UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K/A

(Amendment No. 1)

(Mark One)

For the fiscal year ended December 31, 2021

OR

FOR THE TRANSITION PERIOD FROM                      TO                     

Commission File Number 001-39303

PLIANT THERAPEUTICS, INC.

(Exact name of Registrant as specified in its Charter)

Registrant’s telephone number, including area code: (650) 481-6770

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

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    YES  ☐    NO  ☒

Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act.    YES  ☐    NO  ☒

Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    YES  ☒    NO  ☐

Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files).    YES  ☒    NO  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

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.  ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.  ☒

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    YES  ☐    NO  ☒

The aggregate market value of the voting and non-voting common equity held by non-affiliates of the Registrant, based on the closing price of the shares of common stock on The NASDAQ Stock Market on June 30, 2021, was $751,814,002.

The number of shares of Registrant’s Common Stock outstanding as of February 25, 2022 was 36,113,521.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s definitive Proxy Statement for the 2022 Annual Meeting of Stockholders to be filed with the U.S. Securities and Exchange Commission pursuant to Regulation 14A not later than 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K are incorporated by reference in Part III, Items 10-14 of this Annual Report on Form 10-K

EXPLANATORY NOTE

Pliant Therapeutics, Inc. (the “Company”) is filing this Amendment No. 1 (this “Amendment”) to its Annual Report on Form 10-K for the year ended December 31, 2021, originally filed with the Securities and Exchange Commission on March 1, 2022 (the “Original Filing”), to file Exhibit 23.1, Consent of Deloitte & Touche LLP (“Deloitte”), Independent Registered Public Accounting Firm, to the incorporation by reference of Deloitte’s report dated February 28, 2022 relating to the financial statements of Pliant Therapeutics, Inc. and the effectiveness of Pliant Therapeutics, Inc.’s internal control over financial reporting into the Company’s Registration Statement Nos. 333-238922 and 333-254361 on Form S-8 and Registration Statement No. 333-257684 on Form S-3 (the “Auditor Consent”). The Original Filing inadvertently omitted the Auditor Consent. This Amendment is being filed solely to provide the Auditor Consent.

Except as described in this Explanatory Note, this Amendment does not modify, amend, or update in any way the financial information or any other information set forth in the Original Filing.

Item 15. Exhibits

Item 15 of the Original Filing is hereby amended solely to update the Exhibit Index to include the Consent of Deloitte & Touche LLP (23.1) with the new certifications required pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. The updated Exhibit Index is below.

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this Amendment No. 1 to the Annual Report on Form 10-K for the year ended December 31, 2021 to be signed on its behalf by the undersigned, thereunto duly authorized.

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement No.’s 333-238922 and 333-254361 on Form S-8, and Registration Statement No. 333-257684 on Form S-3 of our report dated February 28, 2022 relating to the financial statements of Pliant Therapeutics, Inc. and the effectiveness of Pliant Therapeutics, Inc.’s internal control over financial reporting, appearing in the Annual Report on Form 10-K of Pliant Therapeutics, Inc. for the year ended December 31, 2021.

San Francisco, California

February 28, 2022

Exhibit 31.3

CERTIFICATION PURSUANT TO RULE 13a-14(a) OR 15d-14(a) OF

THE SECURITIES EXCHANGE ACT OF 1934,

AS ADOPTED PURSUANT TO SECTION 302 OF

THE SARBANES-OXLEY ACT OF 2002

I, Bernard Coulie, certify that:

Exhibit 31.4

CERTIFICATION PURSUANT TO RULE 13a-14(a) OR 15d-14(a) OF

THE SECURITIES EXCHANGE ACT OF 1934,

AS ADOPTED PURSUANT TO SECTION 302 OF

THE SARBANES-OXLEY ACT OF 2002

I, Keith Cummings, certify that: