Bayer Pharmaceuticals Corp. and Onyx Pharmaceuticals Inc. said Monday that they stopped a successful clinical trial for a liver cancer treatment and will seek global marketing approval.

Shares of Onyx jumped $5.74, or 46.8 percent, to $18 in electronic premarket activity, after closing at $12.26 Friday on the Nasdaq. Shares have traded between $10.38 and $29.10 over the past 52 weeks. American depositary shares of Bayer's parent rose 21 cents to $58.04.

West Haven, Conn.-based Onyx and the Emeryville, Calif-based unit of German drugmaker Bayer AG said a data monitoring committee determined that study data showed Nexavar, or sorafenib, significantly increased the survival rate in patients with advanced liver cancer compared with patients taking a placebo. The committee also found no significant difference in side effects between Nexavar and the placebo.

Based on the findings, the companies will stop the trial early and allow all patients in the study access to the drug.

The companies said they will approach the Food and Drug Administration and European regulators to try to get Nexavar approved as quickly as possible given the limited available therapies for advanced liver cancer.

Bayer and Onyx said they will release results of the trial at a major cancer meeting in June.