Execution Version SECURITIES PURCHASE AGREEMENT This SECURITIES PURCHASE AGREEMENT (this Agreement ), dated as of

SECURITIES PURCHASE AGREEMENT

This SECURITIES PURCHASE AGREEMENT (this Agreement ), dated as of April 13, 2023, is made by and among

REGULUS THERAPEUTICS INC., a Delaware corporation (the Company ), and the Purchasers listed on Exhibit A hereto, together with their permitted transferees (each, a Purchaser and

collectively, the Purchasers ).

A. The Company and the Purchasers are executing and delivering this Agreement in reliance upon the exemption from securities

registration afforded by Section 4(a)(2) of the Securities Act.

B. The Purchasers desire to purchase and the Company desires

to sell, upon the terms and conditions stated in this Agreement, shares of Common Stock (the Common Shares ) and shares of Class A-5 Convertible Preferred Stock (the

Preferred Shares and, together with the Common Shares, the Shares ), having an aggregate purchase price of up to $15,030,083 as more fully described in this Agreement.

C. The capitalized terms used herein and not otherwise defined have the meanings given them in Article 7.

consideration of the premises and the mutual covenants contained herein and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Company and the Purchasers (severally and not jointly) hereby agree

PURCHASE AND SALE OF SECURITIES

(a) Purchase and Sale of Securities. At the closing of the transaction contemplated by this Agreement (the

Closing ), the Company will sell and issue to each Purchaser, and each Purchaser will, severally and not jointly, purchase from the Company, the number of Common Shares equal to (x) the

dollar amount set forth opposite such Purchaser s name on Exhibit A hereto under the heading Subscription Amount divided by (y) the Market Price, rounded down to the nearest whole share; provided, however,

in the event the number of Common Shares resulting from the foregoing calculation would result in such Purchaser, together with its Attribution Parties, beneficially owning in excess of the Beneficial Ownership Limitation of the outstanding

Common Stock immediately after the Closing, then (i) the number of Common Shares otherwise issuable to such Purchaser at the Closing will be reduced by the number (such number, the Overage Number ) of Common Shares that

would result in such Purchaser beneficially owning, together with its Attribution Parties, no more than the Beneficial Ownership Limitation of the outstanding Common Stock immediately after the Closing, and (ii) the Company will issue to such

Purchaser at the Closing the maximum number of whole Preferred Shares which are convertible (in the aggregate and without regard to any conversion limitations) into a number of Conversion Shares that does not exceed the Overage Number.

(b) Payment. At the Closing, each Purchaser will pay to an account designated by the Company, by wire transfer of immediately available funds,

the amount set forth opposite its name on Exhibit A hereto under the heading Subscription Amount . The Company will (i) instruct the Transfer Agent to credit each Purchaser the number of Common Shares purchased by the

Purchaser pursuant to Section 1.1 hereof (and, upon request, will deliver stock certificates to such Purchaser representing such Common Shares), (ii) if applicable, issue a certificate evidencing the Preferred Shares purchased by such Purchaser

pursuant to Section 1.1 hereof and (iii) on the Closing Date (defined below) deliver written notice from the Company or the Transfer Agent evidencing the issuance to the Purchaser of the Common Shares and Preferred Shares on and as of the

(c) Closing Date. The Closing will take place as soon as reasonably practicable after the date

hereof but no later than April 14, 2023 (the date on which the Closing actually occurs, the Closing Date ) and the Closing will be held remotely via the exchange of documents and signatures, or at such other time and place

as agreed upon by the Company and the Purchasers subscribing for a majority of the Shares to be sold and issued hereunder (the Preferred Shares to be counted on an as-converted-to-common-stock basis), based on the amounts set forth on Exhibit A hereto under the heading Subscription Amount .

REPRESENTATIONS AND WARRANTIES OF THE COMPANY

Except as specifically contemplated by this Agreement, the Company hereby represents and warrants to the Purchasers and the Placement Agents

as of the date of this Agreement that:

2.1 Good Standing of the Company. The Company has been duly incorporated, is validly existing as a

corporation in good standing under the laws of the jurisdiction of its incorporation, has the corporate power and authority to own its property and to conduct its business as described in the reports, schedules, forms, statements and other documents

required to be filed by it with the SEC, pursuant to the reporting requirements of the Exchange Act (all of the foregoing filed prior to the date hereof and all exhibits included therein and financial statements and schedules thereto and documents

(other than exhibits) incorporated by reference therein, the SEC Documents ) and is duly qualified to transact business and is in good standing in each jurisdiction in which the conduct of its

business or its ownership or leasing of property requires such qualification, except to the extent that the failure to be so qualified or be in good standing would not have a Material Adverse Effect on the Company.

