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Exhibit 10.28

***Text Omitted and Filed Separately
Confidential Treatment Requested
Under 17 C.F.R. §§ 200.80(b)(4)
and 240.24B-2

LETTER AGREEMENT

        THIS LETTER AGREEMENT (this "Agreement") is entered into as of
January 9, 2004 (the "Effective Date") by and among FOREST LABORATORIES IRELAND
LIMITED, an Irish corporation ("Forest"), having offices at Clonshaugh
Industrial Estate, Clonshaugh, Dublin 17, Republic of Ireland, CYPRESS
BIOSCIENCE, INC., a Delaware corporation ("Cypress"), having offices at 4350
Executive Drive, Suite 325, San Diego, CA 92121 and PIERRE FABRE MÉDICAMENT,
organized under the laws of France ("Pierre Fabre"), having offices at 45, place
Abel-Gance, 92654 Boulogne Cedex, France.

RECITALS

        WHEREAS, Cypress and Pierre Fabre have entered into the Third Restated
License Agreement as of the date hereof, as may be amended (the "License
Agreement"), the First Restated Trademark License Agreement dated as of the date
hereof, as may be amended (the "Trademark Agreement"), and the Purchase and
Supply Agreement as of the date hereof, as may be amended (the "Supply
Agreement"), a copy of each of which has been provided to Forest, pursuant to
which Pierre Fabre has granted to Cypress an exclusive license to develop and
commercialize Licensed Product (as defined in the License Agreement, except as
otherwise noted herein) and Pierre Fabre will supply to Cypress and its
sub-licensees, and Cypress and its sub-licensees will purchase from Pierre
Fabre, Bulk API (as defined in the Supply Agreement);

        WHEREAS, Forest and Cypress are entering into a License and
Collaboration Agreement as of the date hereof, as may be amended, modified or
restated from time to time (the "Collaboration Agreement"), pursuant to which,
among other things, Cypress is granting to Forest an exclusive sub-license under
the rights granted to Cypress by Pierre Fabre under the License Agreement and
the Trademark Agreement in the Licensed Territory (as defined in the
Collaboration Agreement), all on the terms and conditions set forth in the
Collaboration Agreement; and

        WHEREAS, Forest, Cypress and Pierre Fabre are entering into this
Agreement in order to govern the relationship among Forest, Cypress and Pierre
Fabre under certain provisions of the Supply Agreement, the License Agreement
and the Trademark Agreement.

AGREEMENT

        NOW, THEREFORE, in consideration of the foregoing premises and the
mutual covenants and agreements contained herein and other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties hereto agree as follows:

1.     SUPPLY; FORECASTS

        1.1    Supply of Bulk API.    The parties agree that, until Pierre Fabre
is otherwise notified in writing by Cypress in connection with a termination of
Forest's rights under the Collaboration Agreement, Pierre Fabre will manufacture
and supply directly to Forest, and Forest will purchase directly from Pierre
Fabre, Bulk API for the Licensed Territory on the terms set forth in the Supply
Agreement, including, without limitation, Sections 2.1, 2.2, 6 and 7.4.

        1.2    Forecasts.    Forest will provide directly to Pierre Fabre, with
a copy to Cypress, (a) Sales Forecasts (as defined in the License Agreement) for
the Licensed Territory on the terms set forth in the License Agreement, and
(b) Delivery Forecasts and Purchase Orders (both as defined in the Supply
Agreement) for the Licensed Territory on the terms set forth in the Supply
Agreement, including,

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without limitation, Section 4.1; provided that such Sales Forecasts, Delivery
Forecasts and Purchase Orders have first been reviewed and agreed to between
Cypress and Forest to the extent such Sales Forecasts, Delivery Forecasts and
Purchaser Orders impose obligations on Cypress.

        1.3    Independence of Supply Commitment.    Pierre Fabre agrees that
the terms and conditions of the Supply Agreement with respect to Delivery
Forecasts, Purchase Orders, Pierre Fabre's supply commitment and otherwise shall
be determined and applied separately with respect to each of Forest and Cypress
(including any other sub-licensee of Cypress under the License Agreement) if and
to the extent Cypress (including any other sub-licensee of Cypress under the
License Agreement) purchases Bulk API for use in Canada.

2.     SUB-LICENSE RIGHTS

        2.1    Licensed Technology and Trademarks.    Forest may further
sub-license the rights in the Licensed Technology (as defined in the License
Agreement) and the Trademarks (as defined in the Trademark Agreement) and the
rights under the Supply Agreement granted to it by Cypress under the
Collaboration Agreement as follows.

        (a)   Forest may grant such a sub-license in the Licensed Territory to
Forest Laboratories, Inc., a Delaware corporation ("Forest Parent"), or any of
Forest Parent's wholly owned subsidiaries with prior written notice to Pierre
Fabre.

