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                                                                     Exhibit 4.2

                             REGISTRATION RIGHTS AGREEMENT

      This Registration Rights Agreement is made and entered into as of May 7,
2001 between Cephalon, Inc., a Delaware corporation (the "Company"), and
Robertson Stephens, Inc., Adams, Harkness & Hill, Inc., Banc of America
Securities LLC, CIBC World Markets Corp., SG Cowen Securities Corporation, UBS
Warburg LLC, U.S. Bancorp Piper Jaffray Inc. (the "Purchasers") who have
purchased or have the right to purchase up to $300,000,000 in aggregate
principal amount of 5-1/4% Convertible Subordinated Notes due 2006 (or up to
$400,000,000 if the option set forth in Section 2(b) of the Purchase Agreement
(as defined below) is exercised in full by the Purchasers) of the Company
pursuant to the Purchase Agreement and each Holder (as defined below) by
participating in a Registration Statement agrees to be bound by this Agreement.

      This Agreement is made pursuant to the Purchase Agreement, dated May 2,
2001 among the Company and the Purchasers (the "Purchase Agreement"). In order
to induce the Purchasers to enter into the Purchase Agreement, the Company has
agreed to provide the registration rights provided for in this Agreement to the
Purchasers and their respective direct and indirect transferees (i) for the
benefit of the Purchasers, (ii) for the benefit of the holders from time to time
of the Notes (as such term is defined in Section 1 hereof) (including the
Purchasers) and the holders from time to time of the Common Stock (as such term
is defined in Section 1 hereof) issuable or issued upon conversion of the Notes
and (iii) for the benefit of the securities constituting the Transfer Restricted
Securities (as such term is defined in Section 1 hereof). The execution of this
Agreement is a condition to the closing of the transactions contemplated by the
Purchase Agreement.

      The parties hereby agree as follows:

      1.    Definitions. As used in this Agreement, the following terms shall
have the following meanings:

            Act: As defined in the last paragraph of this Section 1.

            Advice: As defined in Section 2(d) hereof.

            Affiliate: An affiliate of any specified person shall mean any other
person directly or indirectly controlling or controlled by or under direct or
indirect common control with such specified person. For the purposes of this
definition, "control," when used with respect to any person, means the power to
direct the management and policies of such person, directly or indirectly,
whether through the ownership of voting securities, by contract or otherwise and
the terms "affiliated," "controlling" and "controlled" have meanings correlative
to the foregoing.

            Agreement: This Registration Rights Agreement, as the same may be
amended, supplemented or modified from time to time in accordance with the terms
hereof.
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            Business Day: Each Monday, Tuesday, Wednesday, Thursday and Friday
that is not a day on which banking institutions in New York, New York are
authorized or obligated by law or executive order to close.

            Closing Date: May 7, 2001.

            Common Stock: Common Stock, $.01 par value per share, of the Company
and any other shares of common stock as may constitute "Common Stock" for
purposes of the Indenture, in each case, as issuable or issued upon conversion
of the Notes.

            Company: Cephalon, Inc., a Delaware corporation, and any successor
corporation thereto.

            Company Indemnified Person: As defined in Section 6(c) hereof.

            Controlling person: As defined in Section 6(a) hereof.

            Damages Payment Date: Each of the semi-annual interest payment dates
provided in the Indenture.

            Effectiveness Period: As defined in Section 2(a) hereof.

            Effectiveness Target Date: The 180th day following the Closing Date.

            Exchange Act: The Securities Exchange Act of 1934, as amended, and
the rules and regulations promulgated by the SEC thereunder.

            Filing Date: The 45th day after the Closing Date.

            Holder: Each owner of any Transfer Restricted Securities.

            Indemnified Person: As defined in Section 6(a) hereof.

            Indemnified Party: As defined in Section 6(c) hereof.

            Indemnifying Party: The Company, on one hand or any Holder (or
predecessor Holder), on the other hand, as applicable in accordance with Section
6 hereof.

            Indenture: The Indenture, dated as of the date hereof, between the
Company and the Trustee, pursuant to which the Notes are being issued, as the
same may be amended, modified or supplemented from time to time in accordance
with the terms thereof.

            Liquidated Damages: As defined in Section 3(a) hereof.


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            Notes: The $300,000,000 aggregate principal amount of 5-1/4%
Convertible Subordinated Notes due 2006 of the Company being issued pursuant to
the Indenture (or $400,000,000 if the option set forth in Section 2(b) of the
Purchase Agreement is exercised in full by the Initial Purchasers).

            Notice and Questionnaire: A written notice completed by the Holder
and delivered to the Company containing substantially the information called for
by the Selling Securityholder Notice and Questionnaire attached as Annex A to
the Offering Circular of the Company dated May 2, 2001 relating to the Notes.

            Proceeding: An action, claim, suit or proceeding (including, without
limitation, an investigation or partial proceeding, such as a deposition),
whether commenced or threatened.

            Prospectus: The prospectus included in any Registration Statement,
as amended or supplemented by any prospectus supplement, with respect to the
resale of any of the Transfer Restricted Securities covered by such Registration
Statement, and all other amendments and supplements to any such prospectus,
including post-effective amendments, and all materials incorporated by reference
or deemed to be incorporated by reference, if any, in such prospectus.

            Purchase Agreement: As defined in the second paragraph hereof.

            Purchasers: As defined in the first paragraph hereof.

            Record Holder: (i) with respect to any Damages Payment Date relating
to any Note as to which any such Liquidated Damages have accrued, the registered
Holder of such Note on the record date with respect to the interest payment date
under the Indenture on which such Damages Payment Date shall occur and (ii) with
respect to any Damages Payment Date relating to any shares of Common Stock as to
which any such Liquidated Damages have accrued, the registered Holder of such
shares 15 days prior to the next succeeding Damages Payment Date.

            Registration Default: As defined in Section 3(a) hereof.

            Registration Statement: Any registration statement of the Company
filed with the SEC pursuant to the Securities Act that covers the resale of any
of the Transfer Restricted Securities pursuant to the provisions of this
Agreement, including the Prospectus, amendments and supplements to such
registration statement or Prospectus, including pre- and post-effective
amendments, all exhibits thereto, and all material incorporated by reference or
deemed to be incorporated by reference, if any, in such registration statement.

            Requisite Information: As defined in Section 2(c) hereof.

            Restricted Notes: Notes required pursuant to the Indenture to bear
the legend set forth in Section 2.5(d) of the Indenture.


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            Rule 144: Rule 144 promulgated by the SEC pursuant to the Securities
Act, as such rule may be amended from time to time, or any successor rule or
regulation.

            Rule 144A: Rule 144A promulgated by the SEC pursuant to the
Securities Act, as such rule may be amended from time to time, or any successor
rule or regulation.

            Rule 415: Rule 415 promulgated by the SEC pursuant to the Securities
Act, as such rule may be amended from time to time, or any successor rule or
regulation.

            Rule 424: Rule 424 promulgated by the SEC pursuant to the Securities
Act, as such rule may be amended from time to time, or any successor rule or
regulation.

            SEC: The Securities and Exchange Commission.

            Securities Act: The Securities Act of 1933, as amended, and the
rules and regulations promulgated by the SEC thereunder.

            Shelf Registration Statement: As defined in Section 2(a) hereof.

            Special Counsel: The special counsel to the Holders.