2.2 Authorization of Capital Stock. The authorized capital stock of the Company consists of 300,000,000 shares of Common Stock, $0.001 par value

per share, and 10,000,000 shares of Preferred Stock, $0.001 par value per share. As of March 31, 2023, 256,700 shares of Preferred Stock were designated Class A-1 Convertible Preferred Stock,

1,330,832 shares were designated Class A-2 Convertible Preferred Stock, 258,707 shares were designated Class A-3 Convertible Preferred Stock and 3,725,720

shares were designated Class A-4 Convertible Preferred Stock. As of the Closing, 140,827 shares of Preferred Stock will be designated Class A-5 Convertible

Preferred Stock. As of March 31, 2023, 16,859,733 shares of Common Stock were issued and outstanding and 5,571,959 shares of Preferred Stock were issued and outstanding, 256,700 shares of which were

Class A-1 Convertible Preferred Stock, 1,330,832 shares of which were Class A-2 Convertible Preferred Stock, 258,707 shares of which were Class A-3 Convertible Preferred Stock and 3,725,720 shares of which were Class A-4 Convertible Preferred Stock. No shares of

Class A-5 Convertible Preferred Stock are issued and outstanding immediately prior to the Closing. The shares of capital stock of the Company, including the Common Stock outstanding prior to the issuance

of the Shares, have been duly authorized and are validly issued, fully paid and non-assessable and were not issued in violation of the preemptive or similar rights of any security holder of the Company.

2.3 Authorization of Shares. The Shares of Common Stock issuable upon conversion of the Class A-5

Convertible Preferred Stock (the Conversion Shares ) have been duly authorized and, when issued and delivered in accordance with the terms of this Agreement and the

Class A-5 Certificate of Designation, will be validly issued, fully paid and non-assessable, and the issuance of such Shares and Conversion Shares will not be

subject to any preemptive or similar rights of stockholders of the Company.

2.4 Private Placement. Neither the Company nor any of its Affiliates, nor any Person acting on

its or their behalf, has, directly or indirectly, made any offers or sales of any security or solicited any offers to buy any security, under any circumstances that would require registration of the Shares under the Securities Act. Assuming the

accuracy of the representations and warranties of the Purchasers contained in Article 3 hereof, the issuance of the Shares and the Conversion Shares are exempt from registration under the Securities Act.

2.5 Authorization and Execution of Agreement. This Agreement has been duly authorized, executed and delivered by the Company. The Company has

all requisite corporate power and authority to execute, deliver and perform its obligations under this Agreement.

2.6 Absence of Defaults and

Conflicts. Except as otherwise disclosed in the SEC Documents, the Company is not (i) in violation of its charter, by-laws or similar incorporation or organizational documents or (ii) in

violation or default in the performance or observance of any obligation, agreement, covenant or condition contained in any contract, indenture, mortgage, deed of trust, loan or credit agreement, note, lease or other agreement or instrument to which

the Company is a party or by which it may be bound, or to which any of the property or assets of the Company is subject (collectively, Agreements and Instruments ), except in the case of clause

(ii), for such violations and defaults that would not result in a Material Adverse Effect on the Company; and the execution, delivery and performance of this Agreement and the consummation of the transactions contemplated in this Agreement, and

compliance by the Company with its obligations under this Agreement, do not and will not, whether with or without the giving of notice or passage of time or both, conflict with or result in a breach of any of the terms and provisions of, or

constitute a default or Repayment Event (as defined below) under, or result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of the Company pursuant to, the Agreements and Instruments, nor will such action

result in any violation of the provisions of the charter, by-laws or similar organizational documents of the Company or any applicable law, statute, rule, regulation, judgment, order, writ or decree of any

government, government instrumentality or court, domestic or foreign, having jurisdiction over the Company or any of its assets, properties or operations, except in each case (other than with respect to such charter,

by-laws or similar organizational documents of the Company) for such conflicts, violations, breaches or defaults which would not reasonably be expected to result in a Material Adverse Effect on the Company. As

used herein, a Repayment Event means any event or condition which gives the holder of any note, debenture or other evidence of indebtedness that is material to the operations or

financial results of the Company (or any person acting on such holder s behalf) the right to require the repurchase, redemption or repayment of all or a portion of such indebtedness by the Company.

2.7 Absence of Further Requirements. No filing with, or authorization, approval, consent, license, order, registration, exemption, qualification

or decree of, any court or governmental authority or agency or any sub- division thereof is required for the performance by the Company of its obligations hereunder, in connection with the offering, issuance

or sale of the Shares and Conversion Shares under this Agreement or the consummation of the transactions contemplated by this Agreement, except such as have been already obtained or as may be required under the Securities Act or the rules and

regulations of the SEC thereunder, state securities or blue sky laws, the rules and regulations of the Financial Industry Regulatory Authority, Inc. ( FINRA ) or Nasdaq.

