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                                                                        Ex 10.16

            THIS REGISTRATION RIGHTS AGREEMENT is made as of June 20, 2000 by
and between DOV Pharmaceutical, Inc., a New Jersey corporation (the "COMPANY" ),
and the persons or entities set forth on Exhibit A and executing a signature
page hereto (collectively, "Holders").

                                    RECITALS:

            A. Pursuant to a preferred stock purchase agreement dated as of June
__, 2000 by and between the Company and Holders ("Purchase Agreement"), Holders
have subscribed for and the Company has issued to Holders up to 1,750,000 shares
of the Company's series C convertible preferred stock, par value $1.00 (the
"Shares"), convertible into shares of common stock, par value $.0001 per share
(the " Common Stock"), of the Company.

            B. The group of Holders set forth on SCHEDULE 1 ("First Closing
Holders") have entered into a registration rights agreement with the Company
dated May 31, 2000 ("First Closing Agreement") and now the Company desires to
admit the additional Holders set forth on SCHEDULE 2 and amend and restate the
registration rights agreement for all Holders.

            C. The parties acknowledge that the Company is party to a
registration rights agreement with Elan International Services, Ltd. ("Elan").
dated January 21, 2000 ("Elan Agreement"). It is the intent of the parties that
the rights granted hereunder not be in conflict with the Elan Agreement but
rather that the Holders have the rights as permitted by the Elan Agreement or
otherwise agreed to by Elan, including, without limitation (i) "piggyback"
registration rights PARI PASSU to the rights of the holders of registration
rights pursuant to the Elan Agreement ("Elan Holders"); and (ii) demand
registration rights entitling Elan Holders to participate with Holders or
Holders to participate with Elan Holders in such demand registration on a PRO
RATA basis.

            D. The parties desire to set forth herein their agreement related to
the granting of certain registration rights to Holders relating to their Common
Stock or securities convertible, exercisable or exchangeable for or into Common
Stock.

                                   AGREEMENT:

            The parties hereto agree as follows:

            1. CERTAIN DEFINITIONS. As used in this Agreement, the following
terms shall have the following respective meanings:

            "COMMISSION" shall mean the Securities and Exchange Commission or
any other federal agency at the time administering the Securities Act.

            "EXCHANGE ACT" shall mean the Securities Exchange Act of 1934, as
amended, or any similar federal statute and the rules and regulations of the
Commission thereunder, all as the same shall be in effect at the time.

            "HOLDERS" shall mean the Persons set forth on Exhibit A and
executing a signature

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page hereto and any Person who shall have acquired Registrable Securities from a
Holder as permitted herein, either individually or jointly as the case may be.

            "PERSON" shall mean an individual, a partnership, a company, an
association, a joint stock company, a trust, a joint venture, an unincorporated
organization and a governmental quasi-governmental entity or any department,
agency or political subdivision thereof.

            "REGISTRABLE SECURITIES" means (i) any shares of Common Stock held
by a Holder, (ii) any Common Stock issued to a Holder upon conversion of the
Shares, and (iii) any Common Stock issued in respect of the securities referred
to in clauses (i) and (ii) above upon any exercise of a preemptive right, stock
split, stock dividend, recapitalization or similar event, excluding in all
cases, however, any Registrable Securities sold by a Person in a transaction
(including a transaction pursuant to a registration statement under this
Agreement and transaction pursuant to Rule 144 promulgated under the Securities
Act) in which registration rights are not transferred as permitted pursuant to
this Agreement. Common Stock owned by a Holder shall cease to be Registrable
Securities (i) upon any sale by such Holder pursuant to a Registration
Statement, Section 4(2) of the Securities Act or Rule 144 under the Securities
Act or (ii) upon any assignment or transfer of the Registrable Securities in a
manner not in compliance with the Securities Act or this Agreement.

            The terms "REGISTER," "REGISTERED" and "REGISTRATION" refer to a
registration effected by preparing and filing a registration statement in
compliance with the Securities Act, and the declaration or ordering of the
effectiveness of such registration statement.

            "REGISTRATION EXPENSES" shall mean all expenses, other than Selling
Expenses, incurred by the Company in complying with Sections 2 or 3 hereof,
including all registration, qualification and filing fees, exchange listing
fees, printing expenses, escrow fees, fees and disbursements of counsel for the
Company, blue sky fees and expenses, the expense of any special audits incident
to or required by any such registration and the reasonable fees and
disbursements, not to exceed $10,000 in the aggregate, of one counsel for
Holders.

