Regulus Reports Second Quarter 2015 Financial Results and Recent Highlights -Advanced Clinical Map Initiative with Start of Key Clinical Trials for RG-101 and RG-012- -Maintained Strong Financial Position Ending Q2 2015

Regulus Reports Second Quarter 2015 Financial Results and Recent Highlights

-Advanced Clinical Map Initiative with Start of Key Clinical Trials for RG-101 and RG-012-

-Maintained Strong Financial Position Ending Q2 2015 with $139.4 Million in

LA JOLLA, Calif., August 4, 2015

Regulus Therapeutics Inc. (NASDAQ:RGLS), a biopharmaceutical company leading the discovery and development of innovative medicines targeting microRNAs, today reported financial results and highlights for the quarter ended June 30,

2015 and provided a summary of recent corporate highlights.

The second quarter of 2015 and recent period marked an important time of progression

for Regulus, said Paul Grint, M.D., President and CEO of Regulus. Our pivotal achievements reflect the rapid advancement of our microRNA therapeutics portfolio, most notably with the start of our Phase II study of RG-101 announced today,

and our Phase I study of RG-012 in healthy volunteers. Looking ahead, Regulus is poised for a data rich period with read outs expected on RG-101, RG-012 and RG-125 in the second half of the year.

We believe that our strong cash position, coupled with continued funding from our strategic alliance partners and collaborators, will support the growth

of our company focused on microRNAs, said David Szekeres, Chief Business Officer and General Counsel of Regulus. As we continue to execute on our goals, we expect to meet our guidance of ending 2015 with greater than $100.0 million in

cash, cash equivalents and short-term investments.

Second Quarter 2015 and Recent Highlights

Second Quarter 2015 Financial Results & Highlights

Regulus reported a net loss of $21.0 million and $35.5 million for the three and six months ended June 30, 2015, compared to a net loss of $12.0 million

and $24.7 million for the same periods in 2014. Basic and diluted net loss per share was $0.41 for the three months ended June 30, 2015, compared to basic and diluted net loss per share of $0.28 and $0.29, respectively, for the same period in

2014. Basic and diluted net loss per share was $0.70 for the six months ended June 30, 2015, compared to $0.57 for the same period in 2014.

recognized revenue of $3.8 million and $8.0 million for the three and six months ended June 30, 2015, respectively, compared to $0.7 million and $2.4 million for the same periods in 2014. Revenue included $2.6 million and $3.2 million for

research services under Regulus strategic alliances and collaborations for the three and six months ended June 30, 2015, respectively. Revenue for the six months ended June 30, 2015 included a $2.5 million pre-clinical milestone upon

AstraZeneca s selection of RG-125(AZD4076) as a clinical candidate and $0.4 million of other research milestones under Regulus collaboration and license agreement with Biogen. Other revenue during these periods consisted primarily of

amortization of up-front payments received from Regulus strategic alliances and collaborations, which is recognized over the estimated period of performance.

Research and development expenses were $19.2 million and $32.6 million for the three and six months ended

June 30, 2015, respectively, compared to $10.8 million and $20.4 million for the same periods in 2014. This increase was primarily driven by clinical trial costs for RG-101, pre-clinical study costs for RG-125 and an increase in salaries and

related employee costs, including non-cash stock-based compensation and a non-recurring severance charge associated with the resignation of Regulus former chief scientific officer.

General and administrative expenses were $5.8 million and $9.5 million for the three and six months ended June 30, 2015, respectively, compared to $3.0

million and $5.7 million for the same periods in 2014. This increase was primarily driven by an increase in salaries and related employee costs, including non-cash stock-based compensation and a non-recurring severance charge associated with the

resignation of Regulus former chief executive officer.

Net loss for the six months ended June 30, 2015 and 2014 included non-cash charges

recorded from changes in the value of a convertible note payable of $1.8 million and $1.2 million, respectively. Changes in value were primarily driven by changes in Regulus stock price during the respective periods.

As of June 30, 2105, Regulus had $139.4 million in cash, cash equivalents and short-term investments and 51,533,416 shares of common stock outstanding.

