Geron Corp said 22 percent of trial patients treated with its experimental blood cancer drug were now free of the disease, a major break for the company after two big setbacks.
Shares of Geron more than doubled in morning trade on Thursday to a four-year high.
"This is going to save the company, because it's the last thing that they had," MLV & Co analyst George Zavoico told Reuters. "This truly opens the door for other opportunities in other indications."
Geron earlier failed to develop the blood cancer drug, imetelstat, to treat breast cancer. It also stopped working on its brain cancer drug.
Imetelstat is designed to treat myelofibrosis, a rare form of blood cancer.
Zavoico said the data validated imetelstat's "mechanism of action" and suggested it was superior to Incyte Corp's Jakafi, which is approved to treat myelofibrosis.
Imetelstat is designed to inhibit telomerase, an enzyme that enables rapid multiplication of cancer cells.
Jakafi inhibits another family of enzymes, reducing cell multiplication. The drug had sales of $136 million in 2012.
Zavoico said Jakafi reduced spleen size and relieved symptoms, but did not have a disease-modifying effect, defined as partial or complete remission.
Geron said one patient of the first 18 enrolled in the trial showed partial remission.
The company released the data ahead of a presentation on December 9 at the annual meeting of the American Society of Hematology.
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