Shares of cancer drug developer CytRx Corp. spiked Tuesday after the company announced positive results from a trial for one of its drugs.

A test of aldoxorubicin found that it could be an effective treatment for certain brain tumors, the West Los Angeles company announced.

The trial, conducted in partnership with Louisiana State University, used animal tests. The results will be presented at an Amsterdam conference in September.

“This trial produced remarkable results in a deadly cancer that virtually always returns regardless of whether treated with surgery, radiation, chemotherapy or a combination of methods,” Steven A. Kriegsman, president and chief executive, said in a statement. “Animals treated with aldoxorubicin survived on average more than twice as long as those treated with saline or doxorubicin, a relative of aldoxorubicin.

Shares were up 21 percent to $2.66 in Tuesday trading on the Nasdaq.