        (b)   Should Forest decide to grant such a sub-license in a given
country within the Licensed Territory to any person or entity other than to
Forest Parent or any of Forest Parent's wholly-owned subsidiaries, then Forest
shall provide Pierre Fabre written notice thereof (the "Sub-license Notice")
before offering such sub-license to any other person or entity, and hereby
grants Pierre Fabre a right of first discussion to take such sub-license, and
upon Pierre Fabre's request, shall enter into good faith negotiations with
Pierre Fabre to grant such sub-license to Pierre Fabre or any Affiliate (as
defined in the License Agreement) of Pierre Fabre in such country. If Pierre
Fabre does not notify Forest of its interest in obtaining such a sub-license in
the applicable country within 30 days from receipt of the Sub-license Notice,
then Forest shall be free to grant such sub-license to any other person or
entity in the applicable country, subject to the prior written consent of Pierre
Fabre, which shall not be unreasonably withheld or delayed. In the event that
Pierre Fabre is interested in obtaining such a sub-license, it shall notify
Forest in writing within 30 days after receipt of the Sub-license Notice and the
parties shall negotiate in good faith for up to 60 days from the date of the
Sub-license Notice (the "Negotiation Period"). If Forest and Pierre Fabre fail
to enter into a definitive agreement granting Pierre Fabre such sub-license
rights within such 60 day negotiation period despite mutual efforts by Forest
and Pierre Fabre to reach agreement, it shall be deemed to constitute rejection
by Pierre Fabre of such right and, in such event or if the Negotiation Period
expires without Forest and Pierre Fabre entering into a definitive agreement,
then Forest shall be free to grant such sub-license rights to any other person
or entity in the applicable country, subject to the prior written consent of
Pierre Fabre, which shall not be unreasonably withheld or delayed.

3.     PAYMENTS

        3.1    Transfer Price.    Forest will pay directly to Pierre Fabre the
Transfer Price (as defined in the Supply Agreement) for all Bulk API purchased
under the Supply Agreement with respect to the Licensed Territory in accordance
with the terms of Section 5 of the Supply Agreement, except that the obligation
of Cypress to make payment to Pierre Fabre under Section 5.1(a)(ii)(2) will
apply only to Cypress and not to Forest. Forest will notify Cypress of such
payments made by Forest to Pierre Fabre.

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        3.2    Royalties.    Forest will pay directly to Pierre Fabre the
royalty payments required under Sections 6.4(a), (b) and (c) of the License
Agreement and Section 1.10 of the Trademark Agreement with respect to the
Licensed Territory in accordance with the respective terms of the License
Agreement and the Trademark Agreement; provided that no royalty shall be due
from Forest to Pierre Fabre under Section 6.4(a) of the License Agreement by
Forest with respect to the SR Formulation Patent, Ref: 09/254 014 included in
the Pierre Fabre Patents (as defined in the License Agreement). Forest agrees
that it shall notify Cypress of such payments to Pierre Fabre.

        3.3    Payment for Canada.    Pursuant to Sections 3.1 and 5.2 of the
License Agreement, and Section 2.5 of the Collaboration Agreement, Pierre Fabre
acknowledges that the decision whether or not to develop, register and launch
Licensed Product in Canada, and the timing of any such decision, shall be
subject to the good faith business judgment of Forest; provided however, if
Forest does not exercise its right to extend the Licensed Territory under
Section 2.5 of the Collaboration Agreement to include Canada prior to the
expiration of [...***...] (i) Forest shall have no further rights with respect
to Canada under this Letter Agreement, the Collaboration Agreement or the
License Agreement and (ii) Cypress' obligations under Section 5.2 of the License
Agreement shall remain in full force and effect. In the event Forest does
exercise its right to extend the Licensed Territory under Section 2.5 of the
Collaboration Agreement to include Canada and subsequently determines not to
launch Licensed Product in Canada, promptly following such determination,
(a) Forest shall pay to Pierre Fabre [...***...] (the "Canadian Payment") and
(b) Cypress shall pay to Pierre Fabre the [...***...] Promptly following such
determination by Forest, Forest will make a good faith calculation of the
Canadian Payment and will provide such calculation to Pierre Fabre, with a copy
to Cypress. Pierre Fabre will review such calculation and will notify Forest in
writing, with a copy to Cypress, within 30 days of the date Forest provided such
calculation if Pierre Fabre has any questions regarding, or objects to, the
Forest calculation. If Pierre Fabre does not provide such written notice within
such 30-day period, Forest shall [...***...] If Pierre Fabre provides such
written notice to Forest within such 30-day period, then Forest and Pierre shall
negotiate in good faith regarding [...***...] If such negotiation requires that
Pierre Fabre [...***...] then Forest and Pierre Fabre shall select one expert
with relevant industry experience to review such information in connection with
[...***...] provided that, if the parties cannot agree on one expert, then a
panel of three experts with relevant industry experience shall be formed for
such purpose, with one expert being chosen by Forest, one expert being chosen by
Pierre Fabre and one expert being chosen by the two experts chosen by Forest and
Pierre Fabre. The expert or the panel of experts, as applicable, must be chosen
within 30 days from notice by either Forest or Pierre Fabre regarding the need
to appoint such expert or panel of experts. Any such expert or panel of experts
shall enter into a confidential disclosure agreement with Forest and Pierre
Fabre containing commercially reasonable terms for protection of proprietary
information provided by Forest and Pierre Fabre. Pierre Fabre shall provide such
expert or panel of experts information regarding Pierre Fabre's [...***...]
Forest shall provide such expert or panel of experts such additional information
used by Forest in [...***...] as is necessary to use the information regarding
[...***...] The expert or panel of experts shall review such information
provided by Forest and Pierre Fabre, use such information in [...***...] and
provide the parties with the result of such calculation for use in the Canadian
Payment within 30 days from the selection of the expert or the last expert on
the panel, as applicable. The parties acknowledge that in no event shall the
panel share any information regarding Pierre Fabre's [...***...] with Forest and
Cypress. Forest and Pierre Fabre shall each pay 50% of the costs of engaging the
expert or panel of experts under this Section 3.3. Forest may, at its option
upon written notice to Pierre Fabre, pay the Canadian Payment either in a lump
sum payment based on the net present value of the Canadian Payment as of the
date of such payment (calculated at the applicable LIBOR rate of interest as
reported in The Wall Street Journal (absent any error) on the date of the
determination of the Canadian Payment pursuant to this Section 3.3) or in
payments made on a quarterly basis over no more than five years, as designated
by Forest. Forest will notify Cypress of such payments made by Forest to Pierre
Fabre.

