Shares of Amgen Inc. jumped 15 percent Wednesday after the Thousand Oaks-based biotechnology company beat analysts’ estimates for second-quarter earnings and raised its financial outlook for the year.

Piper Jaffray senior research analyst Mark Karvosky raised his outlook on Amgen on the news to “outperform,” from “market perform” citing the company’s strong second-quarter earnings.

Hamed Khorsand, president of BWS Financial in Granada Hills, raised his price target on Amgen to $85 a share.

Khorsand said Amgen is being driven by strong demand for its arthritis drug Enbrel, which received recent approval from the Food and Drug Administration for treatment of people with psoriatic arthritis, an inflammatory disease of the joints and skin.

Sales of Enbrel rose 45 percent in the second quarter to $639 million, outpacing strong sales of Amgen’s other drugs including anemia treatment Aranesp, whose sales rose 36 percent, and white blood-cell booster Neulasta, with sales up 25 percent.

“Over the past year, Amgen received wider labeling from the FDA for Enbrel, which has been fueling their growth,” said Khorsand. “That was the standout winner this quarter.”

Amgen reported net income late Tuesday of $1 billion (82 cents per diluted share) for the second quarter ended June 30, compared with $748 million (57 cents) for the like period a year ago. Revenue rose 23 percent to $3.2 billion.

Khorsand said he expects Amgen will get FDA approval in 2006 for a cancer treatment, Panitumumab, which is in Phase 3 clinical trials.