Atara Biotherapeutics Inc. capped off a strong week with a soaring stock price on Friday, when shares of the biopharmaceutical firm rose nearly 30 percent to a two-year high.

Atara’s stock price began its double-digit rise on Wednesday when the company announced it had received approval from the Food and Drug Administration to launch Phase 1 clinical trials on a new drug for multiple sclerosis. After closing up around 10 percent on Jan. 10, its stock rose another 20 percent on Jan. 11, bringing it to about $22 a share.

Atara (ATRA) gained $6.10 on Friday to close at $28.25 on the Nasdaq, and continued to rise in after-hours trading.

The company is headquartered in South San Francisco but runs its research and development operations in Thousand Oaks. It specializes in the creation of immunotherapies, which recruit the body’s own immune system to combat disease. Atara currently has six drugs in various stages of development, including treatments for blood cancers, solid tumors, autoimmune conditions and infectious diseases.