            "SECURITIES ACT" shall mean the Securities Act of 1933, as amended,
or any similar federal statute and the rules and regulations of the Commission
thereunder, all as the same shall be in effect at the time.

            "SELLING EXPENSES" shall mean all underwriting discounts, selling
commissions and stock transfer taxes applicable to the securities registered by
Holders and the costs of any accountants, counsel (in excess of $10,000) or
other experts reasonably retained by Holders.

            2. DEMAND REGISTRATIONS.

            (a) REQUESTS FOR REGISTRATION. Upon the approval of 65% of the
Holders in


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interest (on an as-converted basis), Holders acting jointly shall have one right
at any time from and after six months of the Company's initial public offering
of securities (an "IPO" ), to request registration under the Securities Act of
all or part of their Registrable Securities on Form S-1, S-2 or S-3 (if
available) or any similar or successor registration form ("Demand
Registration"), such form to be selected by the Company. A written request for a
Demand Registration shall specify the approximate number of Registrable
Securities requested to be registered. Within 10 days after receipt of any such
request, the Company shall give written notice of such requested registration to
the other Holders and the Elan Holders and, if they request to be included in
such registration, the Company shall include such Holders or Elan Holders'
Registrable Securities (as defined in the Elan Agreement) in such offering if
they have responded affirmatively within 10 days after the receipt of the
Company's notice. In turn, within 10 days after receipt of a written request for
a Demand Registration by the Elan Holders pursuant to the Elan Agreement, the
Company shall give written notice of such requested registration to the Holders
and, if they request to be included in such registration, the Company shall
include such Holders' Registrable Securities in such offering if they have
responded affirmatively within 10 days after receipt of the notice. Holders
acting jointly shall be entitled in the aggregate to request one Demand
Registration whether it is initiated by the Holders or Elan Holders, provided
that if the Holders are subject to cut-backs in connection with their
participation in a Demand Registration by the Elan Holders or the Holders (if
Elan participates in the Demand) the Holders shall be permitted one additional
Demand Registration, provided that in no event shall the Holders have more than
two Demand Registration rights. A registration shall not count as the permitted
Demand Registration until it has become effective unless such Demand
Registration has not become effective due solely to the fault of a Holder,
including a request by a majority in interest of Holders that such registration
be withdrawn, provided that if Holders pay or promptly reimburse the Company for
all the expenses incurred in connection with the withdrawn Demand Registration
it shall not be counted. The Company shall pay all Registration Expenses in
connection with a Demand Registration whether or not a Demand Registration has
become effective, provided that the Company shall not be obligated to pay such
Registration Expenses if the Demand Registration has not become effective due to
the fault (including such request to withdraw) of a Holder.

            (b) PRIORITY ON DEMAND REGISTRATIONS. If a Demand Registration is an
underwritten offering and the managing underwriters advise the Company in
writing that in their opinion the number of Registrable Securities and, if
permitted hereunder, other securities requested to be included in such offering,
exceeds the number of Registrable Securities and other securities, if any, that
can be sold in such offering without adversely affecting the marketability of
the offering, the Company shall include in such registration:

            (i) first but subject to underwriter cut-back to eliminate such
excess, the Registrable Securities requested to be included in such registration
by Holders together with any securities held by third parties holding a similar,
right, granted prior to the date hereof or otherwise approved by a majority in
interest of the Holders, to be included in such registration


                                       3
<Page>

(or, if necessary, such Registrable Securities or other securities PRO RATA
among the holders thereof); and

            (ii) thereafter, other securities requested to be included in such
registration or sold by the Company.

            (c) RESTRICTIONS ON DEMAND REGISTRATIONS. The Company may postpone
for up to six months in any 12 month period the filing or the effectiveness of a
registration statement for a Demand Registration if the Company determines in
good faith that such Demand Registration would have a material adverse effect on
any proposal or plan by the Company to engage in any financing, acquisition or
disposition of assets (other than in the ordinary course of business) or any
merger, consolidation, tender offer or similar transaction or would require
disclosure of any information that the board of directors of the Company
determines in good faith would be detrimental to the Company, provided that in
such event, Holders initially shall be entitled to withdraw such request and, if
such request is withdrawn, such Demand Registration shall not count as the one
permitted Demand Registration hereunder and the Company shall pay any
Registration Expenses in connection with such registration.

