EXHIBIT 4.3  REGISTRATION RIGHTS AGREEMENT  REGISTRATION RIGHTS
AGREEMENT (this Agreement), dated as of May 15, 2009, by and
between ARRAY BIOPHARMA INC., a
Delaware corporation (the Company), DEERFIELD
PRIVATE DESIGN FUND, L.P. (Deerfield Design) and DEERFIELD PRIVATE DESIGN INTERNATIONAL, L.P. (Deerfield
Design International and together with Deerfield Design, the Buyer).  WHEREAS:  A.  In connection with the Facility Agreement by
and between the parties hereto of even date herewith (the Facility
Agreement), the Company has agreed, upon the terms and subject to the
conditions contained therein, to issue and sell to the Buyer Warrants in the
amount described in the Facility Agreement, where each of the Warrants is
exercisable into shares of the Companys common stock, par value $0.001 per
share (the Common Stock), upon the terms and conditions and subject to
the limitations and conditions set forth in the Warrants, all subject to the
terms and conditions of the Facility Agreement; and  B. To induce the Buyer to
execute and deliver the Facility Agreement, the Company has agreed to provide
certain registration rights under the Securities Act of 1933, as amended, and
the rules and regulations thereunder, or any similar successor statute
(collectively, the Securities Act), and applicable state securities
laws,  NOW,
THEREFORE, In consideration of the premises and the mutual
covenants contained herein and other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the Company and the
Buyer hereby agree as follows:  1.
DEFINITIONS.  a. As used in this
Agreement, the following terms shall have the following meanings:  (i) Buyer
means the purchaser of Warrants pursuant to the Facility Agreement specified on
the signature page hereof, and any permitted transferee or assignee who
agrees to become bound by the provisions of this Agreement in accordance with Section 10
hereof.  (ii) Filing
Deadline, for each Registration Statement required to be filed hereunder,
shall mean a date that is thirty (30) calendar days following the date the
Warrants are issued.  (iii) Registration
Deadline shall mean the earlier of (i) the date that is ninety (90)
days after the date that the Registration Statement is actually filed or (ii) the
date that is ninety (90) days after the Filing Deadline.  (iv) Warrant(s)
means the warrants issued by the Company pursuant to the Facility Agreement.  (v) Register, Registered,
and Registration refer to a registration effected by preparing and
filing a Registration Statement or Statements in compliance with the Securities
Act and pursuant to Rule 415 under the Securities Act or any successor rule providing
for offering securities on a continuous basis, and the declaration or ordering
of effectiveness of such Registration Statement by the United States Securities
and Exchange Commission (the SEC).


(vi) Registrable
Securities, for a given Registration, means (a) any shares of Common
Stock (the Warrant Shares) issued or issuable upon exercise of or
otherwise pursuant to the Warrants (without giving effect to any limitations on
exercise set forth in the Warrants), (b) any shares of capital stock
issued or issuable as a dividend on or in exchange for or otherwise with
respect to any of the foregoing, (c) any additional shares of Common Stock
issuable in connection with any anti-dilution provisions in the Warrants, (d) any
other warrants or shares of Common Stock issued pursuant to the terms of the
Facility Agreement, the Warrants or this Registration Rights Agreement, and (e) any
securities issued or issuable upon any stock split, dividend or other
distribution, recapitalization or similar event with respect to the foregoing.
Securities will cease to be Registrable Securities when (A) they have been
effectively registered under the Securities Act and disposed of in accordance
with the registration statement covering them; (B) they are transferred
pursuant to Rule 144 or an exemption from registration under the
Securities Act; or (C) they have been otherwise transferred and new
certificates for them not bearing a restrictive legend have been issued by the
Company and the Company shall not have a stop transfer instructions against
them.  (vii) Registration
Statement(s) means a registration statement(s) of the Company under
the Securities Act required to be filed hereunder.  2.
REGISTRATION.  a.
Mandatory Registration.Following the date Warrants
are issued pursuant to the Facility Agreement (the Issuance Date), the
Company shall prepare, and, on or prior to the applicable Filing Deadline file
with the SEC a Registration Statement (the Mandatory Registration Statement)
on Form S-3 (or, if Form S-3 is not then available, on such form of
Registration Statement as is then available to effect a registration of the
Registrable Securities, subject to the consent of the Buyer, which consent will
not be unreasonably withheld) covering the resale of the Registrable Securities
issued on the applicable Issuance Date, which Registration Statement, to the
extent allowable under the Securities Act and the rules and regulations
promulgated thereunder (including Rule 416), shall state that such
Registration Statement also covers such indeterminate number of additional
shares of Common Stock as may become issuable upon exercise of or otherwise
pursuant to the Warrants to prevent dilution resulting from stock splits, stock
dividends or similar transactions. The number of shares of Common Stock
initially included in such Registration Statement shall be no less than the
aggregate number of Warrant Shares that are then issuable upon exercise of or
otherwise pursuant to the Warrants issued on the Issuance Date (as defined
herein), without regard to any limitation on the Buyers ability to exercise
the Warrants, respectively. The Company acknowledges that the number of shares
initially included in the Registration Statement represents a good faith
estimate of the maximum number of shares issuable upon exercise of or otherwise
pursuant to the Warrants issued on the Issuance Date and shall be amended if
not sufficient. The Registration Statement (and each amendment or supplement
thereto, and each request for acceleration of effectiveness thereof) shall be
provided to (and subject to the approval, which shall not be unreasonably
withheld, of) the Buyer and its counsel prior to its filing or other
submission.  b.Piggy-Back Registrations.Subject to the last sentence of this Section 2(b),
if at any time prior to the expiration of the Registration Period (as
hereinafter defined) the Company shall determine to file with the SEC a
Registration Statement relating to an offering for its own account or the
account of others under the Securities Act of any of its equity securities
(other than on Form S-8 or its then equivalent relating to equity
securities to be issued solely in connection with equity securities issuable in
connection with stock option, stock purchase or other employee benefit plans or
a registration statement relating to any acquisition of any entity or business),
the Company shall send to Buyer written notice of such determination and, if
within fifteen (15) days after the effective date of such notice, the Buyer
shall so request in writing, the Company shall include in such Registration
Statement all or any part of the Registrable Securities the Buyer requests to
be registered, except that if, in connection with any  2


