(Updated with stock price) WASHINGTON ( TheStreet) --Drug reviewers working for the Food and Drug Administration raised concerns about the efficacy and safety of Cell Therapeutics' ( CTIC - Get Report) lymphoma drug pixantrone drug, according to a review of the drug posted to the agency's Web site Monday. Shares of Cell Therapeutics fell 30% to 73 cents a share in early Monday trading. Cell Therapeutics only enrolled 140 out of a planned 320 patients with aggressive, non-Hodgkin's lymphoma in its pivotal phase III study of pixantrone. As a result, the FDA raises doubts about "the level of evidence necessary to draw conclusions from this Phase 3 study and the reliability of these conclusions," according to the agency's review. The agency is also concerned about "substantial hematologic and cardiac toxicity" related to treatment with pixantrone. Cell Therapeutics's decision to halt enrollment early in the pixantrone study and analyze the data earlier than expected invalidated the Special Protocol Assessment (SPA) the company had with the FDA for the conduct of the study, according to the FDA's review. The small number of patients in the pixantrone phase III study, concerns over the heart safety of the drug and the lack of an SPA were all issues expected to be troublesome for Cell Therapeutics. The FDA is convening an advisory panel meeting on Feb. 10 to review pixantrone. Cell Therapeutics is trying to get the drug approved as a treatment for patients with advanced, aggressive non-Hodgkin's lymphoma. Cancer experts on the FDA's Oncologic Drugs Advisory Committee (ODAC) will be reviewing data from a phase III study of pixantrone known as "EXTEND" and voting on whether or not to recommend the drug's approval by the agency.
The FDA is expected to make its approval decision public on or before April 23. -- Reported by Adam Feuerstein in Boston. Follow Adam Feuerstein on Twitter.