Exhibit 99.1

Report of Independent Registered Public Accounting Firm

Board of Directors and Shareholders of

Regulus Therapeutics Inc.

We have audited the balance sheets of Regulus Therapeutics Inc. (formerly Regulus Therapeutics LLC)(an equity investment of Alnylam Pharmaceuticals, Inc.) as of December 31, 2011 and 2010, and the related statements of operations, stockholders’(members’) equity, and cash flows for each of the three years in the period ended December 31, 2011 (not presented separately herein). These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on these financial statements based on our audits.

We conducted our audit in accordance with generally accepted auditing standards as established by the Auditing Standards Board (United States) and in accordance with the auditing standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. Our audit included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting. Accordingly we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audit provides a reasonable basis for our opinion.

In our opinion, the financial statements referred to above present fairly, in all material respects, the financial position of Regulus Therapeutics Inc. (formerly Regulus Therapeutics LLC) at December 31, 2011 and 2010, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2011, in conformity with U.S. generally accepted accounting principles.

/s/ Ernst & Young LLP

San Diego, California

February 9, 2012