            (d) SELECTION OF UNDERWRITERS. The Company shall have the right to
select the investment banker(s) and manager(s) to administer an offering
pursuant to a Demand Registration subject to a reasonable objection by a
majority in interest of Holders, in which case the Holders, by majority in
interest vote, shall have right to select such person(s) subject to a reasonable
objection by the Company.

            (e) OTHER REGISTRATION RIGHTS. The Company shall not grant to any
Persons the right to request the Company to register any equity securities of
the Company, or any securities convertible or exchangeable into or exercisable
for such securities, that is in conflict with the rights granted to Holders,
without the prior written consent of Holders; it being understood that the
Company may grant rights to other Persons to (i) participate in Piggyback
Registrations so long as such rights are subordinate or PARI PASSU to the rights
of the holders of Registrable Securities with respect to such Piggyback
Registrations and (ii) demand registrations so long as Holders are entitled to
participate in one such demand registration with such Persons PRO RATA on the
basis of the number of shares owned by Holders.

            3. PIGGYBACK REGISTRATIONS. (a) RIGHT TO PIGGYBACK. At any time the
Company shall propose to register Common Stock under the Securities Act (other
than in a registration on Form S-3 relating to sales of securities to
participants in a Company dividend reinvestment plan, S-4 or S-8 or any
successor form or in connection with an acquisition or exchange offer) (each, a
"Piggyback Registration"), the Company shall give prompt written notice to all
Holders of Registrable Securities of its intention to effect such a registration
and, subject to Section 3(b) and the other terms of this Agreement, shall
include in such registration all Registrable Securities that are permitted under
applicable securities laws to be included in the form of registration statement


                                       4
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selected by the Company and with respect to which the Company has received
written requests for inclusion therein by a Holder within 15 days after the
receipt of the Company's notice.

            (b) PRIORITY ON PIGGYBACK REGISTRATIONS. Subject to Section 2(a), if
a Piggyback Registration is an underwritten registration, and the managing
underwriters advise the Company in writing that in their opinion the number of
securities requested to be included in such registration exceeds the number
which can be sold in such offering without adversely affecting the marketability
of the offering, the Company shall include in such registration:

            (i) first, the securities the Company proposes to sell;

            (ii) subject to underwriter cut-back to eliminate such excess, any
securities having the right to be included in such registration prior to the
securities of Holders pursuant to a right granted prior to the date hereof or
otherwise approved by a majority in interest of the Holders;

            (iii) subject to underwriter cut-back to eliminate such excess, the
Registrable Securities requested to be included in such registration by Holders
and any securities requested to be included in such registration by any other
Person, if necessary, PRO RATA among Holders and such other Persons; and

            (iv) thereafter (but so subject) other securities requested to be
included in such registration.

            If Holders are included in such a registration they shall execute an
underwriting agreement in form and substance satisfactory to the managing
underwriters.

            (c) RIGHT TO TERMINATE REGISTRATION. If, at any time after giving
written notice of its intention to register any of its securities as set forth
in Section 3(a) and prior to the effective date of the registration statement
filed in connection with such registration, the Company shall determine for any
reason not to register such securities, the Company may, at its election, give
written notice of such determination to Holders and thereupon be relieved of its
obligation to register any Registrable Securities in connection with such
registration (but not from its obligation to pay the Registration Expenses in
connection therewith as provided herein).

            (d) SELECTION OF UNDERWRITERS. Except as set forth in Section 2(d),
the Holders shall have no right to to select the investment banker(s) and
manager(s) to administer an offering pursuant to a Piggyback Registration by
virtue of this Agreement.

            4. EXPENSES OF REGISTRATION. Except as otherwise provided herein,
all Registration Expenses incurred in connection with all registrations pursuant
to Sections 2 and 3 shall be borne by the Company. All Selling Expenses relating
to securities registered on behalf of Holders shall be borne by Holders.


                                       5
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            5. HOLDBACK AGREEMENTS. (a) The Company agrees (i) not to effect any
public sale or distribution of its equity securities, or any securities
convertible into or exchangeable or exercisable for such securities, during the
seven days prior to and during the 180-day period beginning on the effective
date of any underwritten Demand Registration or any underwritten Piggyback
Registration (except as part of such underwritten registration or pursuant to
registrations on Form S-8 or any successor form), unless the underwriters
managing the registered public offering otherwise agree, and (ii) to use
reasonable efforts to cause each officer, director and holder of at least 5% (on
a fully-diluted basis) of its Common Stock, or any securities convertible into
or exchangeable or exercisable for Common Stock, purchased from the Company at
any time after the date of this Agreement (other than in a registered public
offering) to agree not to effect any public sale or distribution (including
sales pursuant to Rule 144 or any similar provision then in effect under the
Securities Act) of any such securities during such period (except as part of
such underwritten registration, if otherwise permitted), unless the underwriters
managing the registered public offering otherwise agree.