underwritten public offering
for the account of the Company, the managing underwriter(s) thereof shall
impose a limitation on the number of Registrable Securities which may be
included in the Registration Statement because, in such underwriter(s)
judgment, marketing or other factors dictate such limitation is necessary to
facilitate public distribution, then the Company shall be obligated to include
in such Registration Statement only such limited portion of the Registrable
Securities with respect to which the Buyer has requested inclusion hereunder as
the underwriter shall permit;  PROVIDED, HOWEVER, that the
Company shall not exclude any Registrable Securities unless the Company has
first excluded all outstanding securities, the holders of which are not
entitled by contract to inclusion of such securities in such Registration
Statement or are not entitled to pro rata inclusion with the Registrable
Securities; and  PROVIDED,
FURTHER, HOWEVER, that, after giving effect to the immediately
preceding proviso, any exclusion of Registrable Securities shall be made pro
rata with holders of other securities having the contractual right to include
such securities in the Registration Statement other than holders of securities
entitled to inclusion of their securities in such Registration Statement by
reason of demand registration rights. No right to registration of Registrable
Securities under this Section 2(b) shall be construed to limit any
registration required under Section 2(a) hereof. If an offering in
connection with which the Buyer is entitled to registration under this Section 2(b) is
an underwritten offering, then the Buyer shall, unless otherwise agreed by the
Company, offer and sell such Registrable Securities in an underwritten offering
using the same underwriter or underwriters and, subject to the provisions of
this Agreement and the underwriting agreement in such offering, on the same
terms and conditions as other shares of Common Stock included in such
underwritten offering (including, without limitation, execution of an agreement
with the managing underwriter or agent limiting the sale or distribution such
Buyer may make of shares of Common Stock or any securities convertible or
exchangeable or exerciseable for such shares of the Company, except as part of
such registration). Notwithstanding anything to the contrary set forth herein,
the registration rights of the Buyer pursuant to this Section 2(b) shall
only be available in the event the Company fails to timely file, obtain
effectiveness or maintain effectiveness of any Registration Statement to be
filed pursuant to Section 2(a) in accordance with the terms of this
Agreement.  2A.  TERMINATION OF PREVIOUS REGISTRATION RIGHTS
AGREEMENT.The parties
agree that the Registration Rights Agreement, dated as of April 29, 2008
among the parties hereto is hereby terminated in all respects.  3.  OBLIGATIONS OF THE COMPANY.In connection
with the registration of the Registrable Securities, the Company shall have the
following obligations:  a. The Company shall prepare
promptly, and file with the SEC as soon as practicable after the Issuance Date
(but no later than the Filing Deadline), a Registration Statement with respect
to the number of Registrable Securities provided in Section 2(a), and
thereafter use its reasonable best efforts to cause each such Registration
Statement relating to Registrable Securities to become effective as soon as
possible after such filing, but in any event shall cause such Registration
Statement relating to Registrable Securities to become effective no later than
the Registration Deadline, and shall keep the Registration Statement current
and effective pursuant to Rule 415 at all times until such date as is the
earlier of (i) the date on which all of the Registrable Securities for
such Registration Statement have been sold and (ii) the date on which all
of the Registrable Securities for such Registration Statement (in the opinion
of counsel to the Buyer) may be immediately sold to the public without
registration or restriction (including without limitation as to volume by each
holder thereof) under the Securities Act (the Registration Period),
which Registration Statement (including any amendments or supplements thereto
and prospectuses contained therein) shall not contain any untrue statement of a
material fact or omit to state a material fact required to be stated therein,
or necessary to make the statements therein not misleading.  3


