FDA advisers back Glaxo, Genmab cancer drug

By Deena Beasley

ORLANDO, Florida (Reuters) - A small trial of Arzerra, being developed by GlaxoSmithKline Plc and Genmab for treating chronic lymphocytic leukemia, indicated benefits sufficient for U.S. approval, an advisory committee to regulators said on Friday.

The panel voted 10-3 that the trial results were likely to predict clinical benefit in patients with CLL, a common type of blood cancer in adults. One member abstained from the voting.

Initially, the companies are seeking U.S. Food and Drug Administration approval for patients who have failed two other treatments -- fludarabine and alemtuzumab -- and others who have failed fludarabine and for whom alemtuzumab, sold by Genzyme as Campath, was inappropriate because of their bulky tumors.

"I am impressed by the resolution of symptoms," said Dr Margaret Tempero, deputy director at the University of California at San Francisco's cancer center and a member of the advisory committee. "I also thought the overall survival benefit looked encouraging."

Glaxo and Genmab are seeking accelerated approval of Arzerra, based on results from a small trial that did not include a comparison arm.

Much of the discussion at the panel hearing centered on whether new criteria requiring that tumors be measured with CT scans should be applied to the Arzerra trial.

Analysts believe annual sales of Arzerra could eventually top $2 billion, although the drug is unlikely to reach its full potential until the middle of the next decade. The makers are studying larger populations beyond CLL.

A clinical trial showed a 58 percent response rate to Arzerra in patients who failed the two prior chemotherapy regimens, a higher level than the normal 25 percent level, Glaxo spokeswoman Lisa Behrens said.

The median duration of response for patients in the trial was 6.5 months.

Infections, including fatal ones, were seen frequently in the study but it was not possible to determine how much infection risk was due to the drug, FDA staff said. Heavily treated CLL patients normally have high infection rates.

Glaxo officials said two larger Phase III trials of Arzerra are being launched, but it will be roughly five years before those results are available.

London-based Glaxo bought global rights to Arzerra in a December 2006 deal worth up to $2.1 billion, a record sum for a biotech product agreement at the time.

(Additional reporting by Lisa Richwine; Editing by Tim Dobbyn)