall
cooperate fully with the Indemnitor and its legal representatives in the
investigation of any action, claim or liability covered by this indemnification.
The Indemnitor shall additionally be liable to pay the reasonable legal costs
and attorneys' fees incurred by the Indemnitee in establishing its claim for
indemnity.

                                    ARTICLE 9
                           EXPIRATION AND TERMINATION

         9.1 TERM OF AGREEMENT. Unless this Agreement is sooner terminated in
accordance with the provisions of this Article 9, the "Term" of this Agreement
shall commence on the Effective Date and expire two (2) years from the Effective
Date.

         9.2 EVENTS OF DEFAULT.

                  9.2.1 DEFAULT BY EITHER PARTY. An Event of Default shall have
         occurred upon (i) the occurrence of a material breach of this Agreement
         (other than an Event of Default described in Section 9.3.2) if the
         breaching party fails to remedy such breach within thirty (30) days
         after written notice thereof by the non-breaching party or (ii) the
         bankruptcy, insolvency, dissolution or winding up of a parry.

                  9.2.2 DEFAULT BY BIOGEN. An Event of Default shall have
         occurred if Biogen fails to make any payments due hereunder, ten (10)
         business days after Genaissance delivers written notice thereof to
         Biogen specifying such failure and its claim of right to

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         terminate, unless Biogen makes such payments plus interest within such
         ten (10) day period.

         9.3 EFFECT OF AN-EVENT OF DEFAULT.

                  9.3.1 REMEDIES AVAILABLE TO GENAISSANCE. In the event that an
         Event of Default occurs relating to Biogen and Biogen fails to cure
         such default during any applicable cure period, Genaissance shall have
         the right, at its option exercisable in its sole discretion, in
         addition to any other rights or remedies available to it at law or in
         equity, to terminate this Agreement upon notice thereof to Biogen, in
         which case (i) the options and licenses granted to Biogen pursuant to
         Article 2 shall terminate and (ii) any and all information and
         materials provided by Genaissance pursuant to this Agreement
         (including, without limitation, all copies of the HAP FOCUS(TM)
         Database), and any copies thereof (including electronic copies) shall
         be promptly returned by Biogen to Genaissance, and Biogen shall delete
         all copies of the HAP FOCUS(TM) Database from all computers at its site
         on which such information has been installed or transmitted.

                  9.3.2 REMEDIES AVAILABLE TO BIOGEN. In the event that an Event
         of Default occurs relating to Genaissance and Genaissance fails to cure
         such default within the applicable cure period, then Biogen shall have
         the right, at its option exercisable in its sole discretion, to seek
         any rights or remedies available to it at law or in equity, subject to
         the limitations set forth in Section 7.4 and Section 10.6 hereof.

         9.4 EFFECT OF EXPIRATION OF THE TERM PERIOD. Upon the expiration of the
Term Period, Biogen shall destroy all copies of the HAP FOCUS(TM) Database, and
certify the completion of such steps in writing to Genaissance.

         9.5 EFFECT OF EXPIRATION OR TERMINATION OF AGREEMENT. The expiration or
termination of this Agreement shall not relieve the parties of any obligation
accruing prior to such expiration or termination. The provisions of Articles 5,
6, 8, 9 and 10, Sections 7.3 and 7.4 hereof, and the license granted to Biogen
pursuant to Section 2.4 hereof shall survive the expiration or termination of
this Agreement.

                                   ARTICLE 10
                                  MYSCELLANEOUS

         10.1 FORCE MAJEURE. Neither party shall be held liable or responsible
to the other party nor be deemed to have defaulted under or breached this
Agreement for failure or delay in fulfilling or performing any term of this
Agreement when such failure or delay is caused by or results from causes beyond
the reasonable control of the affected party, including but not limited to fire,
floods, embargoes, war, acts of war (whether war is declared or not),
insurrections, riots, civil commotions, strikes, lockouts or other labor
disturbances, acts of God or acts, omissions or delays in acting by any
governmental authority or the other party; PROVIDED, HOWEVER, that the party so
affected shall use reasonable commercial efforts to avoid or remove such causes
of nonperformance, and shall continue performance hereunder with reasonable
dispatch whenever such causes are removed. Either party shall provide the other
party with prompt written notice of

                                       11
<Page>

any delay or failure to perform that occurs by reason of FORCE MAJEURE. The
parties shall mutually seek a resolution of the delay or the failure to perform
as noted above.