            (b) Holders agree if requested by the managing underwriter or
underwriters in an underwritten offering of securities of the Company, not to
effect any offer, sale, distribution or transfer of Registrable Securities,
including a sale pursuant to Rule 144 (or any similar provision then in effect)
under the Securities Act (except as part of such underwritten registration),
during the seven-day period prior to, and during the 180-day period (or such
shorter period as may be agreed to by the parties hereto) following, the
effective date of such Registration Statement to the extent timely notified in
writing by the Company or the managing underwriter or underwriters, provided
that the officers and directors of the Company are subject to the same
restriction.

            6. REGISTRATION PROCEDURES. Whenever Holders have requested that any
Registrable Securities be registered pursuant to this Agreement, the Company
shall use its best efforts to effect the registration and the sale of such
Registrable Securities in accordance with the intended method of distribution
thereof, and pursuant thereto the Company shall as expeditiously as possible:

            (a) subject to Section 2(c) hereof, prepare and file with the
Commission a registration statement on any form for which the Company qualifies
with respect to such Registrable Securities and use its best efforts to cause
such registration statement to become effective (provided that the Company shall
(i) furnish to the counsel selected by Holders copies of all such documents
proposed to be filed, which documents shall be subject to the review of such
counsel, and (ii) notify Holders of any stop order issued or threatened by the
Commission);

            (b) subject to Section 2(c) hereof, prepare and file with the
Commission such amendments and supplements to such registration statement and
the prospectus used in connection therewith as may be necessary to keep such
registration statement effective for a period equal to the shorter of (i) six
months and (ii) the time by which all Registrable Securities


                                       6
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covered by such registration statement have been sold, and comply with the
provisions of the Securities Act with respect to the disposition of all such
Registrable Securities covered by such registration statement during such period
in accordance with the intended methods of disposition by the sellers thereof
set forth in such registration statement;

            (c) furnish to each seller of Registrable Securities such number of
copies of such registration statement, each amendment and supplement thereto,
the prospectus included in such registration statement (including each
preliminary prospectus) and such other documents as such seller may reasonably
request in order to facilitate the disposition of the Registrable Securities
owned by such seller;

            (d) use its best efforts to register or qualify such Registrable
Securities under such other securities or blue sky laws of such jurisdiction as
any seller reasonably requests and do any and all other acts and things that may
be reasonably necessary or advisable to enable such seller to consummate the
disposition in such jurisdictions of the Registrable Securities owned by such
seller (provided that the Company shall not be required to (i) qualify generally
to do business in any jurisdiction where it would not otherwise be required to
qualify but for this Section 6(d), (ii) subject itself to taxation in any
jurisdiction or (iii) consent to general service of process in any such
jurisdiction);

            (e) notify each seller of such Registrable Securities, at any time
when a prospectus relating thereto is required to be delivered under the
Securities Act, of the happening of any event as a result of which the
prospectus included in such registration statement contains an untrue statement
of a material fact or omits any fact necessary to make the statements therein
not misleading, and, at the request of any such seller, the Company shall
prepare a supplement or amendment to such prospectus so that, as thereafter
delivered to the purchasers of such Registrable Securities, such prospectus
shall not contain an untrue statement of a material fact or omit to state any
fact necessary to make the statements therein not misleading; provided that the
Company shall not be required to amend the registration statement or supplement
the Prospectus for a period of up to six months if the board of directors
determines in good faith and so notifies Holders that to do so would have a
material adverse effect on any proposal or plan by the Company to engage in any
financing, acquisition or disposition of assets (other than in the ordinary
course of business) or any merger, consolidation, tender offer or similar
transaction or would require the disclosure of any information that the board of
directors determines in good faith the disclosure of which would be detrimental
to the Company, it being understood that the period for which the Company is
obligated to keep the Registration Statement effective shall be extended for a
number of days equal to the number of days the Company delays amendments or
supplements pursuant to this provision. Upon receipt of any notice pursuant to
this Section 6(e) Holders shall suspend all offers and sales of securities of
the Company and all use of any prospectus until advised by the Company that
offers and sales may resume, and shall keep confidential the fact and content of
any notice given by the Company pursuant to this section 6(e), unless such
disclosure is required by law or otherwise becomes public or upon the written


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advice of accountants to a Holder (which writing is provided to the Company
prior to any such disclosure) that such disclosure is required to deliver an
auditor's opinion in connection with the preparation of such Holder's financial
statements.