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        3.4    Royalty from Forest to Pierre Fabre; Sharing of Royalty with
Cypress.    

        (a)   If, during the Exclusive Period (as defined in the Collaboration
Agreement), Forest or any of its Affiliates (as defined in the Collaboration
Agreement), licensees, or sub-licensees markets or sells any product (other than
(i) Licensed Product, as defined in the Collaboration Agreement, (ii) SNRI
product, as defined in the License Agreement, which shall be subject to
Section 3.5 or 3.7 of this Agreement, as applicable, or (iii) Forest Product, as
defined in the License Agreement, which shall be subject to Section 5.4(c) of
the Collaboration Agreement) for FMS (as defined in the Collaboration Agreement)
in the Licensed Territory using any Information developed or generated, or
disclosed by Cypress to Forest, in the course of performance of the
Collaboration Agreement, Forest will pay Pierre Fabre a royalty of [...***...]
on net sales of such product; provided that such amount may be reduced by
written agreement of Pierre Fabre and Forest to account for any royalty payments
that Forest or its licensees must make to any third parties with respect to such
product. Such royalty shall be payable for the Exclusive Period, but in any
event, the payment term shall not be less than [...***...], and the payment
terms of Section 10 of the Collaboration Agreement shall apply with respect to
such royalty. This Section 3.4(a) shall not restrict Forest from conducting
clinical trials in FMS of any product being developed by Forest for neuropathic
pain indications as of the Effective Date, including, without limitation, the
compounds [...***...] if such clinical trials in FMS are required by the FDA for
the NDA submission for such product, and no royalty shall be payable pursuant to
this Section with respect to such product.

        (b)   Cypress shall pay to Pierre Fabre [...***...] of any royalty
payment received by Cypress from Forest under Section 5.4(b) of the
Collaboration Agreement within 15 days following the receipt of such payment
from Forest (or will direct Forest to deduct such amount from the royalty
payment otherwise due to Cypress under Section 5.4(b) of the Collaboration
Agreement and pay such amount directly to Pierre Fabre).

        3.5    Royalty to Pierre Fabre on New Product; Right of First
Negotiation to Supply Bulk API for New Product.    

        (a)   Notwithstanding Section 3.7 of this Agreement, Forest or any of
its Affiliates or sub-licensees may market and sell any product containing an
analog of Milnacipran that is subject to the Collaboration Agreement, which
product is an SNRI product (as defined in the License Agreement) (a "New
Product"), in the Licensed Territory (as defined in the Collaboration Agreement)
before the requirement under Section 3.7 expires in accordance with its terms
(the "End Date"), subject to compliance with this Section 3.5.

        (b)   If, at any time before the End Date, Forest or any of its
Affiliates or sub-licensees markets or sells any New Product in the Licensed
Territory, then, from the time such New Product is first commercialized until
the End Date, Forest will pay Pierre Fabre [...***...] (such royalty payment,
the "New Product Royalty").

        (c)   If, at any time before the End Date, Forest or any of its
Affiliates or sub-licensees plans to market or sell any New Product in the
Licensed Territory, then Forest shall provide Pierre Fabre written notice
[...***...] prior to the production of the first clinical batch of active
pharmaceutical ingredient of such New Product (the "New Product Notice") and
hereby grants Pierre Fabre a first right to negotiate an agreement with Forest
and Cypress (the "New Supply Agreement") to supply the active pharmaceutical
ingredient contained in such New Product ("New Product API"). Such right of
first negotiation shall also apply to industrial development and scale-up of the
manufacturing process with respect to New Product API if Forest decides to
contract with a third party with respect to such activities rather than to
conduct such activities itself or through one of its Affiliates. Upon Pierre
Fabre's request, provided in writing to Forest and Cypress within 30 days after
the date of the New Product Notice, Forest and Cypress shall enter into good
faith

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negotiations with Pierre Fabre regarding the New Supply Agreement. If Pierre
Fabre does not provide such notice of its interest in obtaining such right
within 30 days from the date of the New Product Notice, then Forest and Cypress
shall be free to negotiate and enter into an agreement to purchase New Product
API from any other person or entity. In the event that Pierre Fabre provides
such notice of its interest in entering into the New Supply Agreement within
30 days after receipt of the New Product Notice, Pierre Fabre, Cypress and
Forest shall negotiate the New Supply Agreement in good faith for up to 60 days
from the date of the written notice from Pierre Fabre (the "Negotiation
Period"). Cypress, Forest and Pierre Fabre agree that the general commercial
terms and conditions of the Supply Agreement shall be used as a model of
commercially reasonable terms when negotiating the New Supply Agreement. If
Cypress, Forest and Pierre Fabre fail to enter into the New Supply Agreement
within the Negotiation Period despite good faith efforts to reach agreement,
then Cypress and Forest shall be free to negotiate and enter into an agreement
to purchase New Product API from any other person or entity; provided, however,
that if the proposed supply agreement with such other person or entity provides
for principal economic terms (including, without limitation, transfer price and
supply term, assuming comparable quality and quantity) that are more favorable
to such other person or entity than those principal economic terms last proposed
by Cypress and Forest to Pierre Fabre, Forest will first give Pierre Fabre
written notice of such more favorable terms and Pierre Fabre shall have the
first right to enter into a New Supply Agreement with Cypress and Forest on
those terms set forth in such notice, which right Pierre Fabre may exercise upon
written notice to Cypress and Forest provided within 15 days after the date of
such notice from Forest. If Pierre Fabre does not exercise such right by
providing such written notice within such 15-day period, then Cypress and Forest
shall be free to enter into the proposed supply agreement with such other person
or entity.