         10.2 ASSIGNMENT. This Agreement may not be assigned or otherwise
transferred by either party without the consent of the other party, such consent
not to be unreasonably withheld or delayed; PROVIDED, however, that either
Genaissance or Biogen may, without such consent, assign its rights and
obligations under this Agreement (i) to any Affiliate, or (ii) in connection
with a merger, consolidation or sale of substantially all of such party's assets
to an unrelated Third Party; PROVIDED, HOWEVER, that such party's rights and
obligations under this Agreement shall be assumed by its successor in interest
in any such transaction and shall not be transferred separate from all or
substantially all of its other business assets, including those business assets
that are the subject of this Agreement. Any purported assignment in violation of
the preceding sentence shall be void. Any permitted assignee shall assume all
obligations of its assignor under this Agreement.

         10.3 SEVERABILITY. Each party hereby agrees that it does not intend to
violate any public policy, statutory or common laws, rules, regulations, treaty
or decision of any government agency or executive body thereof of any country or
community or association of countries. Should one or more provisions of this
Agreement be or become invalid, the parties hereto shall substitute, by mutual
consent, valid provisions for such invalid provisions which valid provisions in
their economic effect are sufficiently similar to the invalid provisions that it
can be reasonably assumed that the parties would have entered into this
Agreement with such valid provisions. In case such valid provisions cannot be
agreed upon, the invalidity of one or several provisions of this Agreement shall
not affect the validity of this Agreement as a whole, unless the invalid
provisions are of such essential importance to this Agreement that it is to be
reasonably assumed that the parties would not have entered into this Agreement
without the invalid provisions.

         10.4 NOTICES. Any consent, notice or report required or permitted to be
given or made under this Agreement by one of the parties hereto to the other
shall be in writing, delivered personally or by facsimile (and promptly
confirmed by telephone, personal delivery or courier) or courier, postage
prepaid (where applicable), addressed to such other party at its address
indicated below, or to such other address as the addressee shall have last
furnished in writing to the addressor and shall be effective upon receipt by the
addressee.

         If to Genaissance:        Genaissance Pharmaceuticals, Inc.
                                   Five Science Park
                                   New Haven, CT 06511
                                   Attention:  Krishnan Nandabalan, Ph.D.
                                   Telephone:  (203) 786-3445
                                   Facsimile:  (203) 562-9377

         If to Biogen:             Biogen, Inc.
                                   14 Cambridge Center
                                   Cambridge, MA 02142
                                   Attention: Vice President-General Counsel
                                   Fax:  (617) 679-2838

                                       12
<Page>

         10.5 APPLICABLE LAW. This Agreement shall be governed by and construed
in accordance with the laws of the State of Connecticut, without giving effect
to the choice of laws provisions thereof.

         10.6 ENTIRE AGREEMENT. This Agreement, together with the exhibits
hereto, contains the entire understanding of the parties with respect to the
subject matter hereof. All express or implied agreements and understandings,
either oral or written, heretofore made are expressly merged in and made a part
of this Agreement. This Agreement may be amended, or any term hereof modified,
only by a written instrument duly executed by both parties hereto.

         10.7 PUBLICITY. Except as required by law, Genaissance and Biogen each
agree not to disclose the existence or any terms or conditions of this Agreement
to any Third Party without prior written consent of the other party, which shall
not be withheld unreasonably.

         10.8 HEADINGS. The captions to the several Articles and Sections hereof
are not a part of this Agreement, but are merely guides or labels to assist in
locating and reading the several Articles and Sections hereof.

         10.9 NO PARTNERSHIP. It is expressly agreed that the relationship
between Genaissance and Biogen shall not constitute a partnership, joint venture
or agency. Neither Genaissance nor Biogen shall have the authority to make any
statements, representations or commitments of any kind, or to take any action,
which shall be binding on the other, without the prior consent of the other
party to do so.

         10.10 EXPORTS. The parties acknowledge that the export of technical
data, materials or products is subject to the exporting party receiving any
necessary export licenses and that the parties cannot be responsible for any
delays attributable to export controls which are beyond the reasonable control
of either party. Genaissance and Biogen agree not to export or re-export,
directly or indirectly, any information, technical data, the direct product of
such data, samples or equipment received or generated under this Agreement in
violation of any applicable export control laws or governmental regulations.
Genaissance and Biogen agree to obtain similar covenants from their licensees,
sublicensees and contractors with respect to the subject matter of this Section.

         10.11 WAIVER. The waiver by either party hereto of any right hereunder
or the failure to perform or of a breach by the other parry shall not be deemed
a waiver of any other right hereunder or of any other breach or failure by said
other party whether of a similar nature or otherwise.

                                       13
<Page>

         10.12 COUNTERPARTS. This Agreement may be executed in two counterparts,
each of which shall be deemed an original, but all of which together shall
constitute one and the same instrument.

         IN WITNESS WHEREOF, the parties have caused their duly authorized
officer to execute and deliver this Agreement as of the date first set forth
above.

BIOGEN, INC.                              GENAISSANCE PHARMACEUTICALS, INC.