            (f) use its best efforts to cause all such Registrable Securities to
be listed on each securities exchange or quotation system on which similar
securities issued by the Company are then listed;

            (g) provide a transfer agent and registrar for all such Registrable
Securities not later than the effective date of such registration statement;

            (h) enter into such customary agreements (including underwriting
agreements in customary form) and take all such other actions as Holders
reasonably request in order to expedite or facilitate the disposition of such
Registrable Securities (including effecting a stock split or a combination of
shares);

            (i) make available for inspection by Holders, any underwriter
participating in any disposition pursuant to such registration statement and any
attorney, accountant or other agent retained by any such seller or underwriter
all pertinent financial and other records, pertinent corporate documents and
properties of the Company, and cause the Company's officers, directors,
employees and independent accountants to supply all information reasonably
requested by any such seller, underwriter, attorney, accountant or agent in
connection with such registration statement;

            (j) otherwise use its best efforts to comply with all applicable
rules and regulations of the Commission, and make available to its security
holders, as soon as reasonably practicable, an earnings statement covering the
period of at least 12 months beginning with the first day of the Company's first
full calendar quarter after the effective date of the registration statement,
which earnings statement shall satisfy the provisions of Section 11(a) of the
Securities Act and Rule 158 thereunder;

            (k) use its best efforts to secure all legal opinions reasonably
necessary to effect the registration statement, in form and substance as is
customarily given to underwriters in an underwritten public offering;

            (l) in the event of the issuance of any stop order suspending the
effectiveness of a registration statement, or of any order suspending or
preventing the use of any related prospectus or suspending the qualification of
any common stock included in such registration statement for sale in any
jurisdiction, use its best efforts promptly to obtain the withdrawal of such
order; and

            (m) use its best efforts to obtain a so-called "cold comfort" letter
from the Company's independent public accountants in customary form and covering
such matters of the


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type customarily covered by cold comfort letters.

            7. INDEMNIFICATION. (a) The Company shall indemnify, to the fullest
extent permitted by applicable law, Holders, their officers and directors and
each Person who controls such Holders (within the meaning of the Securities Act)
against all losses, claims, damages, liabilities, expenses or any amounts paid
in settlement of any litigation, investigation or proceeding commenced or
threatened (collectively, "Claims") to which such indemnified party may become
subject under the Securities Act insofar as such Claim arose out of (i) any
untrue or alleged untrue statement of material fact contained, on the effective
date thereof, in any registration statement, prospectus or preliminary
prospectus or any amendment thereof or supplement thereto or (ii) any omission
or alleged omission to state therein a material fact required to be stated
therein or necessary to make the statements therein not misleading, except
insofar as the same are caused by or contained in or omitted from any
information furnished in writing to the Company by Holders expressly for use
therein or by Holders' failure(s) to deliver a copy of the registration
statement or prospectus or any amendments or supplements thereto after the
Company has furnished Holders with a sufficient number of copies of the same. In
connection with an underwritten offering, the Company shall indemnify such
underwriters, their officers and directors and each Person who controls such
underwriters (within the meaning of the Securities Act) to the same extent as
provided above with respect to the indemnification of Holders.

            (b) In connection with any registration statements in which a Holder
is participating, each such Holder shall furnish to the Company in writing such
customary information and affidavits as the Company reasonably requests for use
in connection with any such registration statement or prospectus (the "Seller's
Information") and, to the fullest extent permitted by applicable law shall
indemnify the Company and each other Holder and the directors and officers and
each Person who controls the Company or such other Holder (within the meaning of
the Securities Act) against any and all Claims to which each such indemnified
party may become subject under the Securities Act insofar as such Claim arose
out of (i) any untrue or alleged untrue statement of material fact contained, on
the effective date thereof, in any registration statement, prospectus or
preliminary prospectus or any amendment thereof or supplement thereto, (ii) any
omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading or
(iii) any violations by such Person of any federal, state or common law rule or
regulation applicable to such Person and relating to action required of or
inaction by such Person in connection with any such registration; provided that
with respect to a Claim arising pursuant to clause (i) or (ii) above, the
material misstatement or omission is contained in or omitted from such Seller's
Information; provided, further, that the obligation to indemnify shall be
limited to the net amount of proceeds received by such Holder from the sale of
Registrable Securities pursuant to such registration statement.

