Exhibit 10.28

[COTHERIX LETTERHEAD]

December 7, 2003

Klara A. Dickinson

3067 Terrace Drive

Aptos, CA 95003

Dear Klara:

CoTherix, Inc. (the “Company”) is pleased to offer you employment on the
following terms:

1. Position. Your initial title will be Director, Regulatory Affairs, and you
will initially report to the Company’s President & COO. This is a full-time
position. By signing this letter agreement, you confirm to the Company that you
have no contractual commitments or other legal obligations that would prohibit
you from performing your duties for the Company.

2. Cash Compensation. The Company will pay you a starting salary at the rate of
$140,000 per year, payable in accordance with the Company’s standard payroll
schedule. This salary will be subject to adjustment pursuant to the Company’s
employee compensation policies in effect from time to time. In addition, you
will be eligible to receive the following bonuses:

 

  •   a sign-on bonus of $5,000 payable within 30 days of your start date

 

  •   a $25,000 bonus for completing filing of the Ventavis® NDA. This bonus is
payable within 30 days of the NDA filing acceptable date.

Termination with cause or your resignation within the first 12 months of your
employment requires that you re-pay the sign-on bonus within 30 days of your
date of your termination. The determinations of the Company’s Board of Directors
with respect to your bonus will be final and binding.

3. Employee Benefits. As a regular employee of the Company, you will be eligible
to participate in a number of Company-sponsored benefits. In addition, you will
be entitled to paid vacation in accordance with the Company’s vacation policy,
as in effect from time to time.

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Klara Dickinson

December 7, 2003

Page 2

4. Stock Options. Subject to the approval of the Company’s Board of Directors or
it Compensation Committee, you will be granted an option to purchase 73,505
shares of the Company’s Common Stock (share number reflects reverse split). The
exercise price per share will be equal to the fair market value per share on the
date the option is granted or on your first day of employment, whichever is
later. The option will be subject to the terms and conditions applicable to
options granted under the Company’s 2000 Stock Plan (the “Plan”), as described
in the Plan and the applicable Stock Option Agreement. The option will be
immediately exercisable, but the unvested portion of the purchased shares will
be subject to repurchase by the Company at the exercise price in the event that
your service terminates for any reason before you vest in the shares. You will
vest in 25% of the option shares after 12 months of continuous service, and the
balance will vest in equal monthly installments over the next 36 months of
continuous service, as described in the applicable Stock Option Agreement.

5. Proprietary Information and Inventions Agreement. Like all Company employees,
you will be required, as a condition of your employment with the Company, to
sign the Company’s standard Proprietary Information and Inventions Agreement, a
copy of which is attached hereto as Exhibit A.

6. Employment Relationship. Employment with the Company is for no specific
period of time. Your employment with the Company will be “at will,” meaning that
either you or the Company may terminate your employment at any time and for any
reason, with or without cause. Any contrary representations that may have been
made to you are superseded by this letter agreement. This is the full and
complete agreement between you and the Company on this term. Although your job
duties, title, compensation and benefits, as well as the Company’s personnel
policies and procedures, may change from time to time, the “at will” nature of
your employment may only be changed in an express written agreement signed by
you and a duly authorized officer of the Company (other than you).

7. Outside Activities. While you render services to the Company, you agree that
you will not engage in any other employment, consulting or other business
activity without the prior written consent of the Company. While you render
services to the Company, you also will not assist any person or entity in
competing with the Company, in preparing to compete with the Company or in
hiring any employees or consultants of the Company.

8. Withholding Taxes. All forms of compensation referred to in this letter
agreement are subject to reduction to reflect applicable withholding and payroll
taxes and other deductions required by law.

9. Entire Agreement. This letter agreement supersedes and replaces any prior
agreements, representations or understandings, whether written, oral or implied,
between you and the Company.

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Klara Dickinson

December 7, 2003

Page 3

10. Arbitration. You and the Company agree to waive any rights to a trial before
a judge or jury and agree to arbitrate before a neutral arbitrator any and all
claims or disputes arising out of this letter agreement and any and all claims
arising from or relating to your employment with the Company, including (but not
limited to) claims against any current or former employee, director or agent of
the Company, claims of wrongful termination, retaliation, discrimination,
harassment, breach of contract, breach of the covenant of good faith and fair
dealing, defamation, invasion of privacy, fraud, misrepresentation, constructive
discharge or failure to provide a leave of absence, or claims regarding
commissions, stock options or bonuses, infliction of emotional distress or
unfair business practices.

The arbitrator’s decision must be written and must include the findings of fact
and law that support the decision. The arbitrator’s decision will be final and
binding on both parties, except to the extent applicable law allows for judicial
review of arbitration awards. The arbitrator may award any remedies that would
otherwise be available to the parties if they were to bring the dispute in
court. The arbitration will be conducted in accordance with the National Rules
for the Resolution of Employment Disputes of the American Arbitration
Association; provided, however that the arbitrator must allow the discovery
authorized by the California Arbitration Act or the discovery that the
arbitrator deems necessary for the parties to vindicate their respective claims
or defenses. The arbitration will take place in San Mateo County or, at your
option, the county in which you primarily worked with the Company at the time
when the arbitrable dispute or claim first arose.

You and the Company will share the costs of arbitration equally, except that the
Company will bear the cost of the arbitrator’s fee and any other type of expense
or cost that you would not be required to bear if you were to bring the dispute
or claim in court. Both the Company and you will be responsible for their own
attorneys’ fees, and the arbitrator may not award attorneys’ fees unless a
statute or contract at issue specifically authorizes such an award.

The foregoing notwithstanding, this arbitration provision does not apply to
(a) workers’ compensation or unemployment insurance claims or (b) claims
concerning the ownership, validity, infringement, misappropriation, disclosure,
misuse or enforceability of any confidential information, patent right,
copyright, mask work, trademark or any other trade secret or intellectual
property held or sought by either you or the Company (whether or not arising
under the Proprietary Information and Inventions Agreement between you and the
Company).

If an arbitrator or court of competent jurisdiction (the “Neutral”) determines
that any provision of this arbitration provision is illegal or unenforceable,
then the Neutral shall modify or replace the language of this arbitration
provision with a valid and enforceable provision, but only to the minimum extent
necessary to render this arbitration provision legal and enforceable.

******

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Klara Dickinson

December 7, 2003

Page 4

We hope that you will accept our offer to join the Company. You may indicate
your agreement with these terms and accept this offer by signing and dating both
the enclosed duplicate original of this letter agreement and the enclosed
Proprietary Information and Inventions Agreement and returning them to me. This
offer, if not accepted, will expire at the close of business on December 15,
2003. As required by law, your employment with the Company is contingent upon
your providing legal proof of your identity and authorization to work in the
United States. Your employment is also contingent upon your starting work with
the Company on or before January 5, 2004.

If you have any questions, please call me at 650-486-2102.

 

Very truly yours, COTHERIX, INC. By:  

/s/ Donald J. Santel

  Donald J. Santel Title:   President & COO

I have read and accept this employment offer:

 

/s/ Klara Dickinson

Signature of Klara Dickinson Dated:   12/10/03

Attachment

Exhibit A: Proprietary Information and Inventions Agreement