PALOMA-2
Trial question
What is the role of palbociclib and letrozole in patients with previously untreated ER+/HER2- advanced breast cancer?
Study design
Multi-center
Double blinded
RCT
Population
666 female patients.
Inclusion criteria: patients with previously untreated ER+/HER2- advanced breast cancer.
Key exclusion criteria: confirmed diagnosis of HER2+ disease; advanced, symptomatic, visceral spread at risk of life-threatening complication; uncontrolled or symptomatic CNS metastases; prior treatment with any CDK4/6 inhibitor therapy.
Interventions
N=444 palbociclib plus letrozole (palbociclib 125 mg PO daily for 3 weeks, followed by 1 week off, plus letrozole 2.5 mg PO daily).
N=222 placebo plus letrozole (matching placebo PO for 3 weeks followed by 1 week off plus letrozole 2.5 mg PO daily).
Primary outcome
Median progression-free survival
24.8 months
14.5 months
24.8 months
18.6 months
12.4 months
6.2 months
0.0 months
Palbociclib plus
letrozole
Placebo plus
letrozole
Significant
increase ▲
Significant increase in median progression-free survival (24.8 months vs. 14.5 months; HR 1.72, 95% CI 1.39 to 2.17).
Secondary outcomes
No significant difference in objective response (42.1% vs. 34.7%; OR 1.4, 95% CI 0.98 to 2.01).
Significant increase in clinical benefit response (84.9% vs. 70.3%; OR 2.39, 95% CI 1.58 to 3.59).
Safety outcomes
No significant difference in fatigue.
Significant differences in grade 3 or 4 neutropenia (66.4% vs. 1.4%), leukopenia (24.8% vs. 0%).
Conclusion
In patients with previously untreated ER+/HER2- advanced breast cancer, palbociclib plus letrozole was superior to placebo plus letrozole with respect to median progression-free survival.
Reference
Richard S Finn, Miguel Martin, Hope S Rugo et al. Palbociclib and Letrozole in Advanced Breast Cancer. N Engl J Med. 2016 Nov 17;375(20):1925-1936.
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