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. 2022 Oct 11;8(1):114.
doi: 10.1038/s41523-022-00479-x.

Real-world study of overall survival with palbociclib plus aromatase inhibitor in HR+/HER2- metastatic breast cancer

Hope S Rugo  1 , Adam Brufsky  2 , Xianchen Liu  3 , Benjamin Li  3 , Lynn McRoy  3 , Connie Chen  3 , Rachel M Layman  4 , Massimo Cristofanilli  5 , Mylin A Torres  6 , Giuseppe Curigliano  7 , Richard S Finn  8 , Angela DeMichele  9
Affiliations

Real-world study of overall survival with palbociclib plus aromatase inhibitor in HR+/HER2- metastatic breast cancer

Hope S Rugo et al. NPJ Breast Cancer. .

Abstract

Data on real-world effectiveness of cyclin-dependent kinase 4/6 inhibitor combination therapy versus endocrine therapy alone are limited. The Flatiron Health Analytic Database was used to assess overall survival (OS) in patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer (MBC) treated with first-line palbociclib plus an aromatase inhibitor (AI) versus an AI alone in routine US clinical practice. In total, 2888 patients initiated treatment during February 3, 2015-March 31, 2020, with a potential ≥6-month follow-up (cutoff date, September 30, 2020). After stabilized inverse probability treatment weighting, median OS (95% CI) is significantly longer among palbociclib versus AI recipients (49.1 [45.2-57.7] versus 43.2 [37.6-48.0] months; hazard ratio, 0.76 [95% CI, 0.65-0.87]; P < 0.0001). Progression-free survival (95% CI) is 19.3 (17.5-20.7) versus 13.9 (12.5-15.2) months, respectively (hazard ratio, 0.70 [95% CI, 0.62-0.78]; P < 0.0001). These data support first-line palbociclib plus an AI treatment for HR+/HER2- MBC.(Trial number NCT05361655).

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Conflict of interest statement

The authors declare no competing non-financial interests but the following competing financial interests: H.S.R. reports sponsored research to her institution from Pfizer Inc, Merck, Novartis, Eli Lilly, Roche, Daiichi-Sankyo, Seattle Genetics, Macrogenics, Sermonix, Boehringer Ingelheim, Polyphor, AstraZeneca, Ayala, and Gilead and honoraria from PUMA, Samsung, and Mylan. A.B. reports advisory/consultancy fees from Pfizer Inc. R.M.L. reports advisory/consultancy fees from Novartis, Eli Lilly, and Celcuity and research/grant funding from Pfizer Inc, Novartis, Eli Lilly, GlaxoSmithKline, Zentalis, Puma, and Celcuity. M.C. reports advisory/consultancy fees (Data Safety Monitoring Board or Advisory Board) from Merck and AstraZeneca; research grant/funding from Pfizer Inc, Menarini, Eli Lilly, and G1 Therapeutics; consulting fees from Novartis, Menarini, Eli Lilly, Sermonix, G1 Therapeutics, AstraZeneca, Pfizer Inc, and Foundation Medicine; and travel support from Foundation Medicine. M.A.T. reports research grant/funding from Pfizer Inc and Genentech, advisory/consulting fees from Centers for Disease Control and Oncohealth, and honoraria from MJH Life Sciences. G.C. reports consulting fees from Seagen, Roche, Novartis, Lilly, Daiichi Sankyo, Astra Zeneca, Pfizer, Sanofi, Pierre Fabre, and Gilead and fees for non-CME services (eg, speakers’ bureaus) from Lilly, Pfizer, and Daiichi Sankyo. R.S.F. reports consulting fees/honoraria from Pfizer Inc and research grant/funding from Pfizer Inc, Eli Lilly, and Novartis. A.D. reports research grant/funding from Pfizer Inc, Novartis, Calithera, and Genentech. X.L., B.L., L.M., and C.C. are employees of and stockholders in Pfizer Inc.

Figures

Fig. 1
Fig. 1. Patient attrition diagram.
ER+  estrogen receptor–positive; HER2−  human epidermal growth factor receptor 2–negative; HR+  hormone receptor–positive; ICD9/10 International Classification of Diseases, 9th/10th Revision; MBC  metastatic breast cancer; PR+  progesterone receptor–positive. *Confirmed HR+/HER2− status: HR+ is defined as any ER+ or PR+ biomarker test before or up to 60 days after metastatic diagnosis; HER2− is defined as any HER2− test and the absence of a positive test before or up to 60 days after metastatic diagnosis. †Lines were selected regardless of whether they contained a luteinizing hormone–releasing hormone agonist (leuprolide, goserelin, and triptorelin).
Fig. 2
Fig. 2. Kaplan–Meier curves of overall survival.
AI aromatase inhibitor; NE not estimable; OS overall survival; PAL palbociclib; PSM propensity score matching; sIPTW stabilized inverse probability of treatment weighting. Statistical significance was analyzed by a weighted Cox proportional hazards model.
Fig. 3
Fig. 3. Forest plot of overall survival by subgroup after sIPTW.
AI aromatase inhibitor; Dx diagnosis; ECOG PS Eastern Cooperative Oncology Group performance status; ND not documented; PAL palbociclib; sIPTW stabilized inverse probability of treatment weighting. *Bone-only disease was defined as metastatic disease in the bone only. †Visceral disease was defined as metastatic disease in the lung and/or liver; patients could have had other sites of metastases. No visceral disease was defined as no lung or liver metastases.
Fig. 4
Fig. 4. Forest plot of overall survival by subgroup after PSM.
AI aromatase inhibitor; Dx diagnosis; ECOG PS Eastern Cooperative Oncology Group performance status; ND not documented; PAL palbociclib; PSM propensity score matching. *Bone-only disease was defined as metastatic disease in the bone only. †Visceral disease was defined as metastatic disease in the lung and/or liver; patients could have had other sites of metastases. No visceral disease was defined as no lung or liver metastases.
Fig. 5
Fig. 5. Kaplan–Meier curves of real-world progression-free survival.
AI aromatase inhibitor; PAL palbociclib; PSM propensity score matching; rwPFS real-world progression-free survival; sIPTW stabilized inverse probability of treatment weighting. Statistical significance was analyzed by a weighted Cox proportional hazards model.
Fig. 6
Fig. 6. Forest plot of real-world progression-free survival by subgroup after sIPTW.
AI aromatase inhibitor; Dx diagnosis; ECOG PS Eastern Cooperative Oncology Group performance status; ND not documented; PAL palbociclib; sIPTW=stabilized inverse probability of treatment weighting. *Bone-only disease was defined as metastatic disease in the bone only. †Visceral disease was defined as metastatic disease in the lung and/or liver; patients could have had other sites of metastases. No visceral disease was defined as no lung or liver metastases.
Fig. 7
Fig. 7. Forest plot of real-world progression-free survival by subgroup after PSM.
AI aromatase inhibitor; Dx diagnosis; ECOG PS Eastern Cooperative Oncology Group performance status; ND not documented; PAL palbociclib; PSM propensity score matching. *Bone-only disease was defined as metastatic disease in the bone only. †Visceral disease was defined as metastatic disease in the lung and/or liver; patients could have had other sites of metastases. No visceral disease was defined as no lung or liver metastases.
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