            TIA: The Trust Indenture Act of 1939, as amended, and the rules and
regulations promulgated by the SEC thereunder.

            Transfer Restricted Securities: The Restricted Notes and the shares
of Common Stock into which such Restricted Notes are converted or convertible
(including any shares of Common Stock issued or issuable thereon upon any stock
split, stock combination, stock dividend or the like) upon original issuance
thereof, and at all times subsequent thereto, and associated related rights, if
any, until, in the case of any such Restricted Note or shares of Common Stock
(and associated rights) (i) the date on which the resale thereof has been
effectively registered under the Securities Act and disposed of in accordance
with the Registration Statement relating thereto, (ii) the date on which such
security has been distributed to the public pursuant to Rule 144 or is saleable
pursuant to paragraph (k) of Rule 144 or (iii) the date on which such security
ceases to be outstanding, whichever date is earliest.

            Trustee: The trustee under the Indenture.

            underwritten registration or underwritten offering: A registration
in connection with which securities of the Company are sold to one or more
underwriters for reoffering to the public pursuant to an effective Registration
Statement and an executed underwriting agreement.

            References herein to the term "Holders of a majority in aggregate
principal amount of Transfer Restricted Securities" or words to a similar effect
shall mean, with respect to any request, notice, demand, objection or other
action by the Holders hereunder or pursuant hereto (each, an "Act"), registered
Holders of a number of shares of then-outstanding Common Stock constituting


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Transfer Restricted Securities and an aggregate principal amount of then
outstanding Notes constituting Transfer Restricted Securities, such that the sum
of such shares of Common Stock and the shares of Common Stock issuable upon
conversion of such Notes constitutes in excess of 50% of the sum of all of the
then-outstanding shares of Common Stock constituting Transfer Restricted
Securities and the number of shares of Common Stock issuable upon conversion of
then-outstanding Notes constituting Transfer Restricted Securities. For purposes
of the preceding sentence, Transfer Restricted Securities owned, directly or
indirectly, by the Company or its Affiliates shall be deemed not to be
outstanding.

      2.    Shelf Registration Statement

            (a)   The Company agrees to file with the SEC as soon as reasonably
practicable after the Closing Date, but in no event later than the Filing Date,
a Registration Statement for an offering to be made on a continuous basis
pursuant to Rule 415, covering all of the Transfer Restricted Securities or
separate Registration Statements for an offering to be made on a continuous
basis pursuant to Rule 415 covering all of the Notes constituting Transfer
Restricted Securities and all of the Common Stock constituting Transfer
Restricted Securities, respectively (such Registration Statement or Statements,
collectively, the "Shelf Registration Statement"). The Shelf Registration
Statement shall be on Form S-3 under the Securities Act or another appropriate
form selected by the Company permitting registration of such Transfer Restricted
Securities for resale by the Holders in the manner or manners reasonably
designated by Holders of a majority in aggregate principal amount of Transfer
Restricted Securities being sold (including, without limitation, up to three
underwritten offerings). The Company shall not permit any securities other than
the Transfer Restricted Securities to be included in the Shelf Registration
Statement. The Company shall use its reasonable best efforts to cause the Shelf
Registration Statement to be declared effective pursuant to the Securities Act
as soon as reasonably practicable following the filing thereof and to keep the
Shelf Registration Statement continuously effective under the Securities Act for
two years after the latest date of original issuance of any of the Notes
(subject to extension pursuant to Sections 2(d) hereof) (the "Effectiveness
Period"), or such shorter period ending when there cease to be any Transfer
Restricted Securities outstanding.

            (b)   Supplements and Amendments. The Company shall use its
reasonable best efforts to keep the Shelf Registration Statement continuously
effective by supplementing and amending the Shelf Registration Statement if
required by the rules, regulations or instructions applicable to the
registration form used for the Shelf Registration Statement, if required by the
Securities Act or if reasonably requested by the Holders of a majority in
aggregate principal amount of the Transfer Restricted Securities or by any
underwriter of such Transfer Restricted Securities; provided, however, that the
Effectiveness Period shall be extended as provided in Section 2(d) hereof.

            (c)   Selling Securityholder Information. Each Holder of Transfer
Restricted Securities agrees that if such Holder wishes to sell Transfer
Restricted Securities pursuant to the Shelf Registration Statement and related
Prospectus, it will do so only in accordance with this


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Section 2. Each Holder of Transfer Restricted Securities wishing to sell
Transfer Restricted Securities pursuant to the Shelf Registration Statement and
related Prospectus agrees to deliver a Notice and Questionnaire that includes
such information regarding the distribution of its Transfer Restricted
Securities as is required by law to be disclosed by the Holder in the Shelf
Registration Statement (the "Requisite Information") to the Company prior to any
intended distribution of Transfer Restricted Securities under the Shelf
Registration Statement. From and after the date the Shelf Registration Statement
becomes effective, the Company shall, as promptly as is practicable after the
date a Notice and Questionnaire is delivered, and in any event within five (5)
Business Days after such date, (i) if required by applicable law, file with the
SEC a post-effective amendment to the Shelf Registration Statement or prepare
and, if required by applicable law, file a supplement to the related Prospectus
or a supplement or amendment to any document incorporated therein by reference
or file any other required document so that the Holder delivering such Notice
and Questionnaire is named as a selling securityholder in the Shelf Registration
Statement and the related Prospectus in such a manner as to permit such Holder
to deliver such Prospectus to purchasers of the Transfer Restricted Securities
in accordance with applicable law and, if the Company shall file a
post-effective amendment to the Shelf Registration Statement, use its reasonable
best efforts to cause such post-effective amendment to be declared effective
under the Securities Act as promptly as is practicable, (ii) provide such Holder
copies of any documents filed pursuant to Section 2(c)(i); and (iii) notify such
Holder as promptly as practicable after the effectiveness under the Securities
Act of any post-effective amendment filed pursuant to Section 2(c)(i); provided,
that if such Notice and Questionnaire is delivered during a time that the use of
the Prospectus is suspended pursuant to Section 2(d), the Company shall so
inform the Holder delivering such Notice and Questionnaire and shall take the
actions set forth in clauses (i), (ii) and (iii) above upon such time the use of
the Prospectus may be resumed.

            If any such Registration Statement refers to any Holder by name or
otherwise as the holder of any securities of the Company, then such Holder shall
have the right to require, in the event that such reference to such Holder by
name or otherwise is not required by the Securities Act or any similar Federal
statute then in force, the deletion of the reference to such Holder in such
Registration Statement.

            (d)   Certain Notices; Suspension of Sales. Each Holder agrees by
acquisition of such Transfer Restricted Securities that, upon receipt of any
notice from the Company of the happening of any event of the kind described in
Sections 4(c)(ii), 4(c)(iii), 4(c)(v) or 4(c)(vi) hereof, such Holder will
forthwith discontinue disposition of such Transfer Restricted Securities covered
by the Registration Statement and Prospectus (other than in transactions exempt
from the registration requirements under the Securities Act) until such Holder's
receipt of the copies of the supplemented or amended Prospectus contemplated by
Sections 4(c)(i) and 4(k) hereof, or until it is advised in writing (the
"Advice") by the Company that the use of the applicable Prospectus may be
resumed, and, in either case, has received copies of any additional or
supplemental filings that are incorporated or deemed to be incorporated by
reference in such Prospectus. If the Company shall give any such notice, the
Effectiveness Period shall be extended by the number of days during such period
from and including the date of the giving of such notice to and including the
date when each Holder shall


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have received (x) the copies of the supplemented or amended Prospectus
contemplated by Sections 4(c)(i) and 4(k) hereof or (y) the Advice, and, in
either case, has received copies of any additional or supplemental filings that
are incorporated or deemed to be incorporated by reference in such Prospectus.

