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William J. Gradishar, MD, FACP, FASCO
William J. Gradishar, MD, FACP, FASCO
Posted: Friday, June 10, 2022
The phase III PALOMA-2 study, conducted by Richard S. Finn, MD, of the David Geffen School of Medicine at the University of California, Los Angeles, and colleagues evaluated the use of palbociclib plus letrozole in patients with estrogen receptor (ER)-positive/HER2-negative breast cancer. During the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract LBA1003), these investigators presented their updated overall survival results.
“PALOMA-2 met its primary endpoint of improving progression-free survival, but not the secondary endpoint of overall survival,” concluded the investigators. “Patients receiving palbociclib plus letrozole had numerically longer overall survival compared to placebo plus letrozole, but the results were not statistically significant.”
The study authors focused on 666 postmenopausal women with ER-positive/HER2-negative advanced breast cancer who did not receive prior systemic therapy. Participants were randomly assigned 2:1 to receive either palbociclib plus letrozole or placebo plus letrozole. The final overall survival analysis was performed when 390 overall survival events occurred.
A total of 43 and 5 patients remained on palbociclib and placebo at data cutoff, respectively. The median overall survival with palbociclib plus letrozole was 53.9 months and was 51.2 months with placebo plus letrozole; there were 405 deaths. When excluding 21% of individuals treated with palbociclib and 13% given placebo who were not available for follow-up, median overall survivals were adjusted to 51.6 and 44.6 months, respectively.
Most individuals in both the palbociclib-plus-letrozole (81%) and placebo-plus-letrozole (88%) arms who discontinued treatment underwent poststudy systemic therapy. Among patients demonstrating a disease-free interval of more than 12 months, the median overall survival was 66.3 months and 47.4 months in the palbociclib and placebo arms, respectively. Of note, no new safety signals were reported.
Disclosure: For full disclosures of the study authors, visit coi.asco.org.
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