b. The Company shall prepare
and file with the SEC such amendments (including post-effective amendments) and
supplements to the Registration Statement and the prospectus used in connection
with the Registration Statement as may be necessary to keep the Registration
Statement current and effective at all times during the Registration Period,
and, during such period, comply with the provisions of the Securities Act with
respect to the disposition of all Registrable Securities of the Company covered
by the Registration Statement until such time as all of such Registrable
Securities have been disposed of in accordance with the intended methods of
disposition by the seller or sellers thereof as set forth in the Registration
Statement. In the event that on any Trading Day (as defined below) (the Registration
Trigger Date) the number of shares available under the Registration
Statements filed pursuant to this Agreement is insufficient to cover all of the
Registrable Securities issued or issuable upon exercise of or otherwise
pursuant to the Warrants, without giving effect to any limitations on the Buyer
ability to exercise the Warrants, the Company shall amend the Registration
Statement, or file a new Registration Statement (on the short form available
therefor, if applicable), or both, so as to cover the total number of
Registrable Securities so issued or issuable (without giving effect to any
limitations on exercise contained in the Warrants or limitations on conversion
or exercise) as of the Registration Trigger Date as soon as practicable, but in
any event within thirty (30) days after the Registration Trigger Date, or as
promptly as practicable if the Company is required to increase its authorized
shares (based on the Exercise Price (as defined in the Warrants) of the
Warrants, and other relevant factors on which the Company reasonably elects to
rely). The Company shall use its reasonable best efforts to cause such
amendment and/or new Registration Statement to become effective as soon as
practicable following the filing thereof, but in any event the Company shall
cause such amendment and/or new Registration Statement to become effective
within sixty (60) days of the Registration Trigger Date or as promptly as
practicable in the event the Company is required to increase its authorized
shares.  Trading Day shall mean
any day on which the Common Sock is traded for any period on the NASDAQ Global
Market, or on the principal securities exchange or other securities market on
which the Common Stock is then being traded.  c. The Company shall furnish
to the Buyer and its legal counsel (i) promptly after the same is prepared
and publicly distributed, filed with the SEC, or received by the Company, one
copy of the Registration Statement and any amendment thereto, each preliminary
prospectus and prospectus and each amendment or supplement thereto, and, in the
case of a Registration Statement referred to in Section 2(a), each letter
written by or on behalf of the Company to the SEC or the staff of the SEC, and
each item of correspondence from the SEC or the staff of the SEC, in each case
relating to such Registration Statement (other than any portion of any thereof
which contains information for which the Company has sought confidential
treatment), and (ii) such number of copies of a prospectus, including a
preliminary prospectus, and all amendments and supplements thereto and such
other documents as the Buyer may reasonably request in order to facilitate the
disposition of the Registrable Securities owned by the Buyer. The Company will
immediately notify the Buyer by facsimile of the effectiveness of each
Registration Statement or any post-effective amendment. The Company will
promptly respond to any and all comments received from the SEC, with a view
towards causing each Registration Statement or any amendment thereto to be
declared effective by the SEC as soon as practicable and shall file an
acceleration request as soon as practicable, but no later than three (3) business
days, following the resolution or clearance of all SEC comments or, if
applicable, following notification by the SEC that any such Registration
Statement or any amendment thereto will not be subject to review.  d. The Company shall use
reasonable best efforts to (i) register and qualify the Registrable
Securities covered by the Registration Statements under such other securities
or blue sky laws of such jurisdictions in the United States as the Buyer
shall reasonably request, (ii) prepare and file in those jurisdictions
such amendments (including post-effective amendments) and supplements to such
registrations and qualifications as may be necessary to maintain the
effectiveness thereof during the Registration Period, (iii) take such
other actions as may be necessary to maintain such registrations and  4


qualifications in effect at
all times during the Registration Period, and (iv) take all other actions
reasonably necessary or advisable to qualify the Registrable Securities for
sale in such jurisdictions; PROVIDED, HOWEVER, that the Company shall not be
required in connection therewith or as a condition thereto to (x) qualify
to do business in any jurisdiction where it would not otherwise be required to
qualify but for this Section 3(d), (y) subject itself to general
taxation in any such jurisdiction, or (z) file a general consent to
service of process in any such jurisdiction.  e. As promptly as practicable
after becoming aware of such event, the Company shall notify the Buyer of the
happening of any event, of which the Company has knowledge, as a result of
which the prospectus included in the Registration Statement, as then in effect,
includes an untrue statement of a material fact or omits to state a material
fact required to be stated therein or necessary to make the statements therein
not misleading, and use its reasonable best efforts promptly to prepare a
supplement or amendment to the Registration Statement to correct such untrue
statement or omission, and deliver such number of copies of such supplement or
amendment to the Buyer as the Buyer may reasonably request.  f. The Company shall use its
reasonable best efforts to prevent the issuance of any stop order or other
suspension of effectiveness of the Registration Statement, and, if such an
order is issued, to obtain the withdrawal of such order at the earliest
possible moment and to notify the Buyer who holds Registrable Securities being
sold (or, in the event of an underwritten offering, the managing underwriters)
of the issuance of such order and the resolution thereof.  g. The Company shall permit
a single firm of counsel designated by the Buyer to review such Registration
Statement and all amendments and supplements thereto (as well as all requests
for acceleration or effectiveness thereof), at Buyers own cost, a reasonable
period of time prior to their filing with the SEC (not less than five (5) business
days but not more then eight (8) business days) and not file any document
in a form to which such counsel reasonably objects and will not request
acceleration of such Registration Statement without prior notice to such
counsel.  h. The Company shall hold in
confidence and not make any disclosure of information concerning the Buyer
provided to the Company unless (i) disclosure of such information is
necessary to comply with federal or state securities laws, (ii) the
disclosure of such information is necessary to avoid or correct a misstatement
or omission in any Registration Statement, (iii) the release of such
information is ordered pursuant to a subpoena or other order from a court or
governmental body of competent jurisdiction, or (iv) such information has
been made generally available to the public other than by disclosure in
violation of this or any other agreement. The Company agrees that it shall,
upon learning that disclosure of such information concerning the Buyer is
sought in or by a court or governmental body of competent jurisdiction or
through other means, give prompt notice to the Buyer prior to making such
disclosure, and allow the Buyer, at its expense, to undertake appropriate
action to prevent disclosure of, or to obtain a protective order for, such
information.  i. The Company shall use its
reasonable best efforts to cause all the Registrable Securities covered by the
Registration Statement to be listed on each securities exchange on which
securities of the same class or series issued by the Company are then listed,
if any, if the listing of such Registrable Securities is then permitted under
the rules of such exchange, and, if listed on a national exchange, to
arrange for at least two market makers to register with the National
Association of Securities Dealers, Inc. (NASD) as such with
respect to such Registrable Securities.  j. The Company shall provide
a transfer agent and registrar, which may be a single entity, for the
Registrable Securities not later than the effective date of the Registration
Statement.  5


