Spectrum Pharmaceutical (SPPI) - Get Report lost more than half its market value Thursday after the biopharma reported that a Phase II trial for a drug designed to treat the most common form of lung cancer had not met its primary endpoint.

Spectrum said in a statement that poziotinib, its proposed drug to treat non-small-cell lung cancer, failed to meet "its pre-specified primary endpoint" in its Phase II clinical trial.

At last check Spectrum Pharma shares were off 56% at $3.86.

For the Zenith20 trial Spectrum enrolled 115 patients, each of whom received 16 milligrams a day of poziotinib. Seventeen patients had a positive response, while another 62 had "stable disease" for a 68.7% control rate, the company said.

Spectrum said it would continue to analyze the results, arguing that it had reasons to be encouraged.

"While the response rate of Cohort 1 was lower than we expected, the positive signals observed for this cohort provide support for the continued clinical evaluation of poziotinib in this patient population with significant, unmet medical need," said Joe Turgeon, president and CEO of Spectrum, in the statement.\

The company said it would provide "readouts from Cohorts 2 and 3 in 2020, and plans to provide an update on the overall program strategy during the first quarter of 2020 after a full evaluation of the data from Cohort 1 is completed."

The Irvine, Calif., biopharma also said Thursday that the U.S. Food and Drug Administration had accepted its proposed drug Rolontis for review. 

The FDA has set a target action date of Oct. 24, 2020, for the new drug. Rolontis is used to treat chemotherapy-induced neutropenia, or low white-blood-cell count.

Spectrum said its biologics license application for the drug is supported by two successful Phase III trials involving 643 early-stage-breast-cancer patients.

"We have confidence in the future of Rolontis," Turgeon said.