US firm, Cell Therapeutics, lost more than half of its value during trading on the Nasdaq Stock Exchange yesterday after the company revealed that its experimental oncology agent, Xyotax, failed to meet its primary endpoint of improved efficacy over standard chemotherapy in a late-stage non-small cell lung cancer trial. The firm’s share price plunged by as much as 55% on the news.

The trial, known as Stellar 3, pitted Xyotax in combination with carboplatin, against Bristol-Myers Squibb’s anticancer agent, Taxol (paclitaxel), also in combination with carboplatin, in 400 NSCLC patients. On the bright side for Cell Therapeutics, patients who received the Xyotax/carboplatin regimen had significantly less hair loss and a reduction in other side effects, including muscle and joint pain and heart symptoms. The full trial data will be presented at the American Society of Clinical Oncology meeting in the middle of May.

“We are disappointed that Xyotax in combination with carboplatin showed equal efficacy after the unprecedented blended median and one-year survival we saw on the trial,” James Bianco, CTI’s president and chief executive said in a statement. “We are encouraged by the preliminary analysis, which demonstrates a significant Xyotax treatment effect, reduction in toxicities, and increased patient convenience.”