2015 Financial Guidance

Regulus cash guidance

remains unchanged and the company expects to end 2015 with greater than $100.0 million in cash, cash equivalents and short-term investments.

Conference Call & Webcast Information

will host a conference call and webcast at 5:00 p.m. Eastern Daylight Time today to discuss its second quarter 2015 financial results, recent company highlights and its expectations for the remainder of 2015. A live webcast of the call will be

available online at www.regulusrx.com. To access the call, please dial (877) 257-8599 (domestic) or (970) 315-0459 (international) and refer to conference ID 94645440. To access the telephone replay of the call, dial

(855) 859-2056 (domestic) or (404) 537-3406 (international), passcode 94645440. The webcast and telephone replay will be archived on the company s website following the call.

Regulus Therapeutics Inc.

(NASDAQ:RGLS) is a biopharmaceutical company leading the discovery and development of innovative medicines targeting microRNAs. Regulus has leveraged its oligonucleotide drug discovery and development expertise to develop a well-balanced

microRNA therapeutics pipeline complemented by a maturing microMarkersSM biomarkers platform and a rich intellectual property estate to retain its leadership in the microRNA field. Under its

Clinical Map Initiative , Regulus is developing RG-101, a GalNAc-conjugated anti-miR targeting microRNA-122 for the treatment of chronic hepatitis C virus infection, and RG-012, an anti-miR targeting microRNA-21 for the treatment of

Alport syndrome, a life-threatening kidney disease driven by genetic mutations with no approved therapy. In addition, RG-125, a GalNAc-conjugated anti-miR targeting microRNA-103/107 for the treatment of NASH in patients with type 2

diabetes/pre-diabetes, has been selected for clinical development. Regulus is also advancing several programs toward clinical development in orphan disease indications, oncology and fibrosis. Regulus commitment to innovation has resulted in

multiple peer-reviewed publications in notable scientific journals and has resulted in the formation of strategic alliances with AstraZeneca and Sanofi and a research collaboration with Biogen focused on microRNA biomarkers. Regulus maintains its

corporate headquarters in La Jolla, CA. For more information, please visit http://www.regulusrx.com.

Forward-Looking Statements

Statements contained in this press release regarding matters that are not historical facts are forward-looking statements within the meaning of the

Private Securities Litigation Reform Act of 1995, including statements associated with financial estimates (including Regulus projected cash at the end of 2015), the projected sufficiency of Regulus capital position for future periods,

the expected ability of Regulus to undertake certain activities and accomplish certain goals (including with respect to development and other activities related to RG-101, RG-012 and RG-125), the projected timeline of clinical development

activities, and expectations regarding future therapeutic and commercial potential of Regulus business plans (including Regulus expected future activities in 2015), technologies and intellectual property related to microRNA therapeutics

and biomarkers being discovered and developed by Regulus. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Words such as

believes, anticipates, plans, expects, intends, will, goal, potential and similar expressions are intended to identify forward-looking statements. These

forward-looking statements are based upon Regulus current expectations and involve assumptions that may never materialize or may prove to be incorrect. Actual results and the timing of events could differ materially from those anticipated in

such forward-looking statements as a result of various risks and uncertainties, which include, without limitation, risks associated with the process of discovering, developing and commercializing drugs that are safe and effective for use as human

therapeutics, and in the endeavor of building a business around such drugs. These and other risks concerning Regulus financial position and programs are described in additional detail in Regulus filings with the Securities and Exchange

Commission. All forward-looking statements contained in this press release speak only as of the date on which they were made. Regulus undertakes no obligation to update such statements to reflect events that occur or circumstances that exist

after the date on which they were made.

Regulus Therapeutics Inc.

Selected Financial Information

Condensed Statement of Operations

(In thousands, except share and per share data)

Regulus Therapeutics Inc.

Condensed Balance Sheets

Harvoni is a registered trademark of Gilead Sciences,

Inc., Olysio is a registered trademark of Janssen Therapeutics and Daklinza is a trademark of Bristol-Meyers Squibb.

Investor Relations Contact:

Senior Director, Investor Relations and Corporate Communications

Regulus Therapeutics Inc.