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

Date of Report (Date of earliest event reported): August 11, 2023

Histogen Inc.

(Exact name of registrant as specified in its charter)






(State or other jurisdiction of

incorporation or organization)


File Number)

(IRS Employer

Identification No.)




10655 Sorrento Valley Road, Suite 200,

San Diego CA



(Address of principal executive offices)


(Zip Code)


(858) 526-3100

(Registrant’s telephone number, including area code)



(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, $0.0001 par value


The Nasdaq Capital 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 4.01 Changes in Registrant's Certifying Accountant.


On August 11, 2023, Histogen Inc. (the “Company”) was informed by Mayer Hoffman McCann P.C. (“MHM”), the Company’s current independent registered public accountant, that MHM would not stand for re-appointment for the fiscal year ending December 31, 2024. MHM will cease to serve as the Company’s independent registered public accountant upon the earliest of (i) the completion of MHM’s procedures on the audited financial statements of the Company and the filing of the Form 10-K as of and for the year ended December 31, 2023, (ii) the appointment of a new independent registered public accounting firm, or (iii) April 1, 2024.


MHM’s audit reports on the Company's financial statements as of and for the years ended December 31, 2021 and 2022 did not contain an adverse opinion or a disclaimer of opinion, and were not qualified or modified as to uncertainty, audit scope or accounting principles, except the audit report for the fiscal year ended December 31, 2022, which contained a “going concern” explanatory paragraph.


During the years ended December 31, 2021 and 2022, and during the subsequent interim period through August 3, 2023, there were no (a) disagreements with MHM on any matter of accounting principles or practices, financial statement disclosure, or auditing scope or procedure, which disagreements, if not resolved to MHM's satisfaction, would have caused MHM to make reference to the subject matter thereof in connection with its reports for such periods; or (b) reportable events, as described under Item 304(a)(1) (v) of Regulation S-K.


In accordance with Item 304(a)(3) of Regulation S-K, the Company provided MHM with a copy of the disclosures it is making in this Current Report on Form 8-K and requested from MHM a letter addressed to the Securities and Exchange Commission indicating whether it agrees with such disclosures. A copy of MHM’s letter dated August 15, 2023, is attached as Exhibit 16.1 hereto.


Item 9.01 Financial Statements and Exhibits


(d) Exhibits


Exhibit Number





Letter of Mayer Hoffman McCann P.C. to the Securities and Exchange Commission, dated August 15, 2023.



Cover Page Interactive Data File (embedded within the Inline XBRL document)



* * *




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.





Histogen Inc.

Date: August 15, 2023


/s/ Susan A. Knudson

Name: Susan A. Knudson

Title: Executive Vice President, Chief Operations Officer and Chief Financial Officer








Exhibit 16.1




August 15, 2023

Securities and Exchange Commission
100 F Street N.E.
Washington, D.C. 20549


We have read Item 4.01 of Histogen Inc.’s Form 8-K dated August 15, 2023, and we agree with the statements set forth in Item 4.01, insofar as they relate to our firm. We have no basis to agree or disagree with other statements made by the registrant contained in Item 4.01.

Very truly yours,

/s/ Mayer Hoffman McCann P.C.

San Diego, California