FDA staff questions Cell Therapeutics drug data

WASHINGTON (Reuters) - U.S. drug reviewers questioned effectiveness data from Cell Therapeutics Inc for an experimental lymphoma drug and said the medicine carried substantial side effects, according to documents released on Monday.

The Seattle-based biotechnology company is seeking approval to sell pixantrone under the brand name Pixuvri for treating non-Hodgkin's lymphoma that has stopped responding to other treatments.

Food and Drug Administration reviewers, in an analysis prepared for an advisory committee, said issues raised in their review included "the reliability of (efficacy) conclusions" and "substantial hematologic and cardiac toxicity."

They said they would ask the advisory panel at a meeting on Wednesday whether the company had provided enough evidence that pixantrone worked and whether the benefits outweighed risks.

Cell Therapeutics, in a separate summary prepared for the panel, said its data showed pixantrone worked better than comparison drugs with "manageable toxicities."

(Reporting by Lisa Richwine, editing by Gerald E. McCormick)