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ESMO 2016: Fulvestrant Improves Progression-Free Survival in Advanced Breast Cancer

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Key Points

  • After a median follow-up of 25 months, patients treated with fulvestrant had a statistically significant 21% improvement in progression-free survival compared to those treated with anastrozole (16.6 vs 13.8 months).
  • Subgroup analysis showed an even greater impact on progression-free survival in patients whose disease had not spread to the liver or lungs at baseline (22.3 vs 13.8 months).
  • Both groups showed a similar health-related quality of life, and the most common adverse events were arthralgia (16.7% vs 10.3%) and hot flashes (11.4% vs 10.3%) for fulvestrant and anastrozole, respectively.

Fulvestrant (Faslodex) significantly increases progression-free survival in women with hormone receptor–positive advanced breast cancer, particularly those with less aggressive lower-volume disease, Ellis et al reported at the 2016 European Society for Medical Oncology (ESMO) Congress in Copenhagen (Abstract LBA14_PR).

Fulvestrant is a selective estrogen receptor degrader that targets the function of the hormone receptor. Unlike aromatase inhibitors such as anastrozole, it does not interfere with estrogen levels themselves.

FALCON Trial

The randomized, double-blind, multicenter phase III FALCON trial enrolled 462 women with inoperable locally advanced or metastatic estrogen receptor (ER)–positive, HER2-negative breast cancer who had not received prior hormone therapy. Half the patients (n = 230) were randomized to 500-mg intramuscular injections of fulvestrant (days 0, 14, 28; then every 28 days), or to 1 mg of anastrozole daily (n = 232) and were also allowed one line of chemotherapy.

After a median follow-up of 25 months, patients treated with fulvestrant had a statistically significant 21% improvement in progression-free survival compared to those treated with anastrozole (16.6 vs 13.8 months, P = .048). However, subgroup analysis showed an even greater impact on progression-free survival in patients whose disease had not spread to the liver or lungs at baseline (22.3 vs 13.8 months).

“For patients with nonvisceral disease whose life isn’t immediately threatened by breast cancer—a group for whom physicians would typically choose endocrine therapy as a first approach—it looks like fulvestrant could be a new standard of care compared to anastrozole,” said the study’s principalma investigator Matthew Ellis, PhD, MB, BCh, of the Lester and Sue Smith Breast Center at Baylor College of Medicine.

Both groups showed a similar health-related quality of life, and the most common adverse events were arthralgia (16.7% vs 10.3%) and hot flashes (11.4% vs 10.3%) for fulvestrant and anastrozole, respectively.

“It’s tolerated as well as anastrozole and better than other drugs that could potentially be used in this setting, such as chemotherapy or CDK4 inhibitors,” Dr. Ellis said.

“In patients for whom you are looking for a low-toxicity approach, such as older patients or those with low-volume disease, it looks like a good option.”

Researchers also observed a significantly greater duration of response to treatment in the fulvestrant group compared to the anastrozole group, which Dr. Ellis suggested could account for the increase in progression-free survival.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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