Shares of drug developer Genta Inc. dropped sharply Tuesday after the Food and Drug Administration questioned whether its leukemia treatment candidate would offer any substantial improvement over chemotherapy.


The comments were released a briefing from the FDA ahead of an Oncology Drug Advisory Committee review of Genasense, scheduled for Wednesday. Genta is seeking approval for the drug, to be injected in conjunction with chemotherapy to treat a form of the blood cancer called refractory chronic lymphocytic leukemia.

The company's stock sank fell 53 cents, or 38 percent, to close at 86 cents per share on the Nasdaq, as trading volume skyrocketed to more than 40 million shares. Average trading volume is approximately 2.2 million shares. Also, the stock touched off a new 52-week low of 75 cents a share, beating the previous low of $1.07 set a year ago. Shares traded as high as $3.48 Feb. 6.

"The study approached, but did not quite achieve statistical significance for its primary endpoint," the company said, in a summary it filed with the FDA.

The FDA in its summary said while trial results showed the difference in treatments is greater, it is "of questionable clinical significance."

The response rate, or complete response to the treatment, was 17 percent, compared with a 7 percent response rate for chemotherapy alone. That falls short of a 20 percent rate of remission goal. Also, the median survival rate for patients in the 223-person study on a combination of Genasense and chemotherapy was 33.8 months. The group solely on chemotherapy had a median survival rate of 32.9 months.

Genta requested a "Fast Track" approval in December, citing the drug candidate would address an unmet need.

GNTA shares are currently halted from trading on the Nasdaq.