Exhibit 10.22

ViroPharma Bonus Plan

The ViroPharma Incorporated Bonus Plan applies to each of our employees,
including the members of our management team. Each employee receives a target
bonus, expressed as a percentage of his or her base salary for the year. The
amount of a specific employee’s target bonus varies by the employee’s role in
the Company and his or her applicable pay band, as identified in the table
below:

 

 

Exempt Positions             

Position

   Pay Band(s)    Target     Maximum    

CEO

   18    50 %   62.5 %  

Management Team

   17B    50 %   62.5 %  

Management Team

   17A    40 %   50 %  

Vice President

   16    30 %   37.5 %  

Senior Director

   15B    30 %   37.5 %  

Director

   15A    20 %   25 %  

Associate Director

   14    20 %   25 %  

Assistant Director

   13B    20 %   25 %  

Manager

   13A    15 %   18.75 %  

Senior Professional

   12    15 %   18.75 %  

Senior Professional

   11    12 %   15 %  

Mid-level Professional

   10    12 %   15 %  

Professional

   9    12 %   15 %  

Entry Level

   7-8    10 %   12.5 %

Non-Exempt Positions

         

Senior Non-Exempt

   6    10 %   12.5 %  

Non-Exempt

   5    10 %   12.5 %  

Non-Exempt

   2-4    8 %   10 %  

Non-Exempt

   1    6 %   7.5 %

For employees with less than one year of service, the bonus will be pro-rated
based on the actual base pay earnings during the bonus year. Overtime earnings
are not eligible to be included in bonus calculations.

Awards pursuant to the plan are based upon two factors: Company and Individual.
The Company factor represents the degree to which we achieved our overall
corporate goals in a given year. Each employee also is given an Individual
factor by his or her supervisor to reflect the employee’s performance against
his or her individual goals for the year. Each factor can be assigned a value of
up to 125% for maximum performance. Thus, depending on the performance of the
Company and the individual employee, an employee may receive up to 125% of his
or her target bonus.

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Each of the Company and Individual factors is itself separately weighted for
each employee. The weighting assigned to each factor varies by employee
depending on the role he or she plays with the Company and his or her applicable
pay band. For example, for the members of the company’s management team, the
Company factor is weighted significantly higher than the Individual factor in
order to ensure that the bonus system for the company’s management team is
closely tied to the company’s performance.

The weighting of the factors is as follows:

 

Exempt Positions

   Company Factor     Individual Factor  

Pay Bands 17A, 17B, 18

   70 %   30 %

Pay Bands 15A, 15B, 16

   60 %   40 %

All others

   50 %   50 %

To determine the actual bonus paid, an employee’s target payout percentage is
multiplied by the sum of the Company factor plus the Individual factor as each
is weighted for such employee. The result of that calculation is then multiplied
by the employee’s target bonus.

Whether or not a bonus is actually paid, however, is ultimately at the
discretion of the Compensation Committee of the Board of Directors. Bonuses, if
any, are paid during the first quarter of the year immediately following the
year being measured.