Abstract 321P
Background
CDK4/6 inhibitor (CDK4/6i) with endocrine therapy is a recommended treatment option for many patients (pts) with hormone receptor-positive, human epidermal growth factor receptor-2 negative (HR+/HER2-) locally advanced or metastatic breast cancer (aBC) in Europe. However, disease characteristics are diverse among pts treated in real-world practice, which may lead to variations in treatment. This study assessed contemporary first line (1L) treatment patterns in pts with HR+/HER2- aBC and variations across subgroups.
Methods
Oncologists in France, Germany, Italy, and Spain abstracted historical data from medical records of pts aged ≥18 years who received 1L treatment for HR+/HER2- aBC between 10/2019 and 02/2020. Demographics, clinical characteristics, and 1L treatments were described overall and within subgroups defined by age, type of metastases, and disease state at aBC diagnosis (recurrent or de novo aBC).
Results
Of the 906 pts, 99% were women; mean age at aBC diagnosis was 62 years. At abstraction, 15% had locally advanced disease and 85% had metastatic disease. Of those with metastatic disease, 49% had visceral metastasis, 32% had bone-only disease, and the remaining had other non-visceral or unknown sites of metastasis. Overall, 65% had de novo aBC and 35% had recurrent abC. Among those with recurrent aBC, 44% received prior chemotherapy (CT). Overall, 57% of pts received 1L CDK4/6i of which 74% were in combination with an aromatase inhibitor (AI) (Table). AI monotherapy was used more frequently in older pts, bone-only disease, and de novo disease. A larger proportion of pts with recurrent disease received CDK4/6i + fulvestrant (F) than those with de novo disease.
Table: 321P
1L Treatment in HR+/HER2- aBC
| 1L Treatment type (%) | All patients (n=906) | Subgroup | |||||
| Age <65 (n=488) | Age ≥65 (n=390) | Visceral metastasisa (n=347) | Bone-Only metastasis (n=245) | Recurrent diseaseb (n=313) | De Novo diseasec (n=590) | ||
| Any CDK4/6i regimen | 57 | 55 | 60 | 66 | 62 | 60 | 54 |
| CDK4/6i + AI | 74 | 70 | 78 | 67 | 76 | 57 | 84 |
| CDK4/6i + F | 24 | 27 | 22 | 30 | 22 | 41 | 14 |
| Other CDK4/6i regimen | 2 | 3 | 0 | 3 | 1 | 2 | 2 |
| AI monotherapy | 11 | 5 | 20 | 3 | 20 | 5 | 15 |
| F monotherapy | 3 | 1 | 5 | 1 | 6 | 2 | 3 |
| Chemotherapy | 13 | 17 | 6 | 13 | 4 | 14 | 13 |
| Other | 16 | 23 | 9 | 17 | 8 | 18 | 15 |
a Metastasis in ≥1 of the following sites: liver, lung, malignant effusion, adrenal, stomach, and peritoneum. b Initially diagnosed with stage 0, I, II, or IIIA breast cancer. c Initially diagnosed with stage IIIB, IIIC, or IV breast cancer.
Conclusions
Most patients with HR+/HER2- aBC received CDK4/6i with AI or F, consistent with national guidelines. Further exploration into drivers and associated outcomes of 1L endocrine monotherapy and CT is necessary to understand whether current treatment strategies could be further optimized.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Pfizer Inc.
Funding
Pfizer Inc.
Disclosure
K. Lewis: Full/Part-time employment, Employee of Adelphi Real World, who were paid consultants to Pfizer in connection with the development of this abstract.: Adelphi Real World. S. Kurosky: Shareholder/Stockholder/Stock options, Full/Part-time employment: Pfizer Inc. M. Last: Full/Part-time employment, Employee of Adelphi Real World, who were paid consultants to Pfizer in connection with the development of this abstract.: Adelphi Real World. D. Mitra: Shareholder/Stockholder/Stock options, Full/Part-time employment: Pfizer Inc. A. Lambert: Full/Part-time employment, Employee of Adelphi Real World, who were paid consultants to Pfizer in connection with the development of this abstract: Adelphi Real World. R. Mahtani: Advisory/Consultancy, Research grant/Funding (institution): Genentech; Advisory/Consultancy: Pfizer; Advisory/Consultancy: Eli Lilly; Advisory/Consultancy: Novartis; Advisory/Consultancy: Daiichi Sankyo; Advisory/Consultancy: Seattle Genetics; Advisory/Consultancy: Eisai; Advisory/Consultancy: AstraZeneca; Advisory/Consultancy: Puma; Advisory/Consultancy: Amgen.