Top Developments in Breast Cancer Research Shape the MBCC Agenda

Anita T. Shaffer @Shaffer1
Published: Friday, Mar 08, 2019

Debu Tripathy, MD

Debu Tripathy, MD

The breast cancer field is experiencing rapid advancements in the understanding of disease biology and the development of novel therapeutic strategies for several subtypes, with a clear direction toward personalized or precision medicine, according to Debu Tripathy, MD.

That means the experts who are sharing their insights at the 36th Annual Miami Breast Cancer Conference® (MBCC) will have plenty to discuss throughout the 4-day gathering. Tripathy, one of the program cochairs for this year’s conference, reviewed key trends and developments, including some with the potential to change practice, in an interview in advance of the event.

During the past year, FDA decisions have expanded options for patients with breast cancer in several ways, through, for example, the approvals of the first and second PARP inhibitors for this tumor type, additional indications for CDK4/6 inhibitors, and 2 trastuzumab biosimilars (Table).

Tripathy, professor and chair of the Department of Breast Medical Oncology at The University of Texas MD Anderson Cancer Center in Houston, emphasized some of the recent clinical findings that are shaping standards of care.

“It’s been a banner year for new drugs, new approvals, [and] new concepts,” said Tripathy. “The pace of development has really picked up. A lot of that is because we have newer technology to analyze these tumors at the genomic level, at the RNA level, [and] at the gene expression level with immunohistochemical tests and ‘multiplex/multiomics’ studies. It’s becoming much more feasible to do these very ambitious, multiparametric studies on multiple samples over time to really get a picture of what’s going on and to apply this information toward new and more innovative strategies. This is a consequence of having a much more robust set of tools to interrogate tumors.”

The knowledge gained thus far underscores the need to incorporate tissue collection and analysis into clinical trials for new drug regimens, Tripathy said. “It used to be that we studied the biology separately in the laboratory and then we developed treatments empirically,” he said. “But now that we’re starting to get more sophisticated drugs that work specifically in certain types of breast cancers, breast cancers are being increasingly segregated into different biologically and clinically relevant genotypes and phenotypes. The key thing is we have to study both clinical and biological outcomes at the same time.”

Table. A Timeline of Recent FDA Approvals in Breast Cancer

Table. A Timeline of Recent FDA Approvals in Breast Cancer

Early-Stage Breast Cancer

Hormone Therapy in Premenopausal Women

In terms of hormonal therapy, long-term results of 2 large clinical trials, SOFT and TEXT, confirmed the benefit of adding ovarian function suppression to 5 years of tamoxifen or exemestane for premenopausal women with hormone receptor (HR)–positive breast cancer.

In SOFT, the 8-year disease-free survival (DFS) rate was 78.9% with tamoxifen alone, 83.2% with tamoxifen plus ovarian suppression, and 85.9% with exemestane plus ovarian suppression. The 8-year rates of overall survival (OS) for the treatment arms were 91.5%, 93.3%, and 92.1%, respectively. The impact of ovarian suppression was greatest in patients with higher risk, such as those who required chemotherapy. The trial randomized 3047 patients, most of whom (84.9%) were HER2-negative, to 1 of the 3 treatment arms. Ovarian suppression consisted of triptorelin, bilateral oophorectomy, or ovarian irradiation.1

In TEXT, 2672 patients were randomized to receive 5 years of triptorelin with either exemestane or tamoxifen, with bilateral oophorectomy or ovarian irradiation 6 months after starting triptorelin.

After a median follow-up of 9 years, investigators analyzed the combined population of the 2 studies and found that exemestane plus ovarian suppression resulted in an 8-year DFS rate of 86.8% compared with 82.8% with tamoxifen (hazard ratio, 0.77; 95% CI, 0.67-0.90; P <.001).1 The DFS advantage with exemestane was greater compared with tamoxifen in patients who also received adjuvant chemotherapy because of a higher risk of recurrence, but with no difference in overall survival.

The findings “confirm that especially in high-risk patients, there is an added benefit of ovarian suppression,” Tripathy said. “That now has become a new standard of care and is incorporated into the most recent guidelines.”

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