Cancer drug olaparib shows early promise

A novel therapy designed to exploit the renegade power of malignant cells showed remarkable effectiveness against advanced ovarian and breast cancer in two small international studies.

One breast cancer patient who was terminally ill, the most remarkable case of all, continues to enjoy a complete remission of her disease two years after participating in one of the studies at the University of Pennsylvania.

"It's just so amazing," said Patricia Buckles, 61, of Memphis. "It's given me two years of my life that traditional chemotherapy could not. I'll stay on it, Lord willing, as long as my cancer stays asleep."

The experimental drug, a capsule called olaparib, works by making cancer cells even more genetically unstable than they already are. The cancer cells become too defective to survive, like a wobbly chair with only three legs that loses another leg.

Olaparib is being developed by AstraZeneca P.L.C., which has its U.S. headquarters in Wilmington. The company-funded studies were published online last week in the Lancet. But at least five other pharmaceutical companies are racing to develop their own "PARP inhibitors" because the new class promises to work against several kinds of cancer, and to have more tolerable side effects than conventional chemotherapies.

The new studies, led by Andrew Tutt of King's College London School of Medicine, involved researchers from 18 medical centers around the world, including Penn for breast-cancer patients.

Patients, who received either a high or low dose of olaparib, had better response rates on the high dose - another sign that the drug is effective.

All the patients had run out of standard treatment options, and their cancers had metastasized to other organs.

Of 27 breast-cancer patients who got a high dose of olaparib, 11 (41 percent) had tumor shrinkage, and 12 (44 percent) had no tumor growth for at least 23 weeks of the first 24 weeks of study. Of the 27 women on the lower dose, six had tumor shrinkage and 12 had stable disease.

Study coauthor Susan Domchek, director of Penn's Cancer Risk Evaluation Program, called it "an enormous response rate" considering that the women had received at least three prior chemotherapies.

The ovarian cancer study has 33 high-dose patients, of whom 11 (33 percent) had tumor shrinkage and 12 (36 percent) had stable disease. Among 24 low-dose patients, 3 had tumor shrinkage, and 7 had stable disease.