        (d)   In the event Pierre Fabre and Forest do not enter into the New
Supply Agreement after negotiating in good faith to enter into the New Supply
Agreement as contemplated under Section 3.5(c), then from the time such New
Product is first commercialized until the End Date, Forest will pay Pierre Fabre
[...***...] ("Additional New Product Payment").

        (e)   Cypress and Forest will share the amount of any New Product
Royalty and any Additional New Product Payment paid by Forest to Pierre Fabre
under Section 3.5(b) or Section 3.5(d), [...***...] and Forest may deduct an
amount equal to Cypress' share of any such New Product Royalty or Additional New
Product Payment paid by Forest to Pierre Fabre from royalty payments otherwise
due from Forest to Cypress under Section 6.4(a) of the Collaboration Agreement;
provided that such royalties will not be reduced by more than [...***...] in any
quarter as a result of any such deduction.

        (f)    If a payment is made to Pierre Fabre with respect to any New
Product, then no payment shall be due or payable to Pierre Fabre under
Section 5.4(b) of the License Agreement on net sales of such New Product,
notwithstanding anything to the contrary set forth in Section 5.4(b) of the
License Agreement.

        3.6    Sharing with Forest of Payments Made by Pierre Fabre to
Cypress.    Cypress will pay to Forest a share of the amount of any royalty paid
to Cypress by Pierre Fabre on certain products for FMS in the Licensed Territory
(as defined in the Collaboration Agreement) pursuant to Section 5.4(b) of the
License Agreement, based on [...***...] In addition, Cypress will pay to Forest
[...***...]

        3.7    SNRI Products.    During the period from the Effective Date until
the earlier of (i) the Date of First Commercial Sale of the first Generic
Product (each as defined in the License Agreement) or (ii) the last day of the
License Term (as defined in the License Agreement), if any of Pierre Fabre,
Cypress or Forest (or any Affiliate, licensee or sub-licensee of such party with
respect to an SNRI product) wishes to develop any SNRI product (as defined in
the License Agreement), including, without limitation, the [...***...]
Milnacipran [...***...] (the "Pierre Fabre [...***...]") and any New

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Product (subject to Section 3.7(d)), but excluding Licensed Product (as defined
in the License Agreement), for use in the Licensed Territory, such party shall
be subject to the following:

        (a)   It shall not study, develop, register, use, distribute, offer for
sale, sell, have sold or import such SNRI product for any of the indications of
FMS, chronic fatigue syndrome, attention deficit/hyperactivity disorder,
visceral pain syndromes, functional somatic syndromes, cognitive dysfunction (to
the extent not associated with depression), sleep disorders (to the extent not
associated with depression), irritable bowel syndrome, chronic lower back pain,
chronic pelvic pain, interstitial cystitis, non-cardiac chest pain, neuropathic
pain, temporomandibular joint disorder, atypical face pain, tension headaches,
multiple chemical sensitivities, chronic pain associated with drug or radiation
therapy or other chronic pain indications (the "Milnacipran Indications") for
which Licensed Product has received regulatory approval or is in active
development anywhere in the Licensed Territory during the License Term (as
defined in the License Agreement).

        (b)   Subject to Section 3.7(a), it shall not launch such SNRI product
in any country within the Licensed Territory for any indication until
[...***...] following the Date of First Commercial Sale of the Licensed Product
within each such country; provided that such restriction shall not prevent the
launch of such SNRI product at any time after [...***...] In addition, upon
launch of any SNRI product in accordance with this Section 3.7(b), such party
shall use commercially reasonable efforts to prevent any use of such SNRI
product in any Milnacipran Indication.

        (c)   If such SNRI product is launched in any country within the
Licensed Territory for any indication other than a Milnacipran Indication in
accordance with Section 3.7(b), and if such SNRI product is prescribed based on
a primary diagnosis of a Milnacipran Indication for which Licensed Product has
received regulatory approval, the provisions of this Section 3.7(c) shall apply:

          (i)  The party selling the SNRI product (the "Reimbursing Party") will
reimburse each other party (each a "Reimbursed Party") for the economic benefit
that the Reimbursed Party would have realized had such sales of the SNRI product
for use in the Milnacipran Indication been sales of Licensed Product instead of
the SNRI product as determined in accordance with this Section 3.7(c); provided,
however, that no such reimbursement shall be made to any party to the extent
such party has an economic interest in sales of such SNRI product other than by
virtue of this Section 3.7(c). Such economic benefit shall be calculated based
on, and to the extent of prescriptions for the SNRI product reflecting a primary
diagnosis of a Milnacipran Indication. Such economic benefit shall be calculated
to be (A) if the Reimbursed Party's interest consists of royalties from, or
sales of active pharmaceutical ingredient to, another party hereto, the amount
of such royalties which such party would have otherwise received, or the sales
price it would have otherwise received from such sales of active pharmaceutical
ingredient less direct manufacturing costs, and (B) if such Reimbursed Party's
interest consists, directly or indirectly through a licensee or Affiliate, of
the marketing of a finished pharmaceutical product, the net sales of such
finished pharmaceutical product (whether made by such party, an Affiliate or a
licensee which is not another party hereto or an Affiliate of any such party),
less the cost of goods and distribution costs related to such net sales;
provided that in no event shall the economic benefit to be reimbursed to the
Reimbursed Party exceed the economic benefit of the Reimbursing Party (including
the economic benefit to any licensee of such party which is not a party hereto
or an Affiliate of a party hereto) derived from the SNRI product in question,
with such economic benefit to be calculated in the same manner as described
above. If, due to the applicability of the proviso at the end of the immediately
preceding sentence, the actual amount to be reimbursed to the Reimbursed Parties
under this Section 3.7(c) is less than the actual economic benefit to the
Reimbursed Parties that would have been realized had such sales of the SNRI
product for use in the Milnacipran Indication been sales of Licensed Product
instead of the SNRI product, then the amount to be

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reimbursed to the Reimbursed Parties will be shared by the Reimbursed Parties in
proportion to the actual economic benefit that each such Reimbursed Party lost.