            (c) Any Person entitled to indemnification hereunder shall (i) give
prompt written notice to the indemnifying party of any claim with respect to
which it seeks indemnification (but the failure to provide such notice shall not
release the indemnifying party of its obligation under paragraphs (a) and (b),
unless and then only to the extent that the indemnifying party has been
materially prejudiced by such failure to provide such notice) and (ii) unless in
such indemnified


                                       9
<Page>

party's reasonable judgment a conflict of interest between such indemnified and
indemnifying parties exists with respect to such claim, permit such indemnifying
party to assume the defense of such claim with counsel reasonably satisfactory
to the indemnified party. An indemnifying party who is not entitled to, or
elects not to, assume the defense of a claim shall not be obligated to pay the
fees and expenses of more than one counsel, excluding local counsel, for all
parties indemnified by such indemnifying party with respect to such claim,
unless in the reasonable judgment of any indemnified party a conflict of
interest exists between such indemnified party and any other of such indemnified
parties with respect to such claim.

            (d) The indemnifying party shall not be liable to indemnify an
indemnified party for any settlement, or consent to judgment of any such action
effected without the indemnifying party's consent (but such consent shall not be
unreasonably withheld). Furthermore, the indemnifying party shall not, except
with the approval of each indemnified party, consent to entry of any judgment or
enter into any settlement that does not include as an unconditional term thereof
the giving by the claimant or plaintiff to each indemnified party of a release
from all liability in respect to such claim or litigation without any payment or
consideration provided by each such indemnified party.

            (e) If the indemnification provided for in this Section 7 is
unavailable to an indemnified party under clauses (a) and (b) above in respect
of any losses, claims, damages or liabilities 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 or liabilities in such proportion as is
appropriate to reflect the relative fault of the Company, the underwriters, the
sellers of Registrable Securities and any other sellers participating in the
registration statement in connection with the statement or omissions that
resulted in such losses, claims, damages or liabilities. The relative fault of
the Company, the underwriters, the sellers of Registrable Securities and any
other sellers participating in the registration statement shall be determined by
reference to, among other things, whether the untrue or alleged untrue statement
of a material fact or the omission or alleged omission to state a material fact
relates to information supplied or omitted by the Company or by a Holder for use
in registration statement and the parties' relative intent, knowledge, access to
information and opportunity to correct or prevent such statement or omission.

            (f) The indemnification provided for under this Agreement shall
remain in full force and effect regardless of any investigation made by or on
behalf of the indemnified party or any officer, director or controlling person
of such indemnified party and shall survive the transfer of securities.


                                       10
<Page>

            8. PARTICIPATION IN UNDERWRITTEN REGISTRATIONS. No Person may
participate in any registration hereunder which is underwritten unless such
Person (a) agrees to sell such Person's securities on the basis provided in any
underwriting arrangements approved by the Person or Persons entitled hereunder
to approve such arrangements, (b) as expeditiously as possible notifies the
Company of the occurrence of any event as a result of which such prospectus
contains an untrue statement of material fact or omits to state a material fact
required to be stated therein or necessary to make the statements therein not
misleading and (c) completes and executes all questionnaires, powers of
attorney, indemnities, underwriting agreements and other documents reasonably
required under the terms of such underwriting arrangements.

            9. INFORMATION BY HOLDER. Each Holder shall fiunish the Company such
written information regarding such Holder and any distribution proposed by such
Holder as the Company may reasonably request in writing and as shall be
reasonably required in connection with any registration, qualification or
compliance referred to in this Agreement.

            10. EXCHANGE ACT COMPLIANCE. After the effectiveness of a
registration statement, the Company shall comply with all the reporting
requirements of the Exchange Act applicable to them and shall comply with all
other public information reporting requirements of the Commission that are
conditions to the availability of Rule 144 for the sale of the Registrable
Securities. The Company shall cooperate with each Holder in supplying such
information as may be necessary for such Holder to complete and file any
information reporting forms currently or hereafter required by the Commission as
a condition to the availability of Rule 144.

            11. LIMITATION ON REGISTRATION. The Company shall not be obligated
to effect a registration of any Holder's Registrable Securities pursuant to
Sections 2 or 3 hereof if all the Registrable Securities have been sold under
Rule 144, Regulation S or similar provision under the Securities Act so that
there is no further restriction on the transfer by the transferee or the
Holder's shares of Common Stock no longer constitute Registrable Securities. The
Company shall not be required to include any Registrable Securities of a Holder
in a registration if all such Holder's Registrable Securities could be sold
within a three month period pursuant to Rule 144 or other similar rule or
regulation.