            (e)   Material Events; Suspension of Sales. Notwithstanding the
provisions contained in this Section 2, in the event that, in the judgment of
the Company's Board of Directors, it is advisable to suspend use of the
Prospectus due to pending corporate developments, public filings with the SEC or
similar events, the Company shall promptly deliver a written certificate to each
registered Holder, the Special Counsel and the managing underwriters, if any, to
the effect that the use of the Prospectus is to be suspended until the Company
shall deliver a written notice that the use of the Prospectus may be resumed.
Thereafter, the use of the Prospectus shall be suspended, and the Company shall
not be required to maintain the effectiveness of, or amend or update the Shelf
Registration Statement, or amend or supplement the Prospectus; provided,
however, that the Company shall only be permitted to suspend the use of the
Prospectus for a period not to exceed 30 days in any six-month period or two
periods not to exceed an aggregate of 60 days in any 12-month period. The
Company will use its best efforts to ensure that the use of the Prospectus may
be resumed as soon as, in the judgment of the Company's Board of Directors,
disclosure of the material relating to such pending development, filing or event
would not have a materially adverse effect on the Company. If the Company shall
give any such suspension notice pursuant to this Section 2(e), the Effectiveness
Period shall be extended by the number of days during such period from and
including the date of giving such notice to and including the date when each
Holder shall have received notice that use of the Prospectus may be resumed.

      3.    Liquidated Damages

            (a)   The Company and the Purchasers agree that the Holders will
suffer damages if the Company fails to fulfill its obligations pursuant to
Section 2 hereof and that it would not be possible to ascertain the extent of
such damages. Accordingly, the Company hereby agrees to pay liquidated damages
("Liquidated Damages") under the circumstances and to the extent set forth
below:

                  (i)   to each Holder if the Shelf Registration Statement has
            not been filed with the SEC on or prior to the Filing Date; or

                  (ii)  to each Holder if the Shelf Registration Statement is
            not declared effective by the SEC on or prior to the applicable
            Effectiveness Target Date; or

                  (iii) to each Holder if the Shelf Registration Statement
            ceases to be effective or usable at any time during the
            Effectiveness Period (without being succeeded on the same day
            immediately by a post-effective amendment or supplement to the Shelf
            Registration Statement that cures such failure and that is itself,
            in the case of post-effective amendment, immediately declared
            effective) for a period of time which shall exceed 90 days in the
            aggregate in any period of 365 consecutive days.


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(any of the foregoing, a "Registration Default"); provided that if a Shelf
Registration Statement is not usable by a particular Holder at any given time
solely as a result of the failure of such Holder to provide Requisite
Information with respect to it, a Registration Default under clause (iii) above
shall not be deemed to have occurred unless such Holder shall have provided such
information to the Company and the Company shall have failed to file an
appropriate Prospectus supplement or post-effective amendment to the Shelf
Registration Statement. In the event of any such Registration Default, the
Company shall accrue Liquidated Damages to each applicable Holder during the
first 90-day period immediately in an amount equal to $.05 per week per $1,000
principal amount of Notes held by such Holder and, if applicable, on an
equivalent basis per share (subject to adjustment in the event of any stock
split, stock combination, stock dividends and the like) of Common Stock
constituting Transfer Restricted Securities held by such Holder for each week or
portion thereof that the Registration Default continues. The weekly rate at
which such Liquidated Damages accrue shall increase by an additional $.05 per
$1,000 principal amount of Notes and, if applicable, an equivalent amount per
week per share (subject to adjustment as set forth above) of Common Stock
constituting Transfer Restricted Securities for each subsequent continuing
90-day period following the occurrence of such Registration Default until all
Registration Defaults have been cured; provided, however, that Liquidated
Damages shall not at any time exceed $.25 per week per $1,000 principal amount
of Notes or, as applicable, an equivalent amount per week per share (subject to
adjustment as set forth above) of Common Stock constituting Transfer Restricted
Securities. In no event shall the Company be required to pay Liquidated Damages
in excess of the applicable maximum weekly amount, regardless of whether one or
multiple Registration Defaults shall exist. Following the cure of all
Registration Defaults, the accrual of Liquidated Damages shall cease (without in
any way limiting the effect of any subsequent Registration Default). A
Registration Default under clause (i) above shall be cured on the date that the
applicable Shelf Registration Statement is filed with the SEC; a Registration
Default under clause (ii) above shall be cured on the date that the applicable
Shelf Registration Statement is declared effective by the SEC; a Registration
Default under clause (iii) above shall be cured on the date the applicable Shelf
Registration Statement is declared effective or otherwise usable; and a
Registration Default under clause (iv) above shall be cured on the date the
applicable prospectus supplement to the Shelf Registration Statement is filed or
the post-effective amendment with respect to such Shelf Registration Statement
is declared effective.

            (b)   The Company shall notify the Trustee within one Business Day
after each and every date on which a Registration Default first occurs.
Liquidated Damages shall be paid by the Company to the Record Holders on each
Damages Payment Date in the same manner as interest is paid under the Indenture,
in the case of the Notes, and by mailing checks to their registered addresses in
the register of the Company for the Common Stock, in the case of shares of
Common Stock; provided, however, that any Liquidated Damages accrued with
respect to any Note or portion thereof called for redemption on a redemption
date, repurchased in connection with a Repurchase Event (as defined in the
Indenture) on a repurchase date, or converted into shares of Common Stock on a
conversion date prior to the Damages Payment Date, shall, in any such event, be
paid instead to the Holder who submitted such Note or portion thereof for
redemption, repurchase or conversion on the applicable redemption date,
repurchase date or conversion date, as the case may be, on such date (promptly
following the conversion date, in the case of conversion of a Note).


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            (c)   All of the Company's obligations set forth in this Section 3
which are unsatisfied to any extent with respect to any Transfer Restricted
Securities at the time such security ceases to be a Transfer Restricted Security
shall survive until such time as all such obligations with respect to such
security have been satisfied in full (notwithstanding the earlier termination of
this Agreement).

            (d)   Any payments due and payable pursuant to this Section 3 with
respect to any Notes shall be subject to the provisions of Article IV of the
Indenture as if such payments were additional interest on the Notes.

