Exhibit 10.28

December 14, 2007

Carol Moore

[Home Address Omitted]

Dear Carol,

Cerus Corporation is pleased to offer you the position of Vice President,
Regulatory Affairs & Quality. This letter embodies the terms of our offer of
employment to you.

As the Vice President, Regulatory Affairs & Quality, your principle role will be
to oversee the Regulatory Affairs Departments in the US, Europe and select
countries. Amongst other things, you will be responsible for the implementation
of global strategies for the earliest possible approvals of phase I through
phase IV applications. In this position you will report to Claes Glassell,
President and Chief Executive Officer. You will work at our location in Concord,
California. Of course, Cerus may change your responsibilities and your work
location from time to time, as it deems necessary.

You will be paid semi-monthly at the rate of $12,083.34 which calculates to an
annual salary of $290,000, (the quoting of an annual salary is for illustrative
purposes only). In addition to your salary, in 2008, you will be eligible to
participant in Cerus’ cash bonus plan. The maximum target bonus percentage for
your position is 25% of base salary, pro-rated to your start date. Finally, you
will be paid a signing bonus of $50,000.00 subject to standard payroll
deductions and withholdings. The bonus will be payable within the first, full
pay period following your start date of full time employment. If you voluntarily
resign from Cerus within 12 months of your hire date, the pro-rated amount of
your sign-on bonus will be due to Cerus upon your exit.

In addition to your salary, you will be eligible for all of Cerus’ standard
employee benefits plans which include employer subsidized medical, dental and
vision premiums, long term disability, life insurance, a 401(k) plan, and, upon
meeting eligibility requirements, participation in Cerus’ Employee Stock
Purchase Plan. The Employee Stock Purchase Plan gives employees an opportunity
to obtain an equity position in Cerus Corporation at a favorable price. You will
also be eligible for 15 days of vacation per year. You should note that Cerus
may modify salaries and benefits from time to time as it deems necessary.

Subject to the approval of the Cerus Board of Directors, you will receive an
option exercisable for 100,000 shares of common stock at an exercise price equal
to the fair market value of such shares at the time of the grant as determined
by the Board. The options shall vest as to one eighth of the shares six months
after the vesting start date and as to one forty-eighth of the shares each month
thereafter.

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Normal working hours are from 8:00 a.m. to 5:00 p.m., Monday through Friday. As
an exempt employee, you will be occasionally asked to work additional hours as
required by your assignments.

As a Cerus employee you will be expected to abide by company rules and
regulations. You will be specifically required to sign an acknowledgment that
you have read and understand the company rules of conduct included in the Cerus
Employee Handbook.

You will be expected to sign and comply with a proprietary information and
nondisclosure agreement that requires, among other provisions, the assignment of
patent rights to any invention made during your employment at Cerus and
nondisclosure of proprietary information.

As an employee you may terminate employment at any time and for any reason
whatsoever with notice to Cerus. We request that, in the event of resignation,
you give the Company at least two weeks notice. Similarly, Cerus may terminate
your employment at any time and for any reason whatsoever, with or without cause
(involuntary termination). Furthermore, this mutual termination of employment
arrangement supersedes all our prior written and oral communication with you and
can only be modified by written agreement signed by you and Cerus.

As required by law, this offer is subject to your submission of an I-9 Form and
satisfactory proof of your right to work in the United States no later than
three days after your employment begins. In addition, this offer of employment
is contingent upon satisfactory completion of the background check that was
previously discussed with you.

If you wish to accept employment at Cerus under the terms set out above, please
sign and date this letter, and return it to me by Thursday, December 20, 2007.
If you accept our offer, your first day of employment will be no later than
Monday, March 3, 2008.

We look forward to your favorable reply and to a productive and exciting work
relationship.

Sincerely,

/s/ Lori L. Roll

Lori L. Roll

Vice President, Administration

 

Approved and Accepted  

/s/ Carol Moore

  Date  

12/21/2007

  Carol Moore