Bone drug Zometa helps shrink breast tumors: study

CHICAGO (Reuters) - The Novartis bone-strengthening drug Zometa may enhance the effects of chemotherapy, shrinking breast tumors and helping more women avoid a mastectomy, British researchers said on Thursday.

Their study added to other findings that showed Zometa, which is typically used to fortify bones and prevent fractures in cancer patients, can prevent tumors from spreading.

"This is the first patient-related evidence that this class of drugs may have direct anti-tumor activity," said Dr. Robert Coleman of the University of Sheffield in Britain, who presented the findings at a breast cancer meeting in San Antonio, Texas.

Coleman and colleagues found that adding Zometa to chemotherapy before surgery made tumors shrink more.

The study involved 205 women with early stage breast cancer who were split into two groups.

One group got Zometa in combination with chemotherapy, and another got chemotherapy alone. The treatment was aimed at reducing the size of the tumor before surgery.

Women who got Zometa with chemotherapy before surgery appeared to have a 33 percent greater reduction in the size of their primary tumor than those who got chemotherapy alone.

And 65.3 percent of the women in the combination group needed a mastectomy, compared with 77.9 percent in the chemotherapy-only group.

Known generically as zoledronic acid, Zometa is in a class of bone-strengthening drugs known as bisphosphonates. Breast and other cancers commonly spread to the bone and patients can be crippled by the pain and fractures that result.

"What these data suggest is perhaps zoledronic acid is doing something more than just affecting bone," Coleman said in a telephone briefing.

Coleman said the results are not enough to change medical practice, but are likely to promote more exploration of the drug as a cancer fighter.

The analysis was part of a larger study called Azure evaluating the combination treatment in 3,360 women with breast cancer. Final results from the overall study are expected in the next two to three years.

(Reporting by Julie Steenhuysen; Editing by Maggie Fox and Philip Barbara)