k. The Company shall
cooperate with the Buyer who holds Registrable Securities being offered and the
managing underwriter or underwriters as reasonably requested by them with
respect to a Registration Statement, if any, to facilitate the timely
preparation and delivery of certificates (not bearing any restrictive legends)
representing Registrable Securities to be offered pursuant to such Registration
Statement and enable such certificates to be in such denominations or amounts,
as the case may be, as the managing underwriter or underwriters, if any, or the
Buyer may reasonably request and registered in such names as the managing
underwriter or underwriters, if any, or the Buyer may request, and, within
three (3) business days after a Registration Statement which includes
Registrable Securities is ordered effective by the SEC, the Company shall
deliver, and shall cause legal counsel selected by the Company to deliver, to
the transfer agent for the Registrable Securities (with copies to the Buyer) an
appropriate instruction and an opinion of such counsel in the form required by
the transfer agent in order to issue the Registrable Securities free of
restrictive legends.  l. At the request of the
Buyer, the Company shall prepare and file with the SEC such amendments
(including post-effective amendments) and supplements to a Registration
Statement and any prospectus used in connection with the Registration Statement
as may be necessary in order to change the plan of distribution set forth in
such Registration Statement.  m. The Company shall not,
and shall not agree to, allow the holders of any securities of the Company to
include any of their securities in a Registration Statement under Section 2(a) hereof
or any amendment or supplement thereto under Section 3(b) hereof
without the consent of the Buyer. In addition, the Company shall not offer any
securities for its own account or the account of others in a Registration
Statement under Section 2(a) hereof or any amendment or supplement
thereto under Section 3(b) hereof without the consent of the Buyer.  n. The Company shall take
all other reasonable actions necessary to expedite and facilitate disposition
by the Buyer of Registrable Securities pursuant to a Registration Statement.  o. The Company shall use
reasonable best efforts to comply with all applicable laws related to a
Registration Statement and offering and sale of securities and all applicable rules and
regulations of governmental authorities in connection therewith (including without
limitation the Securities Act and the Exchange Act and the rules and
regulations promulgated by the SEC).  p. NASD Rule 2710
Filing; Broker Compensation. If required by the National Association of
Securities Dealers, Inc. Corporate Financing Department, the Company shall
promptly effect a filing with the NASD pursuant to NASD Rule 2710 with
respect to the public offering contemplated by resales of securities under the
Registration Statement (an Issuer Filing), and pay the filing fee
required by such Issuer Filing. The Company shall use commercially reasonable
efforts to pursue the Issuer Filing until the NASD issues a letter confirming
that it does not object to the terms of the offering contemplated by the
Registration Statement.  q. Notwithstanding
anything to the contrary herein, at any time after the Registration Statement
has been declared effective by the SEC, the Company may delay or suspend the
effectiveness of any Registration Statement or the use of any prospectus
forming a part of the Registration Statement due to the non-disclosure of
material, non-public information concerning Company the disclosure of which at
the time is not in its best interest, in the good faith opinion of the Company
(a Grace Period); provided, that the Company shall promptly notify the
Buyer in writing of the existence of a Grace Period in conformity with the
provisions of this Section 3(q) and the date on which the Grace
Period will begin (such notice, a Commencement Notice); and, provided
further, that no Grace Period shall exceed 30 days, and such Grace Periods
shall not exceed an aggregate total of 60 days during any 360-day period.
For purposes of determining the length of a Grace Period above, the Grace
Period shall begin on and include the date  6