      4.    Registration Procedures. In connection with the Company's
registration obligations hereunder, the Company shall effect such registrations
on the appropriate form selected by the Company to permit the resale of Transfer
Restricted Securities in accordance with the intended method or methods of
disposition thereof, and pursuant thereto the Company shall as expeditiously as
reasonably possible:

            (a)   No fewer than five Business Days prior to the initial filing
of a Registration Statement or Prospectus and no fewer than two Business Days
prior to the filing of any amendment or supplement thereto, furnish to the
registered Holders (determined as of the most recent reasonably practicable date
which shall not be more than two Business Days prior to the date such document
is personally delivered, delivered to a next-day courier, deposited in the mail
or telecopied, as the case may be), Special Counsel and the managing
underwriters, if any, copies of all such documents proposed to be filed
(excluding, unless requested, those incorporated or deemed to be incorporated by
reference and then only to the Holder who so requested) and cause the officers
and directors of the Company, counsel to the Company and independent certified
public accountants to the Company to respond to such inquiries as shall be
necessary in connection with such Registration Statement, in the opinion of
Special Counsel and counsel to such underwriters, to conduct a reasonable
investigation within the meaning of the Securities Act. The Company shall not
file any such Registration Statement or related Prospectus or any amendments or
supplements thereto to which the Holders of a majority in aggregate principal
amount of the Transfer Restricted Securities, Special Counsel, or the managing
underwriters, if any, shall reasonably object on a timely basis;

            (b)   Prepare and file with the SEC such amendments, including
post-effective amendments, to each Registration Statement as may be necessary to
keep such Registration Statement continuously effective for the applicable time
period set forth in Section 2(a) hereof in case of the Shelf Registration
Statement and in case of any underwritten offering the period of distribution of
Transfer Restricted Securities covered by such Registration Statement; cause the
related Prospectus to be supplemented by any required Prospectus supplement, and
as so supplemented to be filed pursuant to Rule 424 under the Securities Act
with respect to the disposition of all securities covered by such Registration
Statement during such period in accordance with the intended method or methods
of disposition by the Holder set forth in such Registration Statement as so
amended or in such Prospectus as so supplemented (including, without limitation,
the filing of any Prospectus supplement pursuant to Rule 424 in order to add or
change any selling


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security holder information (including any such supplements or amendments
pursuant to Section 2(c) hereof, provided such Holder to which such change
applies complies with the Requisite Information requirements of Section 2(c)
hereof));

            (c)   Notify the registered (as of the most recent reasonably
practicable date which shall not be more than two Business Days prior to the
date such notice is personally delivered, delivered to a next-day courier,
deposited in the mail or telecopied, as the case may be) Holders, Special
Counsel and the managing underwriters, if any, promptly (and in the case of an
event specified by clause (i)(A) of this paragraph in no event fewer than two
Business Days prior to such filing), and (if requested by any such person),
confirm such notice in writing, (i)(A) when a Prospectus or any Prospectus
supplement or post-effective amendment is proposed to be filed, and, (B) with
respect to a Registration Statement or any post-effective amendment, when the
same has become effective, (ii) of any request of the SEC or any other Federal
or state governmental authority for amendments or supplements to such
Registration Statement or related Prospectus or for additional information
related thereto, (iii) of the issuance by the SEC, any state securities
commission, any other governmental agency or any court of any stop order, order
or injunction suspending or enjoining the use or the effectiveness of the
Registration Statement or the initiation of any proceedings for that purpose,
(iv) if at any time any of the representations and warranties of the Company
contained in any agreement (including any underwriting agreement) contemplated
by Section 4(m) hereof are not true and correct in all material respects during
the effectiveness of such agreement, (v) of the receipt by the Company of any
notification with respect to the suspension of the qualification or exemption
from qualification of any of the Transfer Restricted Securities for sale in any
jurisdiction, or the initiation or threatening of any proceeding for such
purpose, and (vi) of the existence of any fact and the happening of any event
that makes any statement made in such Registration Statement or related
Prospectus untrue in any material respect, or that requires the making of any
changes in such Registration Statement or Prospectus so that in the case of the
Registration Statement, it will not contain any untrue statement of a material
fact or omit to state any material fact required to be stated therein or
necessary to make the statements therein not misleading and that, in the case of
the Prospectus, such Prospectus will not contain any untrue statement of a
material fact or omit to state any material fact required to be stated therein
or necessary to make the statements therein, in light of the circumstances under
which they were made, not misleading;

            (d)   Use its reasonable best efforts to avoid the issuance of, or,
if issued, obtain the withdrawal of any stop order or order enjoining or
suspending the use or effectiveness of a Registration Statement or the lifting
of any suspension of the qualification (or exemption from qualification) of any
of the Transfer Restricted Securities for sale in any jurisdiction, at the
earliest practicable moment;

            (e)   If requested by the Special Counsel, the managing
underwriters, if any, or the Holders of a majority in aggregate principal amount
of the Transfer Restricted Securities being sold in connection with such
offering, (i) promptly include in a Prospectus supplement or post-effective
amendment such information as the Special Counsel, the managing underwriters, if
any, and such Holders agree should, in their reasonable judgment, be included
therein, and (ii) make all required


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<PAGE>   11
filings of such Prospectus supplement or such post-effective amendment as soon
as reasonably practicable after the Company has received notification of the
matters to be included in such Prospectus supplement or post-effective
amendment; provided, however, that the Company shall not be required to take any
action pursuant to this Section 4(e) that would, in the opinion of counsel for
the Company, violate applicable law or which is not reasonably required to
comply with applicable securities laws;

            (f)   Furnish to each Holder who so requests, Special Counsel and
each managing underwriter, if any, without charge, at least one conformed copy
of each Registration Statement and each amendment thereto, including financial
statements (but excluding schedules, all documents incorporated or deemed to be
incorporated therein by reference and all exhibits, unless requested in writing
by such Holder, Special Counsel or managing underwriter);

            (g)   Deliver to each Holder, the Special Counsel, and the
underwriters, if any, without charge, as many copies of the Prospectus or
Prospectuses (including each form of Prospectus) and each amendment or
supplement thereto as such persons may reasonably request; and, unless the
Company shall have given notice to such Holder pursuant to Section 4(c), the
Company hereby consents to the use of such Prospectus and each amendment or
supplement thereto by each of the selling Holders of Transfer Restricted
Securities and the underwriters, if any, in connection with the offering and
sale of the Transfer Restricted Securities covered by such Prospectus and any
amendment or supplement thereto, provided, however, that no Holder shall be
entitled to use the Prospectus unless and until such Holder shall have furnished
to the Company any and all Requisite Information pursuant to Section 2(c)
hereof;

            (h)   Use its reasonable best efforts to register or qualify, or
cooperate with the Holders of Transfer Restricted Securities to be sold or
tendered for, the underwriters, if any, and their respective counsel in
connection with the registration or qualification (or exemption from such
registration or qualification) of, such Transfer Restricted Securities for offer
and sale under the securities or Blue Sky laws of such jurisdictions within the
United States as any Holder or underwriter reasonably requests in writing, keep
each such registration or qualification (or exemption therefrom) effective
during the period such Registration Statement is required to be kept effective
and do any and all other acts or things necessary legally to enable the
disposition in such jurisdictions of the Transfer Restricted Securities covered
by the applicable Registration Statement; provided, however, that the Company
shall not be required to qualify generally to do business in any jurisdiction
where it is not then so qualified, take any action that would subject it to
general service of process in any such jurisdiction where it is not then so
subject or subject the Company to any tax in any such jurisdiction where it is
not then so subject;

            (i)   In connection with any sale or transfer of Transfer Restricted
Securities that will result in such securities no longer being Transfer
Restricted Securities, cooperate with the Holders and the managing underwriters,
if any, to (A) facilitate the timely preparation and delivery of certificates
representing Transfer Restricted Securities to be sold, which certificates shall
not bear any restrictive legends, for the Notes shall bear a CUSIP number
different from the CUSIP number


                                      -11-
<PAGE>   12
for the Transfer Restricted Securities and for any Transfer Restricted
Securities shall be in a form eligible for deposit with The Depository Trust
Company and (B) enable such Transfer Restricted Securities to be in such
denominations and registered in such names as the managing underwriters, if any,
or Holders may reasonably request at least two Business Days prior to any sale
of Transfer Restricted Securities;

            (j)   Use its reasonable best efforts to cause the offering of the
Transfer Restricted Securities covered by the Registration Statement to be
registered with or approved by such other governmental agencies or authorities
within the United States, except as may be reasonably required as a consequence
of the nature of a Holder's business, in which case the Company will cooperate
in all reasonable respects with the filing of such Registration Statement and
the granting of such approvals as may be reasonably necessary to enable the
seller or sellers thereof or the underwriters, if any, to consummate the
disposition of such Transfer Restricted Securities; provided, however, that the
Company shall not be required to register the Transfer Restricted Securities in
any jurisdiction that would require the Company to qualify to do business in any
jurisdiction where it is not then so qualified, subject it to general service of
process in any such jurisdiction where it is not then so subject or subject the
Company to any tax in any such jurisdiction where it is not then so subject or
to;

            (k)   Upon the occurrence of any event contemplated by Section
4(c)(vi) hereof, as promptly as reasonably practicable, prepare a supplement or
amendment, including, if appropriate, a post-effective amendment, to each
Registration Statement or a supplement to the related Prospectus or any document
incorporated or deemed to be incorporated therein by reference, and file any
other required document so that, as thereafter delivered, such Prospectus will
not contain an 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,
in light of the circumstances under which they were made, not misleading;

            (l)   Prior to the effective date of the first Registration
Statement relating to the Transfer Restricted Securities, to provide a CUSIP
number for the Transfer Restricted Securities to be sold pursuant to the
Registration Statement;

            (m)   Enter into such agreements (including an underwriting
agreement in form, scope and substance as are customary in underwritten
offerings) reasonably satisfactory to the Company and take all such other
reasonable actions in connection therewith (including those reasonably requested
by the managing underwriters, if any, or the Holders of a majority in aggregate
principal amount of the Transfer Restricted Securities being sold) in order to
expedite or facilitate the sale of such Transfer Restricted Securities;
provided, however, that the Company is required to facilitate no more than two
underwritten offerings. In such connection, whether or not an underwriting
agreement is entered into and whether or not the registration is an underwritten
registration, (i) make such representations and warranties to the Holders of
such Transfer Restricted Securities and the underwriters, if any, with respect
to the business of the Company and its subsidiaries (including with respect to
businesses or assets acquired or to be acquired by any of


                                      -12-
<PAGE>   13
them), and the Registration Statement, Prospectus and documents, if any,
incorporated or deemed to be incorporated by reference therein, in each case, in
form, substance and scope as are customarily made by issuers to underwriters in
underwritten offerings and reasonably acceptable to the Company, and confirm the
same if and when requested; (ii) seek to obtain opinions of counsel to the
Company and updates thereof (which counsel and opinions (in form, scope and
substance) shall be reasonably satisfactory to the managing underwriters, if
any, and Special Counsel to the Holders of the Transfer Restricted Securities
being sold) addressed to each selling Holder of Transfer Restricted Securities
and each of the underwriters, if any, covering the matters customarily covered
in opinions requested in underwritten offerings (including any such matters as
may be reasonably requested by such Special Counsel and underwriters); (iii) use
all reasonable efforts to obtain customary "cold comfort" letters and updates
thereof from the independent certified public accountants of the Company (and,
if necessary, any other independent certified public accountants of any
subsidiary of the Company or of any business acquired by the Company for which
financial statements and financial data is, or is required to be, included in
the Registration Statement), addressed (where reasonably possible) to each
selling Holder of Transfer Restricted Securities and each of the underwriters,
if any, such letters to be in customary form and covering matters of the type
customarily covered in "cold comfort" letters in connection with underwritten
offerings; (iv) if an underwriting agreement is entered into, the same shall
contain indemnification provisions and procedures no less favorable to the
selling Holders of Transfer Restricted Securities and the underwriters, if any,
than those set forth in Section 6 hereof (or such other provisions and
procedures acceptable to Holders of a majority in aggregate principal amount of
the Transfer Restricted Securities covered by such Registration Statement and
the managing underwriters); and (v) deliver such documents and certificates as
may be reasonably requested by the Holders of majority in aggregate principal
amount of the Transfer Restricted Securities being sold, their Special Counsel
or the managing underwriters, if any, to evidence the continued validity of the
representations and warranties made pursuant to clause (i) of this Section 4(m)
and to evidence compliance with any customary conditions contained in the
underwriting agreement or other agreement entered into by the Company;

            (n)   Make available for inspection by a representative of the
Holders of Transfer Restricted Securities being sold, any underwriter
participating in any such disposition of Transfer Restricted Securities, if any,
and any attorney, consultant or accountant retained by such selling Holders or
underwriter, at the offices where normally kept, during reasonable business
hours, all financial and other records, pertinent corporate documents and
properties of the Company and its subsidiaries as they may reasonably request,
and cause the officers, directors, agents and employees of the Company and its
subsidiaries to supply all information in each case reasonably requested by any
such representative, underwriter, attorney, consultant or accountant in
connection with such Registration Statement, provided, however, that such
persons shall first agree in writing with the Company that any information that
is reasonably and in good faith designated by the Company in writing as
confidential at the time of delivery or inspection (as the case may be) of such
information shall be kept confidential by such persons, unless (i) disclosure of
such information is required by court or administrative order or is necessary to
respond to inquiries of regulatory authorities, (ii) disclosure of such
information is required by law (including any disclosure requirements pursuant
to Federal securities laws in connection with the filing of any Registration
Statement or the


                                      -13-
<PAGE>   14
use of any Prospectus), (iii) such information becomes generally available to
the public other than as a result of a disclosure or failure to safeguard by any
such person or (iv) such information becomes available to any such person from a
source other than the Company and such source is not bound by a confidentiality
agreement.

            (o)   Use its reasonable best efforts to cause the Indenture to be
qualified under the TIA not later than the effective date of the first
Registration Statement relating to the Transfer Restricted Securities; and in
connection therewith, cooperate with the Trustee and the Holders of Notes
constituting Transfer Restricted Securities to effect such changes to the
Indenture, if any, as may be required for such Indenture to be so qualified in
accordance with the terms of the TIA; and execute, and use its best efforts to
cause the Trustee to execute, all customary documents as may be required to
effect such changes, and all other forms and documents (including Form T-1)
required to be filed with the SEC to enable the Indenture to be so qualified
under the TIA in a timely manner.

            (p)   Comply with applicable rules and regulations of the SEC and
make generally available to its security holders earning statements satisfying
the provisions of Section 11(a) of the Securities Act or Rule 158 of the
Securities Act (or any similar rule promulgated under the Securities Act), no
later than 45 days after the end of any 12-month period (or 90 days after the
end of any 12-month period if such period is a fiscal year) (i) commencing at
the end of any fiscal quarter in which Transfer Restricted Securities are sold
to underwriters in a firm commitment or best efforts underwritten offering and
(ii) if not sold to underwriters in such an offering, commencing on the first
day of the first fiscal quarter after the effective date of a Registration
Statement, which statement shall cover said period, consistent with the
requirements of Rule 158 of the Securities Act; and

            (q)   (i) list all shares of Common Stock covered by such
Registration Statement on any securities exchange on which the Common Stock is
then listed or (ii) if required by the applicable rules, authorize for quotation
on the National Association of Securities Dealers Automated Quotation System
("Nasdaq") or the National Market of Nasdaq all Common Stock covered by such
Registration Statement if the Common Stock is then so authorized for quotation.

      5.    Registration Expenses

            (a)   All fees and expenses incident to the performance of or
compliance with this Agreement by the Company shall be borne by it whether or
not any Registration Statement is filed or becomes effective and whether or not
any securities are offered or sold pursuant to any Registration Statement. The
fees and expenses referred to in the foregoing sentence shall include, without
limitation, (i) all registration and filings fees (including, without
limitation, fees and expenses (A) with respect to filings required to be made
with the National Association of Securities Dealers, Inc. and (B) in compliance
with securities or Blue Sky laws (including, without limitation and in addition
to that provided for in (b) below, fees and disbursements of counsel for the
underwriters or the Special Counsel in connection with Blue Sky qualifications
of the Transfer Restricted Securities and determination of the eligibility of
the Transfer Restricted Securities for investment under the laws of such
jurisdictions as the managing underwriters, if any, or Holders of a majority in
aggregate principal amount of Transfer Restricted Securities, may designate)),
(ii) printing expenses (including,


                                      -14-
<PAGE>   15
without limitation, expenses of printing certificates for Transfer Restricted
Securities in a form eligible for deposit with The Depository Trust Company and
of printing Prospectuses if the printing of Prospectuses is required by the
managing underwriters, if any, or by the Holders of a majority in aggregate
principal amount of the Transfer Restricted Securities included), (iii)
messenger, telephone and delivery expenses of the Company, (iv) fees and
disbursements of counsel for the Company and the Special Counsel (plus any local
counsel deemed appropriate by the Holders of a majority in aggregate principal
amount of the Transfer Restricted Securities) in accordance with the provisions
of Section 5(b) hereof, (v) fees and disbursements of all independent certified
public accountants referred to in Section 4(m)(iii) (including, without
limitation, the expenses of any special audit and "comfort" letters required by
or incident to such performance), (vi) Securities Act liability insurance, if
the Company so desires such insurance, and (vii) fees and expenses of all other
persons retained by the Company. In addition, the Company shall pay its internal
expenses (including, without limitation, all salaries and expenses of its
officers and employees performing legal or accounting duties), the expense of an
annual audit and the fees and expenses incurred in connection with the listing
of the securities to be registered on any securities exchange or the Nasdaq
National Market. Notwithstanding anything in this Agreement to the contrary,
each Holder shall pay all underwriting discounts and brokerage commissions with
respect to any Transfer Restricted Securities sold by it.

            (b)   In connection with any registration hereunder, the Company
shall reimburse the Holders of the Transfer Restricted Securities being
registered or tendered for in such registration for the reasonable fees and
disbursements of not more than one firm of attorneys representing the selling
Holders (in addition to any local counsel) as Special Counsel, which firm shall
initially be chosen by the Holders of a majority in aggregate principal amount
of the Transfer Restricted Securities. Testa, Hurwitz & Thibeault, LLP shall be
Special Counsel for all purposes hereof, but which may, with the written consent
of the Purchasers (which shall not be unreasonably withheld), be another
nationally recognized law firm experienced in securities law matters designated
by the Company unless and until another Special Counsel shall have been selected
by a majority in aggregate principal amount of the Transfer Restricted
Securities and notice hereof shall have been given to the Company.

      6.    Indemnification

            (a)   The Company agrees to indemnify and hold harmless (i) the
Purchasers, (ii) each Holder, (iii) each person, if any, who controls (within
the meaning of Section 15 of the Securities Act or Section 20 of the Exchange
Act) any of the foregoing (any of the persons referred to in this clause (iii)
being hereinafter referred to as a "Controlling Person"), and (iv) the
respective officers, directors, partners, employees, representatives and agents
of the Purchasers, the Holders (including predecessor Holders), or any
Controlling Person (any person referred to in clause (i), (ii), (iii) or (iv)
may hereinafter be referred to as an "Indemnified Person"), from and against any
and all losses, claims, damages, liabilities, expenses and judgments caused by
any untrue statement or alleged untrue statement of a material fact contained in
any Registration Statement or Prospectus or in any amendment or supplement
thereto or in any preliminary Prospectus, or caused by any omission or alleged
omission to state therein a material fact required to be stated therein or
necessary


                                      -15-
<PAGE>   16
to make the statements therein (in the case of any Prospectus or supplement
thereto, in light of the circumstances under which they were made) not
misleading, except insofar as such losses, claims, damages, liabilities,
expenses or judgments are caused by any such untrue statement or omission or
alleged untrue statement or omission based upon information relating to any
Indemnified Person furnished to the Company by or on behalf of such Indemnified
Person expressly for use therein; (which shall include without limitation, the
Requisite Information in the Notice and Questionnaire provided to the Company by
such Indemnified Person) provided, however, that the foregoing indemnity with
respect to any preliminary Prospectus shall not inure to the benefit of any
Indemnified Person from whom the person asserting such losses, claims, damages,
liabilities, expenses and judgments purchased securities if such untrue
statement or omission or alleged untrue statement or omission made in such
preliminary Prospectus is eliminated or remedied in the Prospectus and a copy of
the Prospectus shall not have been furnished to such person in a timely manner
due to the wrongful action or wrongful inaction of such Indemnified Person,
whether as a result of negligence or otherwise.

            (b)   In case any action shall be brought against any Indemnified
Person, based upon any Registration Statement or any such Prospectus or any
amendment or supplement thereto and with respect to which indemnity may be
sought against the Company, such Indemnified Person shall promptly notify the
Company in writing and the Company shall assume the defense thereof, including
the employment of counsel reasonably satisfactory to such Indemnified Person and
payment of all fees and expenses. Any Indemnified Person shall have the right to
employ separate counsel in any such action and participate in the defense
thereof, but the fees and expenses of such counsel shall be at the expense of
such Indemnified Person, unless (i) the employment of such counsel shall have
been specifically authorized in writing by the Company, (ii) the Company shall
have failed to assume the defense and employ counsel or (iii) such Indemnified
Person or Persons shall have been advised by counsel that there may be a
conflict between the positions of the indemnifying party or parties and of the
indemnified party or parties in conducting the defense of such action or
proceeding or that there may be legal defenses available to such Indemnified
Person or Persons different from or in addition to those available to the
indemnifying party or parties (in which case the Company shall not have the
right to assume the defense of such action on behalf of such Indemnified
Person), it being understood, however, that the Company shall not, in connection
with any one such action or separate but substantially similar or related
actions in the same jurisdiction arising out of the same general allegations or
circumstances, be liable for the fees and expenses of more than one separate
firm of attorneys (in addition to any local counsel) for all such Indemnified
Persons, which firm shall be designated in writing by such Indemnified Persons,
and that all such fees and expenses shall be reimbursed as they are incurred.
The Company shall not be liable for any settlement of any such action effected
without its written consent but if settled with the written consent of the
Company, the Company agrees to indemnify and hold harmless, in accordance with
this Section 6, any Indemnified Person from and against any loss or liability by
reason of such settlement. No Indemnifying Party shall, without the prior
written consent of the Indemnified Party, effect any settlement of any pending
or threatened proceeding in respect of which any Indemnified Party is or could
have been a party and indemnity could have been sought hereunder by such


                                      -16-
<PAGE>   17
Indemnified Party, unless such settlement includes an unconditional release of
such Indemnified Party from all liability on claims that are the subject matter
of such proceeding.

            (c)   In connection with any Registration Statement pursuant to
which any Holder (or predecessor Holder) sold or offered for resale Transfer
Restricted Securities, such Holder (or predecessor Holder) agrees, severally and
not jointly, to indemnify and hold harmless the Company, its directors, its
officers, employees, representatives, agents and any person controlling the
Company within the meaning of Section 15 of the Securities Act or Section 20 of
the Exchange Act (any such person referred to as a "Company Indemnified Person"
and collectively with the Indemnified Persons, any such person referred to as an
"Indemnified Party"), to the same extent as the foregoing indemnity from the
Company to each Indemnified Person but only with reference to information
relating to such Indemnified Person furnished by or on behalf of such
Indemnified Person expressly for use in such Registration Statement (which shall
include, without limitation, the Requisite Information in the Notice and
Questionnaire provided to the Company by such Indemnified Person). In case any
action shall be brought against any Company Indemnified Person, based on such
Registration Statement and in respect of which indemnity may be sought against
any Indemnifying Party, the Indemnifying Party shall have the rights and duties
given to the Company (except that if the Company shall have assumed the defense
thereof, such Indemnifying Party shall not be required to do so, but may employ
separate counsel therein and participate in defense thereof but the fees and
expenses of such counsel shall be at the expense of such Indemnifying Party),
and the Company Indemnified Person shall have the rights and duties given to the
Indemnified Person by Section 6(b) hereof.

            (d)   If the indemnification provided for in this Section 6 is
unavailable to an Indemnified Party in respect of any losses, claims, damages,
liabilities, expenses or judgments referred to therein, then each Indemnifying
Party, in lieu of indemnifying such Indemnified Party, shall contribute to the
amount paid or payable by such Indemnified Party as a result of such losses,
claims, damages, liabilities, expenses and judgments (i) in such proportion as
is appropriate to reflect the relative benefits received by the Company on the
one hand and each Indemnified Person on the other hand pursuant to the Purchase
Agreement or from the offering for resale of the Transfer Restricted Securities
or (ii) if the allocation provided by clause (i) above is not permitted by
applicable law, in such proportion as is appropriate to reflect not only the
relative benefits referred to in clause (i) above but also the relative fault of
the Company and each such Indemnified Person in connection with the statements
or omissions which resulted in such losses, claims, damages, liabilities,
expenses or judgments, as well as any other relevant equitable considerations.
The relative fault of the Company and each such Indemnified Person shall be
determined by reference to, among other things, whether the untrue or alleged
untrue statement of a material fact or the omission to state a material fact
relates to information supplied by the Company or such Indemnified Person and
the parties' relative intent, knowledge, access to information and opportunity
to correct or prevent such statement or omission.

            The Company, the Holders and the Purchasers agree that it would not
be just and equitable if contribution pursuant to this Section 6(d) were
determined by pro rata allocation (even if


                                      -17-
<PAGE>   18
the Indemnified Person were treated as one entity for such purpose) or by any
other method of allocation which does not take account of the equitable
considerations referred to in the immediately preceding paragraph. The amount
paid or payable by an Indemnified Party as a result of the losses, claims,
damages, liabilities, expenses or judgments referred to in the immediately
preceding paragraph shall be deemed to include, subject to the limitations set
forth above, any legal or other expenses reasonably incurred by such Indemnified
Party in connection with investigating or defending any such action or claim.
Notwithstanding the provisions of this Section 6, no Indemnified Person shall be
required to contribute any amount in excess of the amount by which the total net
profit received by it in connection with the sale of the Transfer Restricted
Securities pursuant to this Agreement exceeds the amount of any damages which
such Indemnified Person has otherwise been required to pay by reason of such
untrue or alleged untrue statement or omission or alleged omission. No person
guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of
the Securities Act) shall be entitled to contribution from any person who was
not guilty of such fraudulent misrepresentation. The Indemnified Persons'
obligations to contribute pursuant to this Section 6(d) are several in
proportion to the respective amount of Transfer Restricted Securities included
in and sold pursuant to any such Registration Statement by each Indemnified
Person and not joint.

      7.    Rules 144 and 144A

            The Company shall file the reports required to be filed by it under
the Securities Act and the Exchange Act in a timely manner and, if at any time
it is not required to file such reports but in the past had been required to or
did file such reports, it will, upon the request of any Holder, make available
other information as required by, and so long as necessary, to permit sales of
its Transfer Restricted Securities pursuant to Rule 144 and Rule 144A.
Notwithstanding the foregoing, nothing in this Section 7 shall be deemed to
require the Company to register any of its securities pursuant to the Exchange
Act.

      8.    Underwritten Registrations

            If any of the Transfer Restricted Securities covered by the Shelf
Registration Statement are to be sold in an underwritten offering, the
investment banker or investment bankers and manager or managers that will
administer the offering will be investment bankers of recognized national
standing selected by the Holders of a majority in aggregate principal amount of
such the Notes (or the proportional amount of Common Stock held as Transfer
Restricted Securities) included in such offering, subject to the consent of the
Company (which will not be unreasonably withheld or delayed).

            No person may participate in any underwritten registration hereunder
unless such person (i) agrees to sell such person's Transfer Restricted
Securities on the basis reasonably provided in any underwriting arrangements
approved by the persons entitled hereunder to approve such arrangements and (ii)
completes and executes all questionnaires, powers of attorney, indemnities
underwriting agreements, lock-up agreements and other documents reasonably
required under the terms of such underwriting arrangements.


                                      -18-
<PAGE>   19
      9.    Miscellaneous

            (a)   Remedies. In the event of a breach by the Company or by a
Holder of any of their respective obligations under this Agreement, each Holder
or the Company, in addition to being entitled to exercise all rights granted by
law, including, without limitation, recovery of damages, will be entitled to
specific performance of its rights under this Agreement. The Company and each
Holder agree that monetary damages would not be adequate compensation for any
loss incurred by reason of a breach by it of any of the provisions of this
Agreement and hereby further agree that, in the event of any action for specific
performance in respect of such breach, they shall waive the defense that a
remedy at law would be adequate. This Section 9(a) shall not apply to Section 3.

            (b)   No Inconsistent Agreements. The Company shall not enter into
any agreement with respect to its securities that is inconsistent with the
rights granted to the Holders in this Agreement or otherwise conflicts with the
provisions hereof. The Company is not currently a party to any agreement
granting any registration rights with respect to any of its securities to any
person which conflicts with the Company's obligations hereunder or gives any
other party the right to include any securities in any Registration Statement
filed pursuant hereto, except for such rights and conflicts as have been
irrevocably waived. Without limiting the generality of the foregoing until the
date at which the Securities (as defined in the Purchase Agreement) cease to be
Transfer Restricted Securities, without the written consent of the Holders of a
majority in aggregate principal amount of the Transfer Restricted Securities,
the Company shall not grant to any person the right to request it to register
any of its securities under the Securities Act unless the rights so granted are
subject in all respect to the prior rights of the Holders set forth herein, and
are not otherwise in conflict or inconsistent with the provisions of this
Agreement.

            (c)   No Adverse Action Affecting the Transfer Restricted
Securities. The Company will not take any action with respect to the Transfer
Restricted Securities which would adversely affect the ability of any of the
Holders to include such Transfer Restricted Securities in a registration
undertaken pursuant to this Agreement.

            (d)   No Piggyback on Registrations. After the date hereof, the
Company shall not grant to any of its security holders (other than the Holders
in such capacity) the right to include any of its securities in the Shelf
Registration Statement.

            (e)   Amendments and Waivers. The provisions of this Agreement,
including the provisions of this sentence, may not be amended, modified or
supplemented, and waivers or consents to departures from the provisions hereof,
may not be given, without the written consent of the Holders of a majority in
aggregate principal amount of the Transfer Restricted Securities; provided,
however, that, for the purposes of this Agreement, Transfer Restricted
Securities that are owned, directly or indirectly, by either the Company or an
Affiliate of the Company are not deemed outstanding. Notwithstanding the
foregoing, a waiver or consent to depart from the provisions hereof with respect
to a matter that relates exclusively to the rights of Holders whose Transfer
Restricted Securities are being sold pursuant to an underwritten offering and
that does not directly or indirectly affect the rights of other Holders may be
given by Holders of a majority in aggregate


                                      -19-
<PAGE>   20
principal amount of the Transfer Restricted Securities being sold by such
Holders pursuant to such an underwritten offering; provided, however, that the
provisions of this sentence may not be amended, modified, or supplemented except
in accordance with the provisions of the immediately preceding sentence.

            (f)   Notices. All notices and other communications provided for
herein shall be made in writing by hand-delivery, next day air courier,
certified first-class mail, return receipt requested or telecopy; provided a
copy of any such telecopy is immediately followed up by next day courier:

                  (i)   if to a Holder, to the address of such Holder as it
                        appears in the Note or Common Stock register of the
                        Company, as applicable;

                  (ii)  if to the Company, to:
                        Cephalon, Inc.
                        145 Brandywine Parkway
                        West Chester, PA 19380
                        Attn:  General Counsel
                        Telecopy No.: (610) 344-7563

                        with a copy to:
                        Morgan, Lewis & Bockius LLP
                        1701 Market Street
                        Philadelphia, PA  19103
                        Attn:  Richard A. Silfen, Esq.
                        Telecopy No.: (215) 963-5299

                  (iii) if to the Special Counsel, to:

                        Testa, Hurwitz & Thibeault, LLP
                        125 High Street
                        Boston, MA 02110
                        Attn: Mitchell S. Bloom, Esq.
                        Telecopy No.: (617) 248-7100

or such other Special Counsel at such other address and telecopy number as a
majority in aggregate principal amount of the Transfer Restricted Securities
shall have given notice to the Company as contemplated by Section 5(b) hereof.

            Except as otherwise provided in this Agreement, all such
communications shall be deemed to have been duly given, when delivered by hand,
if personally delivered; one Business Day after being timely delivered to a
next-day air courier, five Business Days after being deposited in the mail,
postage prepaid, if mailed; and when receipt is acknowledged by the recipient's
telecopier


                                      -20-
<PAGE>   21
machine, if telecopied; provided a copy of any such telecopy is immediately
followed up by next day courier.

            (g)   Successors and Assigns. This Agreement shall inure to the
benefit of and be binding upon the successors and permitted assigns of each of
the parties and shall inure to the benefit of each existing and future Holder.
The Company may not assign its rights or obligations hereunder without the prior
written consent of the Holders of a majority in aggregate principal amount of
the Transfer Restricted Securities, other than by operation of law pursuant to a
merger or consolidation to which the Company is a party. In the event the Notes
constituting Transfer Restricted Securities become convertible into common stock
of another person pursuant to Section 15.6 of the Indenture, the Company shall
cause such person to assume the Company's obligations hereunder.

            (h)   Counterparts. This Agreement may be executed in any number of
counterparts by the parties hereto, each of which when so executed shall be
deemed to be an original and all of which taken together shall constitute one
and the same instrument.

            (i)   GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY, AND
CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK, AS APPLIED TO
CONTRACTS MADE AND PERFORMED WITHIN THE STATE OF NEW YORK, WITHOUT REGARD TO
PRINCIPLES OF CONFLICTS OF LAW.

            (j)   Severability. The remedies provided herein are cumulative and
not exclusive of any remedies provided by law. If any term, provision, covenant
or restriction of this Agreement is held by a court of competent jurisdiction to
be invalid, illegal, void or unenforceable, the remainder of the terms,
provisions, covenants and restrictions set forth herein shall remain in full
force and effect and shall in no way be affected, impaired or invalidated, and
the parties hereto shall use their best efforts to find and employ an
alternative means to achieve the same or substantially the same result as that
contemplated by such term, provision, covenant or restriction. It is hereby
stipulated and declared to be the intention of the parties that they would have
executed the remaining terms, provisions, covenants and restrictions without
including any of such that may be hereafter declared invalid, illegal, void or
unenforceable.

            (k)   Headings. The headings in this Agreement are for convenience
of reference only and shall not limit or otherwise affect the meaning hereof.
All references made in this Agreement to "Section" and "paragraph" refer to such
Section or paragraph of this Agreement, unless expressly stated otherwise.

            (l)   Attorneys' Fees. In any action or proceeding brought to
enforce any provision of this Agreement, or where any provision hereof is
validly asserted as a defense, the prevailing party, as determined by the court,
shall be entitled to recover its reasonable attorneys' fees in addition to any
other available remedy.


                                      -21-
<PAGE>   22
      IN WITNESS WHEREOF, the parties have caused this Registration Rights
Agreement to be duly executed as of the date first written above.


                                          CEPHALON, INC.

                                          By:    /s/   J. Kevin Buchi
                                               ---------------------------------

                                          Name:    J. Kevin Buchi
                                                 -------------------------------
                                          -

                                          Title:    Senior VP and CFO
                                                  ------------------------------


The foregoing Registration Rights
Agreement is hereby confirmed and
agreed to as of the date first
written above:

ROBERTSON STEPHENS, INC.
ADAMS, HARKNESS & HILL, INC.
BANC OF AMERICA SECURITIES LLC
CIBC WORLD MARKETS CORP.
SG COWEN SECURITIES CORPORATION
UBS WARBURG LLC
U.S. BANCORP PIPER JAFFRAY INC.


By:   ROBERTSON STEPHENS, INC.

      By:______________________________
         Authorized Signatory
<PAGE>   23
                 5-1/4% CONVERTIBLE SUBORDINATED NOTES DUE 2006

                          REGISTRATION RIGHTS AGREEMENT

                             Dated as of May 7, 2001

                                     between

                                 CEPHALON, INC.
                                 as the Company,

                                       and
                            ROBERTSON STEPHENS, INC.
                          ADAMS, HARKNESS & HILL, INC.
                         BANC OF AMERICA SECURITIES LLC
                            CIBC WORLD MARKETS CORP.
                         SG COWEN SECURITIES CORPORATION
                                 UBS WARBURG LLC
                         U.S. BANCORP PIPER JAFFRAY INC.


                                  as Purchasers