Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): September 06, 2023



Ultragenyx Pharmaceutical Inc.

(Exact name of Registrant as Specified in Its Charter)






(State or Other Jurisdiction
of Incorporation)

(Commission File Number)

(IRS Employer
Identification No.)






60 Leveroni Court


Novato, California



(Address of Principal Executive Offices)


(Zip Code)


Registrant’s Telephone Number, Including Area Code: 415 483-8800



(Former Name or Former Address, if Changed Since Last Report)


Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class




Name of each exchange on which registered

Common Stock, $0.001 par value




Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.



Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

As reported by Ultragenyx Pharmaceutical Inc. (the “Company”) in its Current Report on Form 8-K filed with the Securities and Exchange Commission (the “SEC”) on July 12, 2023 (the “Form 8-K”), the Company previously announced that Howard Horn has been appointed as the Company’s Chief Financial Officer and Executive Vice President, Corporate Strategy (“CFO and EVP, Corporate Strategy”), effective as of October 16, 2023. Mr. Horn and the Company have modified the effective date of Mr. Horn’s appointment as the Company’s CFO and EVP, Corporate Strategy from October 16, 2023 to October 9, 2023 (the “Effective Date”).

In connection with the modification to the Effective Date as described above, the Company and Mr. Horn entered into Amendment No. 1 dated September 6, 2023 (the “Offer Letter Amendment”), to the offer letter dated June 22, 2023 (the “Offer Letter”). The foregoing description of the Offer Letter Amendment is only a summary and is qualified in its entirety by reference to the full text of the Offer Letter Amendment, a copy of which is filed as Exhibit 10.1, and incorporated by reference herein.

A copy of the Offer Letter was previously filed with the SEC as Exhibit 10.1 on the Form 8-K.

Item 9.01 Financial Statements and Exhibits.


Exhibit No.



Amendment dated September 6, 2023 to the Offer Letter between Howard Horn and Ultragenyx Pharmaceutical Inc. dated June 22, 2023.


The cover page from the Company’s Current Report on Form 8-K dated September 6, 2023 formatted in Inline XBRL.




Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.




Ultragenyx Pharmaceutical Inc.






September 8, 2023


/s/ Emil D. Kakkis




Emil D. Kakkis, M.D., Ph.D.
President and Chief Executive Officer



Exhibit 10.1


Going beyond every day.™



September 6, 2023


Howard Horn


Re: Amendment No. 1 to Offer Letter


Dear Howard:


On behalf of Ultragenyx Pharmaceutical Inc. (“Ultragenyx” or the “Company”), I am pleased to present to you this Amendment No. 1 (this “Amendment”), which amends the Offer of Employment Letter Agreement with you dated June 22, 2023 (the “Offer Letter”) as follows:


The first introductory paragraph in the Offer Letter is hereby amended by replacing the reference to “October 16, 2023” with the term “October 9, 2023”.


Except as expressly amended herein, all terms and provisions of the Offer Letter shall remain in full force and effect.


In the event of a conflict between the provisions of this Amendment and the provisions of the Offer Letter, the provisions of this Amendment shall control.


This Amendment may be executed in one or more counterparts, each of which will be deemed to be an original as against any party that has signed it, but all of which together will constitute one and the same instrument.



Warm Regards,


/s/ Emil D. Kakkis


Emil D. Kakkis, M.D., Ph.D.

Chief Executive Officer



I accept and agree the terms and conditions of this Amendment:



Signature: /s/ Howard Horn Dated: September 6, 2023