MAP Pharmaceuticals, Inc. Offer Letter to Christopher Y. Chai for Chief Financial Officer Position (September 14, 2006)

EXHIBIT 10.9

September 14, 2006

Christopher Chai

Dear Chris:

We are pleased to extend to you this offer of employment with MAP Pharmaceuticals, Inc. under the following terms and conditions.

Your title will be Chief Financial Officer reporting directly to me. Your starting bi-weekly compensation will be $9230.77, annualized to $240,000.

You will be eligible for MAP’s bonus program, which is currently an MBO based program with target goals set at 25%.

Although the issuance of stock options is in the discretion of the Compensation Committee of MAP’s board of Directors, we anticipate that the Compensation Committee will approve the issuance of an option equal to 1.25% of currently outstanding shares to you in connection with the commencement of your full time employment.

As a MAP employee, you will also be eligible for full company benefits, which include Health, Dental, Life, Vision, Vacation and Holidays

This offer is contingent upon your ability to show satisfactory proof of identity and authorization to work in the United States. Please bring the appropriate verification documents (see enclosed document), on your first day of employment. This offer is also contingent upon the successful completion of our employment background check and drug test. You will be provided with information and instructions on the completion of these items and cannot begin your employment until cleared results have been received.

On your first day of employment, you will be required to execute the company’s Confidentiality and Assignment of Inventions Agreement, providing for protection of the company’s proprietary information and trade secrets. We ask that you make every effort to protect the confidential and proprietary information of your current employer.

Christopher Chai – Page 2

As part of employment at MAP Pharmaceuticals, Inc., you will be required to attend Safety Training. Additional information will be given to you upon joining the organization.

Chris, we look forward to having you join the MAP Pharmaceuticals, Inc. team! We believe you will find that MAP Pharmaceuticals, Inc. provides a unique, rewarding work experience.

Please contact me if you have any questions regarding this offer of employment. You may accept this offer by signing below and returning the signed copy, the second copy is for your records.

Sincerely,

I understand that this letter is not a contract, expressed or implied, guaranteeing employment, or employment for any duration. If you choose to accept this offer, you will be an “at will” employee, and your employment with MAP will be voluntarily entered into and will be for no specified period. As a result, you will be free to resign at any time, for any reason or for no reason, as you deem appropriate. MAP will have a similar right, and may conclude our employment relationship with you at any time, with or without cause. Additionally, we may withdraw this offer at any time, with or without notice to you. The provisions stated in this offer of employment supersede all prior discussions and negotiations, and no other writing published by MAP Pharmaceuticals, Inc. is intended to modify the presumptions of at-will employment status.

This offer will expire on September 20, 2006 and it is expected that you will be available to start work on or around September 29, 2006.