Arena Pharmaceuticals Earns Prime Status from ISS ESG, a Leading Rating Agency for Sustainable Investments

Arena Pharmaceuticals, Inc. (Nasdaq: ARNA) today announced it has been designated Prime in the ISS ESG Corporate Rating, effective as of May 4, 2021. Companies are classified as Prime when their ESG performance exceeds the threshold criteria for companies in its sector, meaning they fulfill ambitious absolute performance requirements.

The ISS ESG Corporate Rating sets the industry standard for sustainable investing and is used by international institutional investors and financial service companies to inform their decisions. According to this rating, Arena tradeable bonds and shares will now qualify for responsible investment.

"This rating reinforces our far-reaching efforts to build a vibrant, sustainable enterprise with the ultimate goal of delivering our important medicines to patients who need them," said Laurie Stelzer, Chief Financial Officer of Arena Pharmaceuticals. "Our management team, our employees, and our Board of Directors all embrace a long-term commitment to ESG principles for the betterment of our company and the communities we are working in. We are proud to be recognized as not only a sustainable company, but also a sustainable investment."

The Prime status follows the release of Arena's second annual ESG report in April 2021, outlining the Company's long-term commitment to the betterment of society, focusing on patients, employees, the community, the environment, and shareholders.

For more information on the ISS ESG Corporate Rating, please visit: issgovernance.com/esg/ratings/.

View the full 2021 Arena ESG Report on the Arena Investors page: https://invest.arenapharm.com/.

About Arena Pharmaceuticals

ARENA Pharmaceuticals is a team with a singular purpose ? deliver important medicines to patients.

In a rapidly changing global market, we work with a sense of urgency every day to understand the needs of all our stakeholders, identify bold, sometimes disruptive, ideas to get medicines to patients, and relentlessly execute until it's done.

We are developing a richly diversified portfolio of therapeutic candidates targeting gastroenterology, dermatology and cardiology. Our pipeline includes four investigational medicines in eight indications and eleven ongoing or planned clinical trials. To fuel our growth, we are unlocking the value of our historical GPCR research with a sustainable discovery engine for broad portfolio expansion.

ARENA - Care More. Act Differently.

Forward-Looking Statements

Certain statements in this press release are forward-looking statements that involve a number of risks and uncertainties. Such forward-looking statements may be identified by words such as "will," "efforts to," "long-term," "commitment," "purpose," "targeting," and "planned," and include, without limitation, statements about Arena's ESG initiatives, purpose, work, understanding, ideas, execution, portfolio, and discovery engine. For such statements, Arena claims the protection of the Private Securities Litigation Reform Act of 1995. Actual events or results may differ materially from Arena's expectations. Factors that could cause actual results to differ materially from the forward-looking statements include those disclosed in Arena's filings with the Securities and Exchange Commission (SEC), including but not limited to Arena's Quarterly Report on Form 10-Q for the quarter ended March 31, 2021, which was filed with the SEC on May 5, 2021. These forward-looking statements represent Arena's judgment as of the time of this release. Arena disclaims any intent or obligation to update these forward-looking statements, other than as may be required under applicable law.