2.8 No Material Adverse Effect. Except as otherwise disclosed in the SEC Documents, subsequent to the respective dates as of which information

is given in the SEC Documents: (a) the Company has not sustained any material loss or material interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court

or governmental action, order or decree, (b) there has not been any change in the capital stock or increase in short-term or long-term debt of the Company, other than a change in the number of outstanding shares of Common Stock due to the

issuance of shares upon the exercise or settlement of outstanding options, warrants or restricted stock units as described in the SEC Documents, and (c) there has not occurred any Material Adverse Effect, or any development that would result in

a prospective Material Adverse Effect, in or affecting the condition, financial or otherwise, or in or affecting the revenues, business, assets, management, financial position, stockholders equity, operations or results of operations or

prospects of the Company.

2.9 Absence of Proceedings. There are no legal or governmental proceedings, inquiries or

investigations pending or, to the Company s knowledge, threatened to which the Company is a party or to which any of the properties of the Company is subject, other than proceedings accurately described in all material respects in the SEC

Documents or proceedings that would not have a Material Adverse Effect on the Company, or on the power or ability of the Company to perform its obligations under this Agreement or to consummate the transactions contemplated by this Agreement.

2.10 Investment Company Act of 1940. The Company is not, and after giving effect to the offering and sale of the Shares and the application of

the proceeds thereof as described herein will not be, required to register as an investment company as such term is defined in the Investment Company Act of 1940, as amended.

2.11 Registration Rights. Except as described in the SEC Documents, there are no contracts, agreements or understandings between the Company and

any person granting such person the right to require the Company to file a registration statement under the Securities Act with respect to any securities of the Company or to require the Company to include such securities with the Shares and

Conversion Shares registered pursuant to a Registration Statement other than rights that have been validly waived.

2.12 Title to Real and

Personal Property. Except as set forth in the SEC Documents, the Company has good and marketable title in fee simple to all real property and good and marketable title to all personal property owned by it which is material to the business of the

Company, in each case free and clear of all liens, encumbrances and defects, except such as are described in the SEC Documents or such as do not materially affect the value of such property and do not materially interfere with the use made and

proposed to be made of such property by the Company; and any real property and buildings held under lease by the Company are held by it under valid, subsisting and enforceable leases with such exceptions as are not material and do not interfere with

the use made and proposed to be made of such property and buildings by the Company.

2.13 Title to Intellectual Property. Except as

disclosed in the SEC Documents, the Company owns, possesses, licenses or has other rights to use all patents, patent applications, trade and service marks, trade and service mark registrations, trade names, copyrights, licenses, inventions, trade

secrets, technology, know-how and other intellectual property that, to the knowledge of the Company, is necessary for the conduct of the Company s business as now conducted (as described in the SEC

Documents, collectively, the Company Intellectual Property ), and, to the Company s knowledge, the patents, trademarks, and copyrights included within the Company Intellectual Property are

valid, enforceable, and subsisting. Except as set forth in the SEC Documents or except in each case as would not reasonably be expected to have a Material Adverse Effect on the Company: (a) there are no material rights of third parties to any

such Company Intellectual Property; (b) to the Company s knowledge, there is no material infringement by third parties of any such Company Intellectual Property; (c) there is no pending or, to the Company s knowledge, threatened

action, suit, proceeding or claim by others challenging the Company s rights in or to any such Company Intellectual Property; (d) there is no pending or, to the Company s knowledge, threatened action, suit, proceeding or claim by

others challenging the validity or scope of any such Company Intellectual Property; (e) there is no pending or, to the Company s knowledge, threatened action, suit, proceeding or claim by others that the Company infringes or otherwise

violates any patent, trademark, copyright, trade secret or other proprietary rights of others; (f) to the Company s knowledge, there is no U.S. patent which contains claims that dominate any Company Intellectual Property described in the

SEC Documents or that interferes under 35 U.S.C. 102(g) with the pending claims of any Company Intellectual Property; (g) to the Company s knowledge, there is no prior art of which the Company is aware that would render any U.S.

patent held by the Company invalid which has not been disclosed to the U.S. Patent and Trademark Office (the PTO ); and (h) the Company is not obligated to pay a material royalty, grant a

license, or provide other material

consideration to any third party in connection with the Company Intellectual Property. Except as otherwise

disclosed in the SEC Documents, to the Company s knowledge, all patents and patent applications owned by the Company and filed with the PTO or any foreign or international patent authority (the Company Patent Rights )