Eli Lilly & Co. on Wednesday said U.S. regulators have approved its new antidepressant, Cymbalta, a drug that analysts say will be central to the company’s growth.

Lilly’s shares rose 2 percent to $64.50 in electronic pre-market trading.

The U.S. Food and Drug Administration said the highly anticipated drug is both safe and effective in treating major depression, the company reported in a statement.

Industry analysts expect Cymbalta (duloxetine) to generate peak annual sales of $2 billion, a much-needed boon for Lilly after sales of its former top-selling antidepressant, Prozac, plummeted in the face of generic competition.

Cymbalta works by maximizing the presence in the brain of two chemicals, serotonin and norepinephrine. In this respect, it is similar to Wyeth’s Effexor XR. Drugs like Prozac, Pfizer Inc.‘s Zoloft and GlaxoSmithKline Plc’s Paxil maximize the presence only of serotonin.

Cymbalta comes to the market at a time of growing uncertainty about new classes of antidepressants. Cymbalta came under scrutiny in February following the suicide of a 19-year-old college student involved in one of the company’s clinical trials. She was not depressed at the beginning of the trial.