New drug combination delayed disease progression for subgroup of women with metastatic breast cancer

December 12, 2013

Adding the drug dasatinib to a standard antihormone therapy, letrozole, doubled the time before disease progressed for women with hormone receptor-positive, HER2-negative metastatic breast cancer, according to results of a phase II clinical trial presented here at the 2013 San Antonio Breast Cancer Symposium, held Dec. 10-14.

Dasatinib is approved by the U.S. Food and Drug Administration for the treatment of . One of the ways it works is by blocking the activity of a protein called Src, which has been recently implicated in the spread of breast cancer to bones.

"Patients with metastatic breast cancer desperately need new treatment options that can lengthen and improve the quality of their lives," said Dev Paul, D.O., Ph.D., breast oncologist at U.S. Oncology and Rocky Mountain Cancer Centers in Denver, Colo. "Because several studies have linked high levels of Src activity to to the bone, we wanted to see whether combining letrozole and dasatinib as first-line treatment for would improve the clinical-benefit rate and progression-free survival compared with letrozole alone.

"We are encouraged to see that the combination doubled progression-free survival time," he added. "But this was a small study, and we really need a biomarker to measure Src activity in breast tumors, so that we can better determine which patients will be most likely to benefit from the addition of dasatinib to letrozole."

Paul and colleagues enrolled 120 postmenopausal women with locally recurrent or metastatic hormone receptor-positive, HER2-negative breast cancer in the phase II clinical trial. They randomly assigned 63 participants to letrozole and 57 to letrozole plus dasatinib. The primary aim of the study was to determine whether adding dasatinib to letrozole increased the clinical-benefit rate. The clinical-benefit rate is the number of patients who had a complete response, plus the number who had a partial response, plus the number who had stable disease for six or more months.

The researchers found that adding dasatinib to letrozole did not increase the clinical-benefit rate compared with letrozole alone. When a second measure of the study's outcome was analyzed, the combination therapy was shown to dramatically improve progression-free survival. Progression-free survival for patients receiving dasatinib and letrozole was 20.1 months compared with 9.9 months for letrozole alone.

Patients receiving dasatinib plus letrozole did experience additional side effects but none were considered severe adverse events, according to Paul, and most patients tolerated the full dose of dasatinib.

"Although these data suggest that adding dasatinib to improves progression-free survival for postmenopausal women with hormone receptor-positive, HER2-negative metastatic , we would like to find a biomarker for Src activity in the breast before conducting larger clinical studies of this drug combination," said Paul.

Explore further: SABCS: PD 0332991 + letrozole studied in ER+ breast cancer

Related Stories

SABCS: PD 0332991 + letrozole studied in ER+ breast cancer

December 5, 2012
(HealthDay)—For women with estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer, the investigational agent PD 0332991 plus letrozole improves progression-free survival versus ...

Pfizer breast cancer drug gets breakthrough label

April 10, 2013
Pfizer Inc. says its experimental pill for advanced, often deadly breast cancer has been designated as a breakthrough therapy by the Food and Drug Administration.

Biomarker predicts risk of breast cancer recurrence after tamoxifen treatment

June 29, 2013
A biomarker reflecting expression levels of two genes in tumor tissue may be able to predict which women treated for estrogen-receptor (ER)-positive breast cancer should receive a second estrogen-blocking medication after ...

Optimal dose suggested for dasatinib in ovarian cancer

November 19, 2012
(HealthDay)—A phase I trial of dasatinib combined with paclitaxel and carboplatin has determined the optimal dose of dasatinib and suggested some efficacy in women with advanced or recurrent ovarian cancer, according to ...

Patients with metastatic breast cancer may not benefit from surgery and radiation after chemotherapy

December 11, 2013
After a response to initial chemotherapy, treatment with radiotherapy and surgical removal of the breast tumor and nearby lymph nodes do not provide any additional benefit to patients with metastatic breast cancer, according ...

High levels of immune cells in tumors may ID breast cancer pts most likely benefit from trastuzumab

December 11, 2013
Women with HER2-positive breast cancer who had the highest levels of immune cells in their tumors gained the most benefit from presurgery treatment with chemotherapy and trastuzumab, according to results presented here at ...

Recommended for you

Study uncovers potential 'silver bullet' for preventing and treating colon cancer

July 26, 2017
In preclinical experiments, researchers at VCU Massey Cancer Center have uncovered a new way in which colon cancer develops, as well as a potential "silver bullet" for preventing and treating it. The findings may extend to ...

Compound shows promise in treating melanoma

July 26, 2017
While past attempts to treat melanoma failed to meet expectations, an international team of researchers are hopeful that a compound they tested on both mice and on human cells in a petri dish takes a positive step toward ...

Understanding cell segregation mechanisms that help prevent cancer spread

July 26, 2017
Scientists have uncovered how cells are kept in the right place as the body develops, which may shed light on what causes invasive cancer cells to migrate.

Study may explain failure of retinoic acid trials against breast cancer

July 25, 2017
Estrogen-positive breast cancers are often treated with anti-estrogen therapies. But about half of these cancers contain a subpopulation of cells marked by the protein cytokeratin 5 (CK5), which resists treatment—and breast ...

Breaking the genetic resistance of lung cancer and melanoma

July 25, 2017
Researchers from Monash University and the Memorial Sloan Kettering Cancer Center (MSKCC, New York) have discovered why some cancers – particularly lung cancer and melanoma – are able to quickly develop deadly resistance ...

Physical activity could combat fatigue, cognitive decline in cancer survivors

July 25, 2017
A new study indicates that cancer patients and survivors have a ready weapon against fatigue and "chemo brain": a brisk walk.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.