Amgen Inc. shares rose nearly 3 percent on Wednesday after the company released positive study results for a “biosimilar” drug that would compete against Humira, a blockbuster produced by a competitor.

The Thousand Oaks biopharmaceutical said its drug, ABP 501, performed well in a Phase Three human clinical trial as a treatment for plaque psoriasis, which causes itching, flaking and redness on the skin.

Humira, manufactured by AbbVie Inc., in North Chicago, had sales of about $10.7 billion last year but its patent protection will start to expire in 2016, allowing Amgen to market a biosimilar drug.

Biosimilars are medicines made by living cells that try to copy proprietary drugs when their patent protection expires. Because small differences in environment or manufacturing processes may alter the final product, the drugs are called similar – but not identical – to the original drug.

AbbVie has approvals to market Humira for psoriasis and other inflammatory diseases, including rheumatoid arthritis, Crohn's disease and ulcerative colitis.

Shares of Amgen closed up $4.04 to $140.07 on the Nasdaq.