            12. MISCELLANEOUS.

            (a) NO INCONSISTENT AGREEMENTS. The Company shall not hereafter
enter into any agreement with respect to its securities that is inconsistent
with or violates the rights granted to Holders in this Agreement without the
prior written consent of a majority in interest of such Registrable Securities.

            (b) REMEDIES. Any Person having rights under any provision of this
Agreement shall be entitled to enforce such rights specifically to recover
damages caused by reason of any


                                       11
<Page>

breach of any provision of this Agreement and to exercise all other rights
granted by law. The parties hereto agree and acknowledge that money damages may
not be an adequate remedy for any breach of the provisions of this Agreement and
that any party may in its sole discretion apply to any court of law or equity of
competent jurisdiction (without posting any bond or other security) for specific
performance and for other injunctive relief in order to enforce or prevent
violation of the provisions of this Agreement; provided that in no event shall
any Holder have the right to enjoin or interfere with any offering of securities
by the Company.

            (c) AMENDMENTS AND WAIVERS. Except as otherwise provided herein, the
provisions of this Agreement may be amended or waived only upon the prior
written consent of the Company and a majority in interest of the Holders.

            (d) SUCCESSORS AND ASSIGNS. All covenants and agreements in this
Agreement by or on behalf of any parties hereto shall bind and inure to the
benefit of the parties hereto and their respective successors and permitted
assigns. Prior to any transfer of Registrable Securities (or securities
convertible into, exercisable or exchangeable for Registrable Securities) the
transferring Holder shall provide written notice to the Company and consider any
reasonable objections raised by the Company within 10 business days of receipt
of such notice, provided that the Holder retains the right to proceed with such
transfer and provided further that a transfer of the rights contained herein
shall not be valid unless the transferee agrees in writing to be bound by terms
of this Agreement. In addition, whether or not any express assignment has been
made, the provisions of this Agreement that are for the benefit of Holders are
also for the benefit of, and enforceable by, any permitted transferee of
Registrable Securities.

            (e) SEVERABILITY. Whenever possible, each provision of this
Agreement shall be interpreted in such manner as to be effective and valid under
applicable law, but if any provision of this Agreement is held to be prohibited
by or invalid under applicable law, such provision shall be ineffective only to
the extent of such prohibition or invalidity, without invalidating the remainder
of this Agreement.

            (f) SUPERCEDING AGREEMENT. The parties agree that the First Closing
Agreement shall be superceded by this Agreement and of no further effect.

            (g) COUNTERPARTS. This Agreement may be executed simultaneously in
two or more counterparts, any one of which need not contain the signatures of
more than one party, but all such counterparts taken together shall constitute
one and the same Agreement.

            (h) DESCRIPTIVE HEADINGS. The descriptive headings of this Agreement
are inserted for convenience only and do not constitute a part of this
Agreement.

            (i) GOVERNING LAW. This Agreement shall be governed by and construed
in


                                       12
<Page>

accordance with the laws of the State of New York.

            (j) NOTICES. Any notice required or permitted hereunder shall be
given in writing and shall be deemed effectively given (a) upon personal
delivery, (b) five days after deposit in the United States mail, by certified
mail, postage prepaid, return receipt requested, (c) on the next business day
after deposit with a recognized overnight delivery service or (d) upon written
confirmation of facsimile transmission during regular business hours followed by
delivery of the document in one of the foregoing manners, in each case
addressed:

      If to the Company:      Continental Plaza
                              433 Hackensack Avenue
                              Hackensack, New Jersey 07601
                              Attn: Chief Executive Officer

       With a copy to:        Goodwin Procter & Hoar LLP
                              599 Lexington Avenue - 40th Floor
                              New York, New York 10022
                              Attn: J. Robert Horton

       If to Holders, at:     c/o BVF Partners, L.P.
                              One Sansome Street, 39th Floor
                              SanFrancisco, California 94104
                              Attn: Mark Lampert

       With a copy to:        Jones, Day, Reavis & Pogue
                              901 Lakeside Avenue
                              Cleveland, Ohio 44114
                              Attn: Christopher Kelly

      or at such other address as the Company or Holders may designate by 10
      days' advance written notice to Holders or the Company.