specified
by the Company in the Commencement Notice and shall end on and include the date
the Buyer receives written notice of the termination of the Grace Period by the
Company (which notice may be contained in the Commencement Notice).  The provisions of Section 3(e) hereof
shall not be applicable during any Grace Period. Upon expiration of the Grace
Period, the Company shall again be bound by Section 3(e) with respect
to the information giving rise thereto unless such material, non-public
information is no longer applicable.  r.  Notwithstanding anything to the contrary
herein, a delay in the effectiveness of a Registration Statement caused solely
by the filing of a request for confidential treatment shall not be deemed a
breach of the Companys obligations set forth herein **and in such event the
Registration Deadline shall be deemed extended to the date that is ten
Business Days after the date the SEC agrees to allow confidential treatment
pursuant to such request or the date such request is withdrawn by the Company,
as applicable**.  4.
OBLIGATIONS OF THE BUYER.In connection with the registration of the
Registrable Securities, the Buyer shall have the following obligations:  a. It shall be a condition
precedent to the obligations of the Company to complete the registration
pursuant to this Agreement with respect to the Registrable Securities of the
Buyer that the Buyer shall furnish to the Company such information regarding
itself, the Registrable Securities held by it and the intended method of
disposition of the Registrable Securities held by it as shall be reasonably
required to effect the registration of such Registrable Securities and shall
execute such documents in connection with such registration as the Company may
reasonably request. At least five (5) business days prior to the first
anticipated filing date of the Registration Statement, the Company shall notify
the Buyer of the information the Company requires from each Buyer.  The Buyer must provide such information to
the Company at least three (3) Business Days prior to the first
anticipated filing date of such Registration Statement if such Buyer elects to
have any Registrable Securities included in the Registration Statement.  b. The Buyer, by the Buyers
acceptance of the Registrable Securities, agrees to cooperate with the Company
as reasonably requested by the Company in connection with the preparation and
filing of a Registration Statement hereunder, unless the Buyer has notified the
Company in writing of the Buyers election to exclude all of the Buyers
Registrable Securities from such Registration Statement.  c. In the event of an
underwritten offering pursuant to Section 2(b) in which any
Registrable Securities are to be included, the Buyer agrees to enter into and
perform the Buyers obligations under an underwriting agreement, in usual and
customary form, including, without limitation, customary indemnification and
contribution obligations, with the managing underwriter of such offering and
take such other actions as are reasonably required in order to expedite or
facilitate the disposition of the Registrable Securities, unless the Buyer has
notified the Company in writing of the Buyers election to exclude all of the
Buyers Registrable Securities from such Registration Statement.  d. The Buyer agrees that,
upon receipt of any notice from the Company of the happening of any event of
the kind described in Section 3(e) or 3(f) or the commencement
of a Grace Period, the Buyer will immediately discontinue disposition of
Registrable Securities pursuant to the Registration Statement covering such
Registrable Securities until the Buyers receipt of the copies of the
supplemented or amended prospectus contemplated by Section 3(e) or 3(f) and,
if so directed by the Company, the Buyer shall deliver to the Company (at the
expense of the Company) or destroy (and deliver to the Company a certificate of
destruction) all copies in the Buyers possession, of the prospectus covering
such Registrable Securities current at the time of receipt of such notice.  e. The Buyer agrees
that it will not effect any disposition or other transfer of the Registrable
Securities that would constitute a sale within the meaning of the Securities
Act other than transactions exempt from  7


the registration
requirements of the Securities Act or pursuant to, and as contemplated in, the
Registration Statement, and that it will promptly notify the Company of any
material changes in the information set forth in the Registration Statement
furnished by or regarding the Buyer or its plan of distribution.  5. REGISTRATION FAILURE.In the event of a Registration Failure (as
defined in the Warrants), the Buyer shall be entitled to Failure Payments (as
defined in the Warrants) and such other rights as set forth in the Warrants.  6. EXPENSES
OF REGISTRATION.All reasonable expenses, other than underwriting
discounts and commissions, incurred in connection with registrations, filings
or qualifications pursuant to Sections 2 and 3, including, without limitation,
all registration, listing and qualification fees, printers and accounting fees,
and the fees and disbursements of counsel for the Company (but not including
fees and disbursements for counsel for the Buyer) shall be borne by the
Company.  7.
INDEMNIFICATION.In the event any Registrable Securities are
included in a Registration Statement under this Agreement, including without
limitation, shares of Common Stock issued pursuant to Section 2.14 of the Facility
Agreement:  a. The Company will
indemnify, hold harmless and defend (i) the Buyer, and (ii) the
directors, officers, partners, managers, members, employees, agents and each
person who controls any Buyer within the meaning of the Securities Act or the
Exchange Act, (iii) any underwriter (as defined in the Securities Act) for
the Buyer in connection with an underwritten offering pursuant to Section 2(b) hereof,
and (iv) the directors, officers, partners, employees and each person who
controls any such underwriter within the meaning of the Securities Act or the
Exchange Act, if any (each, an Indemnified Person), against any joint
or several losses, claims, damages, liabilities or expenses (collectively,
together with actions, proceedings or inquiries by any regulatory or
self-regulatory organization, whether commenced or threatened, in respect
thereof, Claims) to which any of them may become subject insofar as
such Claims arise out of or are based upon: 
(i) any untrue statement or alleged untrue statement of a material
fact in a Registration Statement or the omission or alleged omission to state
therein a material fact required to be stated or necessary to make the
statements therein not misleading; (ii) any untrue statement or alleged
untrue statement of a material fact contained in any preliminary prospectus if
used prior to the effective date of such Registration Statement, or contained
in the final prospectus (as amended or supplemented, if the Company files any
amendment thereof or supplement thereto with the SEC) or the omission or
alleged omission to state therein any material fact necessary to make the
statements made therein, in light of the circumstances under which the
statements therein were made, not misleading; or (iii) any violation or alleged
violation by the Company of the Securities Act, the Exchange Act, any other
law, including, without limitation, any state securities law, or any rule or
regulation thereunder relating to the offer or sale of the Registrable
Securities (the matters in the foregoing clauses (i) through (iii) being,
collectively, Violations).  The
Company shall reimburse the Indemnified Person, promptly as such expenses are
incurred and are due and payable, for any reasonable legal fees or other
reasonable expenses incurred by them in connection with investigating or
defending any such Claim. Notwithstanding anything to the contrary contained
herein, the indemnification agreement contained in this Section 7(a) shall
not apply (A)(i) to a Claim arising out of or based upon a Violation to
the extent that such Violation occurs in reliance upon and in conformity with
information furnished in writing to the Company by any Indemnified Person for
use in connection with the preparation of such Registration Statement or any such
amendment thereof or supplement thereto, or (ii) to the extent due to the
failure of Buyer to timely deliver any prospectus, including any corrected
prospectus, timely made available by the Company pursuant to Section 3(d);
or (B) to any amounts paid in settlement of any Claim effected without the
prior written consent of the Company, which consent shall not be unreasonably
withheld.  Such indemnity shall remain in
full force and effect regardless of any investigation made by or on behalf of
the Indemnified Person and shall survive the transfer of the Registrable
Securities by the Buyer pursuant to Section 10.  8