         (ii)  In the event that any Reimbursed Party believes that it is
entitled to reimbursement under this Section 3.7(c), it will provide the
Reimbursing Party written notice claiming reimbursement from the Reimbursing
Party under this Section 3.7(c), specifying the amount of the reimbursement and
supporting data regarding the number of prescriptions for use of the SNRI
product based on a primary diagnosis for an applicable Milnacipran Indication,
as reported by an appropriate data service such as National Disease and
Therapeutic Index (NDTI) or Verispan Physician Drug and Diagnosis Audit, which
was used to calculate the amount of the reimbursement (the "Report"). If
possible, the Reimbursed Parties will attempt to coordinate their claims for
reimbursement under this Section 3.7. The Reimbursing Party shall have up to
90 days after the date of such notice (the "Review Period") to review the
information provided in the notice from the Reimbursed Party. In the event that
the Reimbursing Party agrees with the amount of the reimbursement, it shall
promptly reimburse the Reimbursed Party for such amount. The Reimbursing Party
may, at any time during the Review Period, provide written notice to the
Reimbursed Party that it wishes to have an independent third party market
research firm conduct market research designed to collect accurate information
regarding the primary diagnosis that led to the prescription for the SNRI
product. The Reimbursing Party and Reimbursed Party will mutually agree on the
identity of the market research firm and the design of the market research plan.
The Reimbursing Party will bear the cost of conducting such market research
unless the results of such market research reflect that the actual number of
primary diagnoses that led to the prescription for the SNRI products exceeded
such number in the data originally provided by the Reimbursed Party by more than
5%, in which case the Reimbursed Party shall bear such cost. If the Reimbursing
Party and the Reimbursed Party cannot agree on these matters within 90 days
after notice from the Reimbursing Party requesting such market research be
conducted, then either party may request dispute resolution using an expert or
panel of experts according to the procedure described in Section 3.3. Without
limiting the foregoing, the parties agree that, if a Reimbursed Party does not
agree to disclose its direct manufacturing costs, the procedures set forth in
Section 3.3 will govern in respect to such costs.

       (iii)  Instead of the Reimbursed Party using data from a data service as
provided above, the Reimbursed Party may provide the Report and written notice
to the Reimbursing Party that it wishes to have an independent third party
market research firm conduct market research as the basis for determining the
amount of the reimbursement, in which case the design of such market research
will be subject to mutual agreement by the Reimbursing Party and the Reimbursed
Party and the Reimbursed Party will bear the cost of conducting the market
research.

        (iv)  The results of any market research conducted pursuant to this
Section 3.7(c) shall be binding on the Reimbursing Party and the Reimbursed
Party for purposes of calculating the amount of the reimbursement.

        (d)   If Forest and/or Cypress elect to develop the New Product for any
Milnacipran Indication, this Section 3.7 shall not apply to such New Product for
use in any such Milnacipran Indication and instead the provisions of Section 3.5
shall govern with respect to such New Product for use in any such Milnacipran
Indication.

        (e)   In consideration of Pierre Fabre agreeing to this Section 3.7,
Cypress hereby grants to Pierre Fabre a royalty-free, fully-paid, non-exclusive,
perpetual license, with the right to sub-license, under the Cypress Patents
entitled [...***...] to develop, register, use, distribute, sell, offer for sale
and have sold the Pierre Fabre [...***...] in the Licensed Territory for use
solely in depression,

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anxiety, panic and social phobia (but in no event for any other use, including,
without limitation, for any Milnacipran Indication).

4.     FORMULATIONS

        4.1    Grant to Pierre Fabre of License to Forest
Formulations.    Cypress and Pierre Fabre agree that the sub-licensegranted to
Forest under Section 2.1 of the Collaboration Agreement provides Forest with the
right to develop and commercialize its own new formulations of Licensed Product.
In the event Forest decides to develop and commercialize any new formulation of
Licensed Product ("Forest Formulation"), rather than the IR Formulation or SR
Formulation (as defined the Licensed Agreement), Forest will then notify Pierre
Fabre and Cypress of such Forest Formulation and Forest will grant to Pierre
Fabre a perpetual, royalty-free, exclusive license, with the right to
sub-license, under the applicable patents and patent applications owned by
Forest or its Affiliates (as defined in the Collaboration Agreement) claiming
such Forest Formulation, to develop, register, manufacture, use, distribute,
sell, offer for sale, have sold and import such Forest Formulation in the Rest
of the World (as defined in the License Agreement). The parties acknowledge and
agree that Forest Formulation expressly excludes any Cypress Formulation (as
defined in the Collaboration Agreement).

5.     FOREST AND CYPRESS OBLIGATIONS

        5.1    Promotion, Marketing and Sales Effort.    

        (a)   Forest agrees with Pierre Fabre to comply with Section 3.5(c) of
the Collaboration Agreement. If the Supply Agreement and the License Agreement
terminate as to Cypress but remain in place between Forest and Pierre Fabre,
then this Section 5.1, including Section 3.5(c) of the Collaboration Agreement
referred to herein, shall survive any termination of the Collaboration Agreement
as to Forest if and for so long as the Supply Agreement and the License
Agreement remain in place between Forest and Pierre Fabre.

