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Observational Study
. 2025 Jul;32(4):705-715.
doi: 10.1007/s12282-025-01689-4. Epub 2025 Apr 5.

Overall survival of palbociclib plus endocrine therapy in Japanese patients with HR+/HER2- advanced breast cancer in the first-or second-line setting: a multicenter observational study (P-BRIDGE study)

Shigenori E Nagai  1 , Masaya Hattori  2 , Tetsuhiro Yoshinami  3 , Hiroko Masuda  4 , Takuho Okamura  5 , Kenichi Watanabe  6 , Takahiro Nakayama  7 , Michiko Tsuneizumi  8 , Daisuke Takabatake  9 , Michiko Harao  10 , Hiroshi Yoshino  11 , Natsuko Mori  12 , Hiroyuki Yasojima  13 , Chiya Oshiro  14 , Madoka Iwase  15 , Miki Yamaguchi  16 , Takafumi Sangai  17 , Shinsuke Sasada  18 , Takanori Ishida  19 , Manabu Futamura  20 , Yasuaki Muramatsu  21 , Nobuyoshi Kosaka  21 , Norikazu Masuda  22
Affiliations
Observational Study

Overall survival of palbociclib plus endocrine therapy in Japanese patients with HR+/HER2- advanced breast cancer in the first-or second-line setting: a multicenter observational study (P-BRIDGE study)

Shigenori E Nagai et al. Breast Cancer. 2025 Jul.

Abstract

Background: Recently, we reported the real-world effectiveness of palbociclib plus endocrine therapy (ET) in HR+/HER2- advanced breast cancer (ABC) in Japan (NCT05399329). However, median overall survival (OS) was not reached because of limited follow-up (36 months). Here, we present follow-up data from this study, including real-world clinical outcomes and treatment patterns.

Methods: The P-BRIDGE study was a multi-center, observational study evaluating the real-world effectiveness and treatment patterns of patients diagnosed with HR+/HER2- ABC who received palbociclib plus ET in first (1L) or second line (2L) in Japan. The primary endpoint was real-world progression-free survival (rwPFS); secondary endpoints included OS and chemotherapy-free survival (CFS).

Results: Of the 693 eligible patients, 426 and 267 patients received palbociclib with ET as 1L and 2L treatment, respectively. After a median follow-up of 48.1 months, the median rwPFS (95% CI) was 26.2 months (21.4-30.4) for 1L and 14.9 months (11.7-18.3) for 2L, respectively. Median OS (95% CI) was 68.2 months (60.8-NE) for 1L and 50.7 months (42.2-57.2) for 2L, respectively. OS analysis was also performed in the following subgroups: TFI < 12 months/TFI ≥ 12months/de novo metastatic median OS was 56.3 months (43.9-68.2), NR (NE-NE), NR (56.3-NE), visceral metastasis was 65.0 months (56.3-NE), liver metastasis was 46.4 months (37.2-NE), and bone only metastasis was NR (57.8-NE) in 1L, respectively.

Conclusions: The updated results from this study further confirm the real-world effectiveness of palbociclib plus ET in routine clinical practice in Japan. More than 5 years of median OS in 1L was observed, supporting the use of palbociclib plus ET as 1L standard of care for HR+/HER2- ABC.

Keywords: Advanced breast cancer; CDK4/6 inhibitors; Japanese patients; Overall survival; Palbociclib; Real-world evidence.

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Conflict of interest statement

Declarations. Conflict of interest: SN reports honoraria from AstraZeneca, Daiichi-Sankyo, Eisai, Eli Lilly, MSD, Taiho, Chugai, and Pfizer. MaHa reports honoraria from Eli Lilly and Pfizer.TY reports honoraria from AstraZeneca, Chugai, Eisai, Eli Lilly, MSD, and Pfizer. HiMa reports honoraria from Eli Lilly, Chugai, and Pfizer. KW reports honoraria from AstraZeneca, Daiichi-Sankyo, Eisai, Shionogi, Kyowa-Kirin, Nippon-Kayaku, Novartis, Eli Lilly, Taiho, Chugai, and Pfizer. TN reports honoraria from AstraZeneca, Daiichi-Sankyo, Eisai, Novartis, Eli Lilly, Taiho, Chugai, and Pfizer. TS reports honoraria from Chugai, Novartis, MSD, Taiho, Eisai, Maruho, PDRadiopahrma, Nippon-Kayaku, Kyowa-Kirin, AstraZeneca, Eli Lilly, Daiichi -Sankyo and Pfizer; and institutional support from Taiho. MY reports honoraria from AstraZeneca, Daiichi-Sankyo, Eisai, Kyowa-Kirin, Nippon-Kayaku, Eli Lilly, Taiho, Chugai, and Pfizer. TI reports honoraria from Chugai, and Pfizer. MF reports honoraria from Chugai, Taiho