By:     /s/ T.J. Bucknum                  By:     /s/ K. Nandabalan

Name:   T.J. Bucknum, Esq.                Name:   Krishnan Nandabalan, Ph.D.

Title:  Executive Vice President
        and General Counsel               Title:  Vice President, Alliances

                                       14
<Page>

                                    EXHIBIT A
                            HAP(TM) MARKER DISCOVERY

         The current procedure for discovering HAP(TM) Markers for a Gene is to
sequence, from the Index Repository, ninety-three (93) individual samples of
human genomic DNA and one sample of chimpanzee genomic DNA. The genomic regions
of each Gene, which are targeted for sequencing, are as follows.

         (i) "Exons" shall mean the genomic DNA segments of a Gene whose
sequence information is translated into the protein product of that Gene. The
goal is to obtain sequence information for all Exons of a Gene.

         (ii) "Exon/Intron Junction" shall mean the junctions between the Exons
and the Introns in genomic DNA. Beginning with the initiation codon at one end
of a Gene and ending with the termination codon at the other end of a Gene, the
goal is to obtain sequence information for each Exon/Intron Junction within this
genomic region.

         (iii) "Introns" shall mean the genomic DNA segments of a Gene, which
are located between Exons. Beginning with the initiation codon at one end of a
Gene and ending with the termination codon at the other end of a Gene, the goal
is to obtain a minimum of ten (10) to twenty (20) bases and a maximum of one
hundred (100) bases of sequence information from the Exon/Intron Junction into
the Intron for every Intron within this genomic region.

         (iv) "Promoter" shall mean the region that is immediately upstream of
the genomic segment that is found at the five-prime end of a Messenger RNA
molecule. ("Messenger RNA" shall mean a ribonucleic acid sequence from which the
protein product of a Gene is translated.) The goal is to obtain sequence
information for up to one thousand (1000) bases of the Promoter.

         (v) "Three-Prime Untranslated Region" shall mean the genomic region
immediately downstream from the termination codon of a Gene. The goal is to
obtain sequence information for at least one hundred (100) bases of the
Three-Prime Untranslated Region downstream of the termination codon.

         Specific genomic sequence information is required to meet the 'goals
outlined in (i) through (v) above. If genomic sequence information is available
for a majority of these regions, even if the available genomic sequence
information is not sufficient to meet all of the goals in (i) through (v) above,
a Gene will still be queued for HAP(TM) Marker discovery.

         A Gene shall be considered completely sequenced if sequence information
is obtained for: (i) at least [**] of the [**]; (ii) the [**] containing the
[**]; and (iii) [**]. A specific region targeted for sequencing within a Gene
shall be considered completely sequenced if sequence information is obtained
[**]. However, the presence of runs of guanine and cytosine, secondary structure
or errors in publicly available sequence information may prevent the generation
of sufficient sequence information for that Gene to be considered completely
sequenced as defined above.

         Genaissance shall use commercially reasonable efforts to incorporate
into the HAP FOCUS(TM) Database other information about Genes, including: [**].

                                       15
<Page>

                                    EXHIBIT B
                             Biogen Gene Allocation
                           (To be Supplied by Biogen)

1.       [**]

                                       16<PAGE>

                                                           EXHIBIT NO. 10.49

                        GENAISSANCE PHARMACEUTICALS, INC.
                                Five Science Park
                               New Haven, CT 06511
                                 (203) 773-1450

                                                              February 18, 2002

VIA FACSIMILE AND FEDERAL EXPRESS

[Name Registration Rights Holder]
[Address of Registration Rights Holder]

         Re: Genaissance Pharmaceuticals, Inc. - Registration Rights Waiver
             ---------------------------------------------------------------

Dear Investor:

         On October 18, 2001, Genaissance Pharmaceuticals, Inc. ("Genaissance")
filed a registration statement ("Registration Statement") with the United States
Securities and Exchange Commission ("SEC") on Form S-3. The Registration
Statement has been declared effective by the SEC. The Registration Statement is
a "universal shelf registration statement." It relates to the possible offering
of Genaissance common stock, preferred stock, debt and/or warrants to purchase
such securities in the future. To proceed with an offering, Genaissance would
need to, among other things, file a prospectus supplement with the SEC
specifying the type of securities to be offered (e.g., common stock) and the
terms and conditions of the offering (e.g., the number of shares to be offered,
the price per share, and whether the offering would be underwritten). You may
view the Registration Statement by accessing our EDGAR filings on the SEC's
website (//www.sec.gov). Genaissance filed the Registration Statement in order
to complete in advance some of the regulatory requirements which must be met
before Genaissance can access the capital markets.