        (b)   Cypress shall perform, or shall cause its sub-licensee to perform,
for the benefit of Pierre Fabre, the promotion, marketing and sales efforts set
forth in Section 3.5(c) of the Collaboration Agreement, as though such section
were set forth herein and "Cypress or its permitted sub-licensee" were
substituted for "Forest" therein. The obligations of Cypress pursuant to the
immediately preceding sentence shall survive the termination of this Agreement
and the Collaboration Agreement, but shall terminate immediately upon the
termination of the License Agreement as to Cypress. In the event Cypress
exercises the Promotion Right (as defined in Section 3.5(c) of the Collaboration
Agreement), the foregoing obligation of Cypress includes the minimum percentage
of the aggregate number of detailing calls to be made by the Cypress Sales Force
(as defined in the Collaboration Agreement) in the applicable fiscal year, which
obligation shall not apply to Forest.

        5.2    Forest Negotiation with Cypress and Pierre Fabre.    Forest shall
negotiate in good faith with Cypress and Pierre Fabre with regard to the matters
described in Section 5.4(c) of the Collaboration Agreement and Section 5.4(c) of
the License Agreement.

        6.    TERM.    The term of this Agreement shall commence on the
Effective Date and continue until the earlier of (i) the termination of the
Supply Agreement and the License Agreement; provided, however, that if, upon
termination of the Supply Agreement and the License Agreement, such agreements
remain in place between Pierre Fabre and Forest, this Agreement shall terminate
only as to Cypress, or (ii) upon receipt by Pierre Fabre of written notification
from Cypress and Forest of the termination of the Collaboration Agreement (the
"Term").

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7.     RECOGNITION

        7.1    Acknowledgement.    Pierre Fabre hereby acknowledges the
execution of the Collaboration Agreement and acknowledges that as of the
Effective Date, all rights of Pierre Fabre under Section 2.1(b) the License
Agreement to negotiate for rights to develop, register, market or sell Licensed
Product in the Licensed Territory have either been satisfied or waived.

        7.2    Representation.    Pierre Fabre hereby represents and warrants,
as of the Effective Date, that each of the License Agreement, Supply Agreement
and Trademark Agreement constitute legal and validly binding obligations of
Pierre Fabre, and are in full force and effect and enforceable in accordance
with their respective terms, and that, to its knowledge, no event has occurred
which would give Pierre Fabre the right to terminate or limit any of such
agreements or to seek damages or other legal or equitable remedies with respect
thereto.

        7.3    Recognition.    

        (a)   Notwithstanding anything to the contrary set forth in any of the
License Agreement, Supply Agreement or Trademark Agreement, Pierre Fabre
acknowledges and agrees that Forest is an intended third party beneficiary of
each of such agreements with full rights to enforce the provisions thereof to
the extent related to the Licensed Territory as if it were the original licensee
or purchasing party thereto. Without limiting the generality of the foregoing,
Forest shall be entitled to directly enforce the provisions of the License
Agreement, Supply Agreement and Trademark Agreement which provide for the
licenses of intellectual property, the supply of Bulk API, representations and
warranties of Pierre Fabre, confidentiality, indemnifications provided by Pierre
Fabre and requirements for the delivery of information and data by Pierre Fabre,
in each case to the extent related to the Licensed Territory and as if such
obligations provided by their specific terms for enforceability directly by
Forest. Pierre Fabre agrees to provide Forest with contemporaneous copies of all
information and notices which Pierre Fabre provides or is required to provide to
Cypress under such agreements to the extent related to the Licensed Territory
and, in particular, without limiting the generality of the foregoing, to provide
Forest with notices to be provided to Cypress under Exhibit C of the License
Agreement by the time such notices are to be provided to Cypress under such
Exhibit C.

        (b)   Notwithstanding anything to the contrary set forth in the
Collaboration Agreement, Forest acknowledges and agrees that Pierre Fabre is an
intended third party beneficiary of such agreement with full right to enforce
the provisions thereof to the extent related to the interest of Pierre Fabre as
such interest is defined by the License Agreement, Supply Agreement or Trademark
Agreement (the "Interest"). Without limiting the generality of the foregoing,
Pierre Fabre shall be entitled to directly enforce the provisions of the
Collaboration Agreement which provide for development, registration, sales and
marketing efforts of Forest, representations and warranties of Forest,
confidentiality, indemnifications provided by Forest and requirements for the
delivery of information and data by Forest, in each case to the extent related
to Pierre Fabre's Interest as if such obligations provided by their specific
terms for enforceability directly by Pierre Fabre. Forest agrees to provide
Pierre Fabre with contemporaneous copies of all information and notices which
Forest provides or is required to provide to Cypress under the Collaboration
Agreement to the extent related to Pierre Fabre's Interest.

        7.4    Amendments.    

        (a)   Cypress and Forest agree, without limitation of any of Pierre
Fabre's rights under Section 7.3(b), that any amendment to any of Sections 2.5,
2.6, 3.5(c), 5.3, 5.4(b) and 5.4(c) of the Collaboration Agreement or any of the
definitions in the Collaboration Agreement referenced in this Agreement shall
require the written consent of Pierre Fabre, which shall not be unreasonably
withheld in the event such amendment would not adversely affect Pierre Fabre's
Interest.

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        (b)   Cypress and Pierre Fabre agree that any amendment to any provision
of the License Agreement, Supply Agreement or Trademark Agreement that would
adversely affect Forest's interest therein as such interest is defined by the
Collaboration Agreement shall require the written consent of Forest.

