Peregrine rose 80 percent to $2.43 at the close in New York, the biggest single-day increase since October 2001. The shares have gained 167 percent in the past 12 months.

An internal review found that discrepancies in a mid-stage study were limited to the placebo and low-dose treatments, the Tustin, California-based biotechnology company said Monday in a statement. There were no issues with the higher 3 milligram dose that was shown last year to double survival from non-small cell lung cancer. Peregrine had said the positive results were unreliable because of questions about the treatment codes assigned to individual patients.

The review of the study from the second of three phases needed for U.S. Food and Drug Administration approval shows bavituximab has a “favorable” tumor response rate and overall survival when the high dose is compared to a combination of the low-dose and placebo arms, the company said. Peregrine didn’t provide updated results. More details about the findings will be given once the re-analysis is complete, the company said.

“We believe that these results of our internal review and subsequent data analysis support advancing bavituximab into Phase III development for the treatment of second-ling non-small cell lung cancer,” said Joseph Shan, vice president of clinical and regulatory affairs at Peregrine. “We are now preparing for discussions with the FDA and worldwide regulatory agencies.”