Sunesis Pharmaceuticals, Inc.'s Flop: More Drugs Out There, Says Roth

Sunesis Pharmaceuticals, Inc.'s SNSS failed cancer drug vosaroxin offers no reason for investors to give up hope on other companies' potential cures, an analyst said Tuesday.

Sunesis said Tuesday its vosaroxin drug for acute myeloid leukemia failed to show effectiveness in a trial with nearly 800 patients. The company's shares opened Tuesday down about 80 percent from the preceding closing price.

But Roth analyst Joseph Pantginis prescribed several other companies touting unproven treatments for the blood disease, which accounts for about 1.2 percent of U.S. cancer deaths annually.

Their drugs, Pantginis said, are "using differentiated mechanisms of action." In other words, they're not the same as vosaroxin which was supposed to act on a DNA-related enzyme.

MEI Pharma Inc., for example, wants to apply pracinostat, a compound historically used by psychiatrists for mood disorders, as a means of treating leukemia by inhibiting an entirely different DNA-related enzyme.

Celator Pharmaceuticals Inc.'s CPX-351 has been granted orphan drug status by the U.S. Food and Drug Administration for the treatment of the disorder. It's an injectable combination of cytarabine and daunorubicin.

Also, Stemline Therapeutics Inc.'s SL-401 showed promise against leukemia in a recent Phase I-II study.

And Aptose Biosciences Inc. is planning a Phase 1b clinical study of its APTO-253 leukimia treatment, followed by two disease-specific expansions planned in adults with hematologic malignancies in 2014.