Shares of drug developer Genta ( GNTA) sank 24.5% to 52 cents Friday after the company announced that regulators have deemed its proposed blood cancer treatment Genasense not approvable. The drug was intended to treat chronic lymphocytic leukemia, in combination with chemotherapy. Shares of drug developer Biopure ( BPUR) plummeted 27% to 43 cents after a Food and Drug Administration panel recommended against a clinical trial as currently designed. The agency's blood products advisory committee voted 11 to 8, with one abstention, against an 1,100-patient trial in favor of a smaller safety and efficacy trial. Meanwhile, Critical Therapeutics' ( CRTX) shares gained 25.2% to $1.90 after the company announced that a study of its lung disease drug Zyflo will be funded by the National Institutes of Health. The trial is designed to evaluate whether the drug can help shorten hospital stays of patients admitted with acute exacerbations of chronic obstructive pulmonary disease. The trial is expected to begin in the first quarter of 2007. Genzyme's ( GENZ) shares rose 3.3% to $63.07 Friday after the company said its arthritis treatment Synvisc will maintain its own reimbursement code and rate in 2007. The Centers for Medicare and Medicaid Services previously said all treatments like Synvisc would use the same billing code, a move that was expected to lower reimbursement for the knee injection.