Trius Therapeutics Added to the NASDAQ Biotechnology Index

SAN DIEGO, May 14, 2012 (GLOBE NEWSWIRE) — Trius Therapeutics, Inc. (Nasdaq:TSRX), a biopharmaceutical company focused on the discovery, development and commercialization of innovative antibiotics for life-threatening infections, announced today that the Company will be added to the NASDAQ Biotechnology Index® (NBI). The semi-annual re-ranking of the index will become effective prior to market opening on Monday, May 21, 2012.

“We are pleased to be included among the leading biotechnology and pharmaceutical companies that make up the NASDAQ Biotechnology Index,” stated Jeffrey Stein, Ph.D., President and Chief Executive Officer of Trius. “In addition to our inclusion in the Russell 2000® Index last year, this selection highlights Trius’ continued progress and consistent achievement of our corporate objectives.”

The NBI was launched in 1993 and includes securities of biotechnology and pharmaceutical companies listed on the NASDAQ that meet minimum requirements, including market value, average daily share volume, and seasoning as a public company, among other criteria. The index is ranked on a semi-annual basis in May and November and serves as the basis for the iShares NASDAQ Biotechnology Index Fund (Nasdaq:IBB). For more information about the NBI including eligibility criteria, visit https://indexes.nasdaqomx.com/docs/methodology_NBI.pdf.

About Trius Therapeutics

Trius Therapeutics, Inc. is a biopharmaceutical company focused on the discovery, development and commercialization of innovative antibiotics for life-threatening infections. The Company’s lead investigational drug, tedizolid phosphate, is a once daily, IV and orally administered second generation oxazolidinone in Phase 3 clinical development for the treatment of ABSSSI. Trius has two Special Protocol Assessments with the FDA for its two Phase 3 ABSSSI trials and has partnered with Bayer HealthCare for the development and commercialization of tedizolid phosphate outside of the U.S., Canada and the European Union. In addition to the Company’s tedizolid phosphate clinical program, Trius has initiated IND-enabling studies for its Gyrase-B development candidate with potent activity against Gram-negative bacterial pathogens including multi-drug resistant strains of E. coli, Klebsiella, Acinetobacter and Pseudomonas. The Gyrase-B program is one of the two preclinical programs supported by federal contracts. For more information, visit www.triusrx.com.

CONTACT: Public Relations Contact:

Jason Spark at Canale Communications, Inc.

jason@canalecomm.com

619-849-6005

Investor Relations Contact:

Stefan Loren at Westwicke Partners, LLC

sloren@westwicke.com

443-213-0507