        7.5    Survival of Agreements.    Any rights granted by Pierre Fabre to
Forest hereunder or under the License Agreement, Supply Agreement or Trademark
Agreement by reason of the Collaboration Agreement shall survive any termination
of such agreements for any reason, excepting only a termination as a result of
which Forest no longer possess rights to manufacture, market and distribute
Licensed Product for distribution in the Licensed Territory, and shall become
direct rights and obligations between Forest and Pierre Fabre, subject to the
respective terms of such agreements, including, without limitation, the
conditions for establishing a direct contractual relationship between Pierre
Fabre and Forest.

        7.6    Appointment of Forest Laboratories, Inc.    Forest shall
designate and appoint Forest Parent to perform all development, registration,
distribution and marketing obligations of Forest in the Licensed Territory
arising under the Collaboration Agreement (and, if Forest becomes a direct party
thereto or a licensee thereunder, under the License Agreement, Supply Agreement
or Trademark Agreement) and agrees to cause representatives of Forest Parent to
participate as representatives in all committees or working groups which may be
established from time to time under any of such agreements to the extent of
Forest's rights to participate in any such committees or working groups.

8.     GENERAL PROVISIONS.

        8.1    Dispute Resolution.    If the parties are unable to decide or
resolve any issue arising under this Agreement, except as expressly contemplated
in Section 3.3, the issue shall be referred to the Chief Executive Officers of
Pierre Fabre, Cypress and Forest (or any Affiliate of Forest that is primarily
responsible for the activities of Forest under the Collaboration Agreement, as
directed by Forest). Such officers of the parties shall meet promptly thereafter
and shall negotiate in good faith to resolve such issue. If they cannot resolve
the issue within 30 days of commencing such negotiations, the matter shall be
resolved by arbitration as provided in Section 8.2.

        8.2    Arbitration.    

        (a)   In the event of a dispute arising in connection with this
Agreement, except as expressly contemplated in Section 3.3, such dispute shall
be finally settled under the Rules of Conciliation and Arbitration (the "Rules")
of the International Chamber of Commerce (the "ICC") by three arbitrators.
Unless the parties otherwise agree in writing, the arbitration proceeding shall
be conducted and the arbitrators shall be appointed in accordance with the Rules
then in effect, subject to the procedures described in this Section 8.2.

        (b)   Any such arbitration proceeding shall commence by the delivery by
one party (the "Claimant") of a written notice requesting arbitration (the
"Request") to the other party or parties (each, a "Respondent"). The arbitration
proceedings shall take place in Toronto, Canada at the place mutually agreed
upon by the parties. Arbitration will be conducted in the English language.

        (c)   The Claimant shall appoint an arbitrator in the Request, and the
Respondent(s) shall appoint an arbitrator in its formal response to the Request
(the "Answer"). If a party fails to appoint an arbitrator or the Respondent(s)
fails to file its Answer within the time specified by the Rules, the ICC will
make the appointment. If only two of the parties are involved in such
arbitration, then (i) as soon as practicable after the date on which both of the
first two arbitrators have been appointed, but in any event within 30 days, the
two arbitrators will appoint the third arbitrator; (ii) if within such 30-day
period the first two arbitrators shall not have agreed on the appointment of the
third arbitrator, then the third arbitrator will be appointed by the ICC in

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accordance with the Rules; and (iii) the third arbitrator will serve as chair of
the tribunal. If all three of the parties are involved in such arbitration, then
(i) as soon as practicable after the date on which all three of the arbitrators
have been appointed, but in any event within 30 days, the three arbitrators will
appoint two additional arbitrators; (ii) if within such 30-day period the three
arbitrators shall not have agreed on the appointment of the two additional
arbitrators, then the two additional arbitrators will be appointed by the ICC in
accordance with the Rules; and (iii) the two additional arbitrators will serve
as co-chairs of the tribunal. The arbitration proceeding shall be completed
within 90 days after selection of the final arbitrator (subject to extension as
determined by the arbitrators).

        (d)   The arbitrators shall, within 15 calendar days after the
conclusion of the arbitration hearing, issue a written award and statement of
decision describing the essential findings and conclusions on which the award is
based, including the calculation of any damages awarded. The decision or award
rendered by the arbitrators shall be final and non-appealable, and judgment may
be entered upon it in accordance with applicable law in the State of New York or
any other court of competent jurisdiction. The arbitrators shall be authorized
to award compensatory damages, but shall NOT be authorized (i) to award
non-economic damages, such as for emotional distress, pain and suffering or loss
of consortium, (ii) to award punitive damages, or (iii) to reform, modify or
materially change this Agreement or any other agreements contemplated hereunder;
provided, however, that the damage limitations described in parts (i) and
(ii) of this sentence will not apply if such damages are statutorily imposed.

        (e)   Each party shall bear its own attorney's fees, costs, and
disbursements arising out of the arbitration, and shall pay an equal share of
the fees and costs of the arbitrators; provided, however, the arbitrators shall
be authorized to determine whether a party is the prevailing party, and if so,
to award to that prevailing party reimbursement for its reasonable attorneys'
fees, costs and disbursements (including, for example, expert witness fees and
expenses, photocopy charges, travel expenses, etc.), and/or the fees and costs
of the arbitrators.

        (f)    Unless the parties otherwise agree in writing, during the period
of time than any arbitration proceeding is pending under this Agreement, the
parties shall continue to comply with all those terms and provisions of this
Agreement that are not the subject of the pending arbitration proceeding.

        (g)   Nothing contained in this Agreement shall deny any party the right
to seek injunctive or other equitable relief from a court of competent
jurisdiction in the context of a bona fide emergency or prospective irreparable
harm, and such an action may be filed and maintained notwithstanding any ongoing
arbitration proceeding.

        8.3    Governing Law.    This Agreement shall be governed by, and
construed and enforced in accordance with, the laws of the State of New York
excluding its conflicts of laws principles.

