Shares of Arena Pharmaceuticals rose Tuesday after the drug developer said it received an additional patent for its weight loss drug Belviq.

Arena and its partner Eisai said approval was granted from the US Patent and Trademark Office. The patent can prevent other companies from producing a similar drug. The patent is expected to last until 2033, Arena CEO Jack Lief said in a written statement.

Belviq is designed to stimulate serotonin receptors in the brain, making patients feel full. The drug first went on sale in 2013.

San Diego-based Arena Pharmaceuticals Inc. makes and developed Belviq, while Eisai Inc., the U.S. unit of Japanese health company Eisai Co., markets the drug.

Arena shares rose 23 cents, or 5.3 percent, to $4.59 in morning trading Tuesday. Its shares are down 28 percent over the past year.