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34
th
Annual Miami Breast
Cancer Conference
9–12 MARCH 2017 • MIAMI BEACH, FLORIDA, USA
“Lightning rounds” capped off an eventful 34th Annual
Miami Breast Cancer Conference, providing a roundup of
key sessions and take-aways for metastatic breast cancer
presented at this year’s meeting. The PracticeUpdate
Editorial Team reports fromMiami Beach.
CDK4/6 inhibitors in hormone receptor-positive, HER2-negative
metastatic breast cancer
CDK4/6 inhibitors should be offered as first-line treatment for ER+, HER2-negative breast cancer patients since they
significantly increase the time to progression when they are combined with endocrine therapy.
T
his was the conclusion of a talk on CDK 4/6 inhibitors in ER+
HER2-negative metastatic breast cancer at the 34th Miami
Breast Cancer Conference.
Kimberly L. Blackwell, MD of Duke University Medical Center,
Durham, North Carolina explained that CDK4/6 inhibitors com-
bined with endocrine therapy have shown improvements in
progression free survival.
Dr Blackwell began by reviewing the mechanism of action of
CDK4/6 inhibitors and their interaction with cyclin D1 to phos-
phorylate the retinoblastoma tumor suppressor gene.
Dr Blackwell referred to the clinical trials that led to the FDA
approval of palbociclib for patients with ER+ metastatic breast
cancer.
PALOMA-1 is the phase II pivotal trial of palbociclib in combina-
tion with letrozole in first-line treatment of ER+ metastatic breast
cancer that showed a 10-month improvement with the combina-
tion. The confirmatory PALOMA-2 trial was a phase 3 randomized
study that enrolled 666 postmenopausal patients with ER+ meta-
static breast cancer and no prior treatment for advanced disease
to received either palbociclib in combination with letrozole or
placebo in combination with letrozole. This trial showed that the
palbociclib-letrozole group had a 10.3-month improvement in pro-
gression free survival compared to the placebo-letrozole group
with a hazard ratio of 0.58 that was statistical significant. Finally,
PALOMA-3 compared fulvestrant plus palbociclib versus fulves-
trant plus placebo in patients with hormone receptor positive
metastatic breast cancer that progressed on previous endocrine
therapy. The combination doubled progression free survival.
Ribociclib is the other CDK4/6 inhibitor that has shown to
improve progression free survival in combination with letrozole.
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