December 3, 2020
5320 Legacy Drive
Plano, Texas 75024
Ladies and Gentlemen:
We have acted as
counsel to Reata Pharmaceuticals, Inc., a Delaware corporation (the Company), with respect to certain legal matters in connection with the offer and sale (the Offering) by the Company of 2,000,000 shares
(the Firm Securities) of the Companys Class A common stock, par value $0.001 per share (the Class A Common Stock), and up to an additional 300,000 shares (the Option Securities, and
together with the Firm Securities, the Securities) of Class A Common Stock, each of which are being sold pursuant to the Underwriting Agreement dated as of December 1, 2020 (the Underwriting
Agreement), between the Company and Barclays Capital Inc. and Goldman Sachs & Co. LLC (the Underwriters); the Securities have been offered for sale pursuant to a prospectus supplement dated December 1, 2020
(the Prospectus Supplement), filed with the Securities and Exchange Commission (the Commission) pursuant to Rule 424(b) on December 3, 2020, to a prospectus dated July 23, 2018 (as amended and
supplemented by the Prospectus Supplement, the Prospectus) that constitutes a part of the Companys automatically effective Registration Statement on Form S-3 (Registration No. 333-226289), filed with the Commission on July 23, 2018 (the Registration Statement).
We have examined (i) the Underwriting Agreement; (ii) the Registration Statement; (iii) the Prospectus Supplement;
(iv) the Prospectus; (v) the Thirteenth Amended and Restated Certificate of Incorporation of the Company and the Second Amended and Restated Bylaws of the Company; (vi) resolutions adopted by the Board of Directors of the Company
relating to the Registration Statement, the Offering and related matters; (vii) resolutions adopted by the Pricing Committee of the Board of Directors of the Company relating to the Offering; and (viii) such other certificates, statutes
and other instruments and documents as we considered appropriate for purposes of the opinions hereafter expressed. In addition, we reviewed such questions of law as we considered appropriate.
As to any facts material to the opinions contained herein, we have made no independent investigation of such facts and have relied, to the
extent that we deem such reliance proper, upon certificates of public officials and officers or other representatives of the Company.
connection with rendering the opinion set forth below, we have assumed that (i) all information contained in all documents reviewed by us is true and correct; (ii) all signatures on all documents examined by us are genuine; (iii) all
documents submitted to us as originals are authentic and complete; (iv) all documents submitted to us as copies conform to the originals of those documents; (v) all persons executing and delivering the documents we examined were competent
to execute and deliver such documents; (vi) all Securities will be issued and sold in compliance with applicable federal and state securities laws and in the manner stated in the Registration Statement and Prospectus; and (vii) the
Underwriting Agreement has been duly authorized and validly executed and delivered by the Underwriters and constitutes a legal, valid and binding obligation of the Underwriters, and the Underwriters have the requisite organizational and legal power
and authority to perform their obligations under the Underwriting Agreement.
Based on the foregoing, and subject to the assumptions,
qualifications, limitations and exceptions set forth herein, we are of the opinion that the Securities to be issued and sold by the Company to the Underwriters as contemplated by the Underwriting Agreement have been duly authorized and, upon payment
and delivery in accordance with the Underwriting Agreement, will be validly issued, fully paid and non-assessable.
Vinson & Elkins LLP Attorneys at Law
Austin Dallas Dubai Houston London New York
Richmond Riyadh San
Francisco Tokyo Washington
Trammell Crow Center, 2001 Ross Avenue, Suite 3900
Dallas, TX 75201-2975
Tel +22.214.171.12400 Fax