b. The
Buyer will indemnify, hold harmless and defend (i) the Company, and (ii) the
directors, officers, partners, managers, members, employees, or agents of the
Company, if any (each, a Company Indemnified Person), against any
Claims to which any of them may become subject insofar as such Claims arise out
of or are based upon any Violation which occurs due to the inclusion by the
Company in a Registration Statement of false or misleading information about
the Buyer, where such information was furnished in writing to the Company by
the Buyer expressly for the purpose of inclusion in such Registration
Statement. The Buyer shall reimburse the Company Indemnified Person, promptly
as such expenses are incurred and are due and payable, for any reasonable legal
fees or other reasonable expenses incurred by them in connection with
investigating or defending any such Claim, provided however, that the indemnity
agreement contained in this Section 7(b) and the agreement with
respect to contribution contained in Section 8 shall not apply to amounts
paid in settlement of any Claim if such settlement is effected without the
prior written consent of the Buyer which consent shall not be unreasonably
withheld or delayed; PROVIDED, FURTHER, HOWEVER, that the Buyer shall be liable
under this Section 7(b) for only that amount of a Claim as does not
exceed the net amount of proceeds received by Buyer as a result of the sale of
Registrable Securities pursuant to such Registration Statement. Such indemnity
shall remain in full force and effect regardless of any investigation made by
or on behalf of such Company Indemnified Person. Notwithstanding anything to
the contrary contained herein, the indemnification agreement contained in this Section 7(b) with
respect to any preliminary prospectus shall not inure to the benefit of any
Company Indemnified Person if the untrue statement or omission of material fact
contained in the preliminary prospectus was corrected on a timely basis in the
prospectus, as then amended or supplemented.  c. Promptly
after receipt by a Non-Company Indemnified Person or a Company Indemnified
Person (each an Indemnified Person) under this Section 7 of
notice of the commencement of any action (including any governmental action),
such Indemnified Person shall, if a Claim in respect thereof is to be made
against the Company or the Buyer (each an Indemnifying Person) under
this Section 7, deliver to the Indemnifying Person a written notice of the
commencement thereof enclosing a copy of all relevant documents, including all
papers served and claims made, but the failure to deliver written notice to the
Indemnifying Person within a reasonable time of the commencement of any such
action shall not relieve the Indemnifying Person of any liability to the
Indemnified Person under this Section 7, except to the extent that the
Indemnifying Person is actually prejudiced in its ability to defend such
action. The indemnification required by this Section 7 shall be made by
periodic payments of the amount thereof during the course of the investigation
or defense, as such expense, loss, damage or liability is incurred and is due
and payable.  d. In
the event a Claim is made against an Indemnified Person and it shall notify the
applicable Indemnifying Person of the commencement thereof as provided by Section 7(c),
such Indemnifying Person shall be entitled to participate in, and provided such
Claim is solely for money damages and does not seek an injunction or other
equitable relief against the Indemnified Person and is not a criminal or
regulatory action, to assume the defense of, such Claim with counsel reasonably
satisfactory to such Indemnified Person, and after notice from such
Indemnifying Person to such Indemnified Person of such Indemnifying Persons
election so to assume the defense thereof and the failure by such Indemnified
Person to object to such counsel within ten (10) business days following
its receipt of such notice, such Indemnifying Person shall not be liable to
such Indemnified Person for legal or other expenses related to such Claim
incurred after such notice of election to assume such defense except as
provided below and except for the reasonable costs of investigating, monitoring
or cooperating in such defense subsequently incurred by such Indemnified Person
reasonably necessary in connection with the defense thereof. Such Indemnified
Person shall have the right to employ its counsel in any such Claim, but the
reasonable fees and expenses of such counsel shall be at the expense of such
Indemnified Person unless:  9


(i) the engagement of counsel by such
Indemnified Person at the expense of the applicable Indemnifying Person has
been authorized in writing by such Indemnifying Person;  (ii) such Indemnified Person shall have
reasonably concluded in its good faith (which conclusion shall be determinative
unless a court determines that such conclusion was not reached reasonably and
in good faith) that there is or may be a conflict of interest between the
applicable Indemnifying Person and such Indemnified Person in the conduct of
the defense of such Claim or that there are or may be one or more different or
additional defenses, claims, counterclaims, or causes of action available to
such Indemnified Person (it being agreed that in any case referred to in this
clause (ii) such Indemnifying Person shall not have the right to direct
the defense of such Claim on behalf of the Indemnified Person);  (iii) the applicable Indemnifying Person shall
not have engaged counsel reasonably acceptable to the Indemnified Person, to
assume the defense of such Claim within a reasonable time after notice of the
commencement thereof, provided however, this clause shall not be deemed to
constitute a waiver of any conflict of interest that may arise with respect to
any such counsel); or  (iv) any counsel engaged by the applicable
Indemnifying Person shall fail to timely commence or diligently conduct the
defense of such Claim and such failure has materially prejudiced (or, in the
reasonable judgment of the Indemnified Person, is in danger of materially
prejudicing) the outcome of such Claim;  In
each instance of (i) through (iv) above, the reasonable fees and
expenses of counsel for such Indemnified Person shall be at the expense of such
Indemnifying Person. Only one counsel shall be retained by all Indemnified
Persons with respect to any Claim, unless counsel for any Indemnified Person
reasonably concludes in good faith (which conclusion shall be determinative
unless a court determines that such conclusion was not reached reasonably and
in good faith) that there is or may be a conflict of interest between such
Indemnified Person and one or more other Indemnified Persons in the conduct of
the defense of such Claim or that there are or may be one or more different or
additional defenses, claims, counterclaims, or causes or action available to
such Indemnified Person.  8.
CONTRIBUTION.To the extent any indemnification by the Company or
Buyer is prohibited or limited by law, each of the Company and the Buyer agrees
to make the maximum contribution with respect to any amounts for which it would
otherwise be liable under Section 7 to the fullest extent permitted by
law, based upon a comparative fault standard; PROVIDED, HOWEVER, that (i) no
Person that is guilty of fraudulent misrepresentation (within the meaning Section 11(f) of
the Securities Act) in connection with such sale shall be entitled to
contribution from any Person who was not guilty of fraudulent
misrepresentation; and (ii) contribution by the Buyer of Registrable
Securities shall be limited in amount to the net amount of proceeds received by
the Buyer from the sale of such Registrable Securities pursuant to such
Registration Statement.  9. REPORTS
UNDER THE 1934 ACT.With a view to making available to the Buyer the
benefits of Rule 144 promulgated under the Securities Act or any other
similar rule or regulation of the SEC that may at any time permit the
Buyer to sell securities of the Company to the public without registration the
Company agrees to:  a. make and keep public
information available, as those terms are understood and defined in Rule 144;  b. file with the SEC in a
timely manner all reports and other documents required of the Company under the
Securities Act and the Exchange Act so long as the Company remains subject to
such requirements and the filing of such reports and other documents is
required for the applicable provisions of Rule 144; and  10


c. furnish to the Buyer so
long as the Buyer owns Registrable Securities, promptly upon request, (i) a
written statement by the Company that it has complied with the reporting
requirements of the Securities Act and the Exchange Act as required for
applicable provisions of Rule 144, (ii) a copy of the most recent
annual or quarterly report of the Company and such other reports and documents
so filed by the Company, and (iii) such other information as may be
reasonably requested to permit the Buyers to sell such securities pursuant to Rule 144
without registration.  The Buyer shall at all times
comply with the restrictions on transfer contained in Section 8 of the
Warrant, which provisions are hereby incorporated by reference and made a part
hereof.  10.
ASSIGNMENT OF REGISTRATION RIGHTS.The rights under this
Agreement shall be automatically assignable by the Buyers to any transferee of
all or any portion of the Registrable Securities if: (i) the Buyer agrees
in writing with the transferee or assignee to assign such rights, and a copy of
such agreement is furnished to the Company within a reasonable time after such
assignment, (ii) the Company is, within a reasonable time after such
transfer or assignment, furnished with written notice of (a) the name and
address of such transferee or assignee, and (b) the securities with
respect to which such registration rights are being transferred or assigned,
and (iii) at or before the time the Company receives the written notice
contemplated by clause (ii) of this sentence, the transferee or assignee
agrees in writing with the Company to be bound by all of the provisions
contained herein. In the event that the Buyer transfers all or any portion of
its Registrable Securities pursuant to this Section, the Company shall have at
least ten (10) business days to file any amendments or supplements
necessary to keep the Registration Statement current and effective pursuant to Rule 415,
and the commencement date of any Event of Failure (as defined in the Warrants)
or Event of Default (as defined in the Warrants) under the Warrants caused
thereby will be extended by ten (10) business days.  11.
AMENDMENT OF REGISTRATION RIGHTS; TERMINATION.Provisions of this
Agreement may be amended and the observance thereof may be waived (either
generally or in a particular instance and either retroactively or
prospectively), only with written consent of the Company and the Buyer (to the
extent such Buyer still owns Registrable Securities). Any amendment or waiver
effected in accordance with this Section 11 shall be binding upon the Buyer
and the Company.  12.
MISCELLANEOUS.  a. A person or entity is
deemed to be a holder of Registrable Securities whenever such person or entity
owns of record or beneficially through a street name holder such Registrable
Securities. If the Company receives conflicting instructions, notices or
elections from two or more persons or entities with respect to the same
Registrable Securities, the Company shall act upon the basis of instructions,
notice or election received from the registered owner of such Registrable
Securities.  b. Any notices required or
permitted to be given under the terms hereof shall be sent by certified or
registered mail (return receipt requested) or delivered personally or by
courier (including a recognized overnight delivery service) or by facsimile and
shall be effective five days after being placed in the mail, if mailed by
regular United States mail, or upon receipt, if delivered personally or by
courier (including a recognized overnight delivery service) or by facsimile, in
each case addressed to a party.  The
addresses for such communications shall be:  If to the Company:  Array
BioPharma Inc. 3200
Walnut Street  11