        8.4    Modification.    This Agreement may only be modified or
supplemented in a writing expressly stated for such purpose and signed by all
the parties to this Agreement. To the extent a party has no interest in any such
modification or supplement, such party shall act in good faith in agreeing to
such modification or supplement.

        8.5    Relationship Among the Parties.    The parties' relationship, as
established by this Agreement, is solely that of independent contractors. This
Agreement does not create any partnership, joint venture or similar business
relationship among the parties. No party is a legal representative of any other
party, and no party can assume or create any obligation, representation,
warranty or guarantee, express or implied, on behalf of any other party for any
purpose whatsoever.

        8.6    Non-Waiver.    The failure of a party to insist upon strict
performance of any provision of this Agreement or to exercise any right arising
out of this Agreement shall neither impair that provision or

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right nor constitute a waiver of that provision or right, in whole or in part,
in that instance or in any other instance. Any waiver by a party of a particular
provision or right shall be in writing, shall be as to a particular matter and,
if applicable, for a particular period of time and shall be signed by such
party.

        8.7    Assignment.    The parties may assign this Agreement under the
same circumstances as permitted for assignment of the License Agreement, the
Trademark Agreement, the Supply Agreement and the Collaboration Agreement.

        8.8    No Third Party Beneficiaries.    This Agreement is neither
expressly nor impliedly made for the benefit of any party other than those
executing it.

        8.9    Severability.    If, for any reason, any part of this Agreement
is adjudicated invalid, unenforceable or illegal by a court of competent
jurisdiction, such adjudication shall not affect or impair, in whole or in part,
the validity, enforceability or legality of any remaining portions of this
Agreement. All remaining portions shall remain in full force and effect as if
the original Agreement had been executed without the invalidated, unenforceable
or illegal part.

        8.10    Notices.    Any notice to be given under this Agreement must be
in writing and delivered as described in the License Agreement if to Cypress or
Pierre Fabre and as described in the Collaboration Agreement if to Forest.

        8.11    Legal Fees.    If any party to this Agreement resorts to any
legal action or arbitration in connection with this Agreement, subject to
Section 8.2(e), the prevailing party shall be entitled to recover reasonable
fees of attorneys and other professionals in addition to all court costs and
arbitrator's fees which that party may incur as a result.

        8.12    Interpretation.    

        (a)    Captions & Headings.    The captions and headings of clauses
contained in this Agreement preceding the text of the articles, sections,
subsections and paragraphs hereof are inserted solely for convenience and ease
of reference only and shall not constitute any part of this Agreement, or have
any effect on its interpretation or construction.

        (b)    Singular & Plural.    All references in this Agreement to the
singular shall include the plural where applicable, and all references to gender
shall include both genders and the neuter.

        (c)    Articles, Sections & Subsections.    Unless otherwise specified,
references in this Agreement to any article shall include all sections,
subsections, and paragraphs in such article; references in this Agreement to any
section shall include all subsections and paragraphs in such sections; and
references in this Agreement to any subsection shall include all paragraphs in
such subsection.

        (d)    Days.    All references to days in this Agreement shall mean
calendar days, unless otherwise specified.

        (e)    Ambiguities.    Ambiguities and uncertainties in this Agreement,
if any, shall not be interpreted against either party, irrespective of which
party may be deemed to have caused the ambiguity or uncertainty to exist.

        (f)    Net Sales.    "Net sales" as used in this Agreement shall be
calculated in the same manner as Net Sales is calculated under the Collaboration
Agreement.

        8.13    Counterparts.    This Agreement may be executed in one or more
counterparts, each of which shall be deemed an original document, and all of
which, together with this writing, shall be deemed one instrument.

        8.14    Letter Agreement Control.    In the event of a conflict between
any terms and conditions of this Agreement, on one hand, and the License
Agreement, Supply Agreement, Trademark Agreement

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and Collaboration Agreement on the other hand, this Agreement shall control with
respect to any and the applicable terms and conditions contained herein.

        8.15    Affirmation.    The parties acknowledge and agree that
Section 2.1(e) of the License Agreement remains in full force and effect, and,
accordingly, nothing contained in this Agreement is intended to limit the rights
and obligations of Cypress and Pierre Fabre under the License Agreement,
Trademark Agreement and the Supply Agreement.

        8.16    Certain Matters Regarding the Collaboration
Agreement.    Cypress and Forest hereby represent and warrant to Pierre Fabre
that a true, accurate and complete copy of the Collaboration Agreement has been
delivered to Pierre Fabre. Cypress and Forest agree to promptly provide to
Pierre Fabre copies of any and all amendments, waivers, default notices and
restatements executed and delivered in connection with the Collaboration
Agreement. In addition, Cypress and Forest agree that the rights and authority
of the Joint Development Committee under the Collaboration Agreement do not
supercede the rights and authority of the Steering Committee under the License
Agreement.

[Remainder of Page Intentionally Left Blank]

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        IN WITNESS WHEREOF, the parties hereto have duly executed this
Agreement.

FOREST LABORATORIES IRELAND LIMITED   CYPRESS BIOSCIENCE, INC.
By:
 
/s/  RAYMOND STAFFORD      

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By:
 
/s/  JAY KRANZLER      

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Name:   Raymond Stafford

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  Name:   Dr. Jay Kranzler

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Title:   Chief Executive Officer

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  Title:   Chief Executive Officer

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PIERRE FABRE MÉDICAMENT
 
 
 
 
By:
 
/s/  JEAN PIERRE COUZINIER      

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  Name:   Jean Pierre Couzinier

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        Title:   Chief Operating Officer

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Exhibit 10.28

LETTER AGREEMENT
RECITALS
AGREEMENT