The FALCON trial directly compared anastrozole with fulvestrant and showed a slight superiority of fulvestrant in terms of progression-free survival (PFS). In fact, in patients who did not have visceral disease—had bone-only or soft tissue disease—the outcome was significantly better. The important thing about this study is that it was done in patients who had not previously received endocrine therapy, including in the adjuvant setting. Most of the patients were de novo or hadn't had adjuvant therapy. That is one caveat about that trial; it is now raising the question of whether fulvestrant should be the partner with some of the biological drugs, such as CDK4/6 inhibitors.
One of the important things is preserving QOL and delaying the time patients may need to go on to chemotherapy if they're refractory to endocrine biotherapies. As more biological therapies come to the forefront, we’re hoping that we can delay the time that patients may need chemotherapy. If we cross the significant biological barriers and figure out why patients develop resistance to these drugs, we could push it out further and obviate the need for the more toxic therapies altogether.
How have the TAILORx results informed management of the disease and affected chemotherapy's relevance in the treatment paradigm?
Shifting to early-stage breast cancer, endocrine therapy is clearly important for patients who have HR-positive disease. One of the big questions is, “Who needs chemotherapy and how much do they benefit from it?” This is particularly true in lower-risk cancers, specifically patients who have node-negative disease.
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