         You are a party to the [Amended and Restated Registration Rights
Agreement] (the "Agreement"), dated as of [March 10, 2000], by and among
Genaissance and certain investors that purchased shares of Genaissance Series
[B/KBH Preferred Stock] in [February and/or March 2000]. The Series [B/KBH
Preferred Stock] was converted into Genaissance common stock in August 2000 in
connection with Genaissance's initial public offering. Shares of common stock
received upon the conversion are considered Restricted Securities under the
Agreement so long as they are held by the original purchasers or by certain
transferees who acquired the shares in private transactions. Our records
indicate that your shares of common stock are considered Restricted Securities
and continue to be covered by the Agreement.

         Section 6 of the Agreement provides holders of Restricted Securities
with certain incidental or "piggy-back" registration rights, which generally
afford holders of Restricted

<PAGE>

[Investor name]
February 18, 2002
Page 2

Securities with the right to include, under certain circumstances, their
Restricted Securities or a portion thereof in certain securities offerings of
Genaissance. Section 12 of the Agreement provides that Genaissance will give you
prior written notice of the filing of certain registration statements by
Genaissance. Section 17 of the Agreement provides, in relevant part, that the
observance of any term of the Agreement may be waived with the written consent
of Genaissance and the holders of a majority of the Restricted Securities.

         Although your Restricted Securities are covered by the Agreement, you
may sell these securities under SEC Rule 144. Rule 144 exempts certain resales
of restricted securities (as defined in the rule) from the registration
requirements of the Securities Act, provided that certain volume, manner of
sale, public information and notice conditions are satisfied, and provided that
at least one year has elapsed from the later of the date of the acquisition of
the securities from the issuer or from an affiliate (as defined in the rule) of
the issuer. Rule 144(k) exempts the resale of restricted securities by persons
who are not (and for the previous three months have not been) affiliates of the
issuer, provided that at least two years have elapsed from the later of the date
of the acquisition of the securities from the issuer or from an affiliate of the
issuer. Affiliate is defined in Rule 144 as any person that, directly or
indirectly, controls, is controlled by, or is under common control with the
issuer of the securities in question.

         Our records indicate that you acquired your Restricted Securities from
Genaissance on [February 17, 2000]. Accordingly, [so long as you are not (and
for the preceding three months have not been) an affiliate of Genaissance, you
may freely resell your Restricted Securities under Rule 144(k). We do not
believe you are (or during the past three months have been) an affiliate of
Genaissance for purposes of Rule 144(k).]

         By this letter, Genaissance is requesting that you waive, and by
signing below you agree to waive:

         o  your right under Section 6 of the Agreement to include, for a period
            of 180 days from the effective date of this waiver, any Restricted
            Securities (that is, any shares of common stock that continue to be
            covered by the Agreement) in any securities offering conducted by
            Genaissance pursuant to the Registration Statement; and

         o  your right to receive prior notice of the filing with the SEC of the
            Registration Statement and any prospectus supplement to the
            Registration Statement.

This waiver of your right to receive prior notice of the filing with the SEC of
any prospectus supplement to the Registration Statement will be effective for a
period of 180 days from the effective date of this waiver.

         We believe the waiver will benefit Genaissance (and you as a
stockholder of Genaissance) by allowing Genaissance to more easily access the
capital markets. We also believe the waiver is appropriate because the
Registration Statement is a universal shelf registration statement and, as such,
is not an appropriate form of registration statement to include

<PAGE>

[Investor name]
February 18, 2002
Page 3

shares held by stockholders. We also believe the waiver will not diminish your
ability to resell your Genaissance stock in the future should you decide to do
so because, as noted above, [we believe you are already free to resell your
Genaissance common stock under Rule 144(k)]. Accordingly, it is our desire that
you consent to this waiver.

         Please confirm your waiver by signing the counterpart original of this
letter in the space provided below, and return it to my attention by facsimile
(203-786-3656) by Friday, February 22, 2002. Please note that Genaissance has
requested, and expects to receive, waivers from the holders of a majority of the
Restricted Securities. This waiver will be effective at the time that
Genaissance receives waivers from the holders of a majority of the Restricted
Securities. If you have any questions, please call Mr. Joseph Keyes at
203-786-3674.

                   [BALANCE OF PAGE LEFT INTENTIONALLY BLANK]

<PAGE>

[Investor name]
February 18, 2002
Page 4

         We thank you in advance for your cooperation and your waiver.

                                         Very truly yours,

                                         GENAISSANCE PHARMACEUTICALS, INC.

                                         By:
                                            ------------------------------------
                                            Gualberto Ruano, M.D., Ph.D.
                                            Chief Executive Officer

The undersigned hereby agrees to the above-described waiver:

-------------------------
Name of Investor

By:
   ----------------------
   Name:
   Title:

Date:
     --------------------

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