AbbVie leukemia drug impresses in early-stage trial

Reuters

By Ransdell Pierson

Dec 8 (Reuters) - An experimental AbbVie Inc drugfor leukemia controlled or eliminated signs of the disease inmore than 80 percent of patients who had failed to benefit fromprevious treatments, an unprecedented finding that could spuruse of the medicine for other cancers, researchers said.

The AbbVie drug, ABT-199, works by blocking a protein calledBCL-2 that allows cancer cells to overcome a natural mechanismcalled programmed cell death, in which the body kills offdefective or cancerous cells.

AbbVie is developing the once-daily pill in partnership withRoche Holding AG.

The favorable data was seen in a phase I, or early-stage, trial involving 67 patients with chronic lymphocytic leukemiawho had not been helped by chemotherapy or relapsed from suchtreatment.

The slowly progressing blood cancer, which mainly affectspeople age 65 and older, occurs when white blood cells build upin the blood, bone marrow and lymph nodes, causing them toenlarge. About 15,000 Americans are diagnosed with the diseaseeach year.

Some 84 percent of patients who took ABT-199 stronglyresponded to the drug, with at least a 50 percent reduction insigns of the disease. And 23 percent had complete remissions,meaning all signs of the disease vanished.

"To achieve that magnitude of complete remission isextraordinarily promising and unprecedented in this particulartype of leukemia, among patients with otherwise resistantdisease," Dr. John Seymour, a researcher with the PeterMacCallum Cancer Centre in Melbourne, Australia, said in atelephone interview.

Seymour is scheduled to present data from his trial onTuesday at the annual meeting of the American Society ofHematology (ASH) in New Orleans.

In the ongoing study, 72 percent of patients remain on thedrug and are well at or beyond 12 months of treatment, Seymoursaid.

Seymour said patients with chronic lymphocytic leukemia thathave failed to respond to therapy typically only live another 12to 18 months. He said it was too early to say how patients inhis trial would fare.

One patient in the trial died from a complication oftreatment, called tumor lysis syndrome, in which killed cancercells build up in the bloodstream.

But Seymour said dosages of the drug are now slowlyincreased during the first few weeks of treatment, a change thathas markedly decreased the lysis risk.

Otherwise, he said ABT-199 was very well tolerated, withgenerally mild side effects such as nausea and diarrhea.

"For decades BCL-2 has been a sought-after target, but upuntil now no other drugs have had the potency and precision ofABT-199," Seymour said.

He said other malignancies, including cancers of the breast,prostate and lung, are also fueled by BCL-2, and that ABT-199may therefore have promise in treating them.

"This compound has that potential, but we're still at thevery early stages of testing it," Seymour said. "We're crawling,but we're looking forward to where we may be running in thefuture."

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