Novavax shares rose more than 4 percent at Tuesday's market open after the bio-pharmaceutical firm said its Ebola vaccine showed promising results in an early-stage trial.
Novavax said the Ebola GP Vaccine was well tolerated in the trial involving 230 healthy adults, and that it elicited very high Ebola antibody responses at all dose levels, the company said on Tuesday.
Read MoreEbola vaccine trials in Liberia
Several pharmaceutical stocks surged last year after the Center for Disease Control and Prevention confirmed the first U.S. case of the deadly disease. Tekmira Pharmaceuticals, which was working on a treatment, saw a more than 20 percent jump in after-hours trade following the announcement.
Despite early positive headlines, Tekmira said Monday that it would suspend its Ebola research, following an acknowledgement that its treatment would likely fail in a clinical trial.
Gaithersburg, Maryland-based Novavax's shares have risen more than 50 percent since Feb. 12, when the company said it began testing its Ebola vaccine in humans.
Other companies—including GlaxoSmithKline, NewLink Genetics, Johnson & Johnson and Inovio—are also working on experimental Ebola vaccines.
—The Associated Press and Reuters contributed to this report.