Boulder,
Colorado 80301 Attention:  John R. Moore Vice
President, General Counsel Facsimile:  (303) 386-1290  With
a copy to:  Hogan &
Hartson LLP 1470
Walnut Street, Suite 200 Boulder,
Colorado 80302 Attention:  Carin M. Kutcipal Facsimile:  (702) 406-5301  If to a Buyer:  c/o Deerfield Capital, L.P. 780 Third Avenue, 37thFloor New York, New York 10017 Fax:  (212) 599-1248 Attn:  Alexander Karnal  With a copy to:  Katten Muchin Rosenman LLP 575 Madison Avenue New York, New York 10022 Fax:  (212) 940-8776 Attn:  Mark I. Fisher, Esq. Elliot Press, Esq.  Each party shall provide
notice to the other party of any change in address.  c. Failure of any party to
exercise any right or remedy under this Agreement or otherwise, or delay by a
party in exercising such right or remedy, shall not operate as a waiver
thereof.  d. Governing Law. All
questions concerning the construction, validity, enforcement and interpretation
of this Agreement shall be governed by and construed and enforced in accordance
with the internal laws of the State of New York, without regard to the principles
of conflicts of law thereof. Each party agrees that all legal proceedings
concerning the interpretations, enforcement and defense of the transactions
contemplated by this Agreement (whether brought against a party hereto or its
respective affiliates, directors, officers, shareholders, employees or agents)
shall be commenced exclusively in the state and federal courts sitting in the
City of New York. Each party hereby irrevocably submits to the exclusive
jurisdiction of the state and federal courts sitting in the City of New York,
borough of Manhattan for the adjudication of any dispute hereunder or in
connection herewith or with any transaction contemplated hereby or discussed
herein, and hereby irrevocably waives, and agrees not to assert in any suit,
action or proceeding, any claim that it is not personally subject to the
jurisdiction of any such court, that such suit, action or proceeding is
improper or is an inconvenient venue for such proceeding. Each party hereby
irrevocably waives personal service of process and consents to process being
served in any such suit, action or proceeding by mailing a copy thereof via
registered or certified mail or overnight delivery (with evidence of delivery)
to such party at the address in effect for notices to it under this Agreement
and agrees that such service shall constitute good and sufficient service of
process and notice thereof. Nothing  12


contained herein shall be
deemed to limit in any way any right to serve process in any other manner
permitted by law. The parties hereby waive all rights to a trial by jury. If
either party shall commence an action or proceeding to enforce any provision of
this Agreement, then the prevailing party in such action or proceeding shall be
reimbursed by the other party for its reasonable attorneys fees and other
costs and expenses incurred with the investigation, preparation and prosecution
of such action or proceeding.  e. This Agreement, the
Warrants and the Facility Agreement (including all schedules and exhibits
thereto) constitute the entire agreement among the parties hereto with respect
to the subject matter hereof and thereof. There are no restrictions, promises,
warranties or undertakings, other than those set forth or referred to herein
and therein. This Agreement, the Warrants and the Facility Agreement supersede
all prior agreements and understandings among the parties hereto with respect
to the subject matter hereof and thereof.  f. Subject to the
requirements of Section 10 hereof, this Agreement shall inure to the
benefit of and be binding upon the successors and assigns of each of the
parties hereto.  g. The headings in this
Agreement are for convenience of reference only and shall not limit or
otherwise affect the meaning hereof.  h. This Agreement may be
executed in two or more counterparts, each of which shall be deemed an original
but all of which shall constitute one and the same agreement. This Agreement,
once executed by a party, may be delivered to the other party hereto by
facsimile transmission of a copy of this Agreement bearing the signature of the
party so delivering this Agreement.  i. Each party shall do and
perform, or cause to be done and performed, all such further acts and things,
and shall execute and deliver all such other agreements, certificates,
instruments and documents, as the other party may reasonably request in order
to carry out the intent and accomplish the purposes of this Agreement and the
consummation of the transactions contemplated hereby.  j. The Company acknowledges
that a breach by it of its obligations hereunder will cause irreparable harm to
the Buyer by vitiating the intent and purpose of the transactions contemplated
hereby. Accordingly, the Company acknowledges that the remedy at law for breach
of its obligations hereunder will be inadequate and agrees, in the event of a
breach or threatened breach by the Company of any of the provisions hereunder,
that the Buyer shall be entitled, in addition to all other available remedies
in law or in equity, to an injunction or injunctions to prevent or cure
breaches of the provisions of this Agreement and to enforce specifically the
terms and provisions hereof, without the necessity of showing economic loss and
without any bond or other security being required.  k. The language used in this
Agreement will be deemed to be the language chosen by the parties to express
their mutual intent, and no rules of strict construction will be applied
against any party.  l. In the event that any
provision of this Agreement is invalid or unenforceable under any applicable
statute or rule of law, then such provision shall be deemed inoperative to
the extent that it may conflict therewith and shall be deemed modified to
conform with such statute or rule of law. Any provision hereof which may
prove invalid or unenforceable under any law shall not affect the validity or
enforceability of any other provision hereof.  m. In the event a Buyer
shall sell or otherwise transfer any of such holders Registrable Securities,
each transferee shall be allocated a pro rata portion of the number of
Registrable Securities included in a Registration Statement for such
transferor.  13


n. There shall be no oral
modifications or amendments to this Agreement. This Agreement may be modified
or amended only in writing.  [Remainder of page left intentionally blank]  [Signature page follows]  14


IN WITNESS WHEREOF, the
undersigned Buyer and the Company have caused this Agreement to be duly
executed as of the          day of May,
2009.   COMPANY:
  
  BUYER:ARRAY
  BIOPHARMA INC.
  
  DEERFIELD PRIVATE DESIGN
  FUND, L.P.By:
  /s/ R. Michael Carruthers
  
  By:
  /s/ James FlynnName: R. Michael Carruthers
  
  
  Name:
  James FlynnTitle: Chief Financial
  Officer
  
  
  Title:
  General PartnerDEERFIELD PRIVATE DESIGN
  INTERNATIONAL, L.P.By:
  /s/ James FlynnName:
  James FlynnTitle:
  General Partner