            (k) TERMINATION. This Agreement shall terminate as to a Holder on
the date as of which such Holder does not have any Registrable Securities.


                                       13
<Page>

            IN WITNESS WHEREOF, the parties have executed this Registration
Rights Agreement as of the date first written above.

                                  DOV PHARMACEUTICAL, INC.

                                  By: /s/ Bernard Beer
                                      ------------------------------------------
                                      Name:  Bernard Beer
                                      Title:  President


                                  BIOTECHNOLOGY VALUE FUND, L.P.
                                      By: BVF Partners L.P., its General Partner
                                      By: BVF Inc., its General Partner

                                  By:
                                      ------------------------------------------
                                      Mark Lampert, President


                                  BIOTECHNOLOGY VALUE FUND II, L.P.
                                      By: BVF Partners L.P., its General Partner
                                      By: BVF Inc., its General Partner

                                  By:
                                      ------------------------------------------
                                      Mark Lampert, President


                                  INVESTMENT 10 LLC

                                      By: BVF Partners L.P., Investment Advisor
                                      By: BVF Inc., its General Partner

                                  By:
                                      ------------------------------------------
                                      Mark Lampert, President


                                       14
<Page>

            IN WITNESS WHEREOF, the parties have executed this Registration
Rights Agreement as of the date first written above.

                                  DOV PHARMACEUTICAL, INC.

                                  By:
                                      ------------------------------------------
                                      Name:  Bernard Beer
                                      Title:  President


                                  BIOTECHNOLOGY VALUE FUND, L.P.
                                      By: BVF Partners L.P., its General Partner
                                      By: BVF Inc., its General Partner

                                  By: /s/ Mark Lampert
                                      ------------------------------------------
                                      Mark Lampert, President


                                  BIOTECHNOLOGY VALUE FUND II, L.P.
                                      By: BVF Partners L.P., its General Partner
                                      By: BVF Inc., its General Partner

                                  By: /s/ Mark Lampert
                                      ------------------------------------------
                                      Mark Lampert President


                                  INVESTMENT 10 LLC

                                      By: BVF Partners L.P., Investment Advisor
                                      By: BVF Inc., its General Partner

                                  By: /s/ Mark Lampert
                                      ------------------------------------------
                                      Mark Lampert, President


                                       14
<Page>

                                  /s/ Matthew Perry
                                  ----------------------------------------------
                                  MATTHEW PERRY


                                  RESERVOIR CAPITAL PARTNERS, L.P.
                                     By: Reservoir Capital Group, L.L.C.,
                                         general partner

                                  By:
                                      ------------------------------------------
                                  Name:
                                  Title: Managing Director


                                  RESERVOIR CAPITAL MASTER FUND, L.P.
                                     By: Reservoir Capital Group, L.L.C.,
                                         general partner

                                  By:
                                      ------------------------------------------
                                  Name:
                                  Title: Managing Director


                                  RESERVOIR CAPITAL ASSOCIATES, L.P.

                                  By:
                                      ------------------------------------------
                                  Name:
                                  Title: Managing Director


                                       15
<Page>

                                  ----------------------------------------------
                                  MATTHEW PERRY


                                  RESERVOIR CAPITAL PARTNERS, L.P.
                                     By: Reservoir Capital Group, L.L.C.,
                                         general partner

                                  By: /s/ Gregg Zeitlin
                                      ------------------------------------------
                                  Name:  Gregg Zeitlin
                                  Title: Managing Director


                                  RESERVOIR CAPITAL MASTER FUND, L.P.
                                     By: Reservoir Capital Group, L.L.C.,
                                         general partner

                                  By: /s/ Gregg Zeitlin
                                      ------------------------------------------
                                  Name:  Gregg Zeitlin
                                  Title: Managing Director


                                  RESERVOIR CAPITAL ASSOCIATES, L.P.

                                  By: /s/ Gregg Zeitlin
                                      ------------------------------------------
                                  Name:  Gregg Zeitlin
                                  Title: Managing Director


                                       15
<Page>

                                   SCHEDULE 1
                             FIRST CLOSING INVESTORS

Biotechnology Value Fund, L.P.
Biotechnology Value Fund II, L.P.
Investment 10 LLC
Matthew Perry


                                       16
<Page>

                                   SCHEDULE 2
                            SECOND CLOSING INVESTORS

Reservoir Capital Partners, L.P.
Reservoir Capital Master Fund, L.P.
Reservoir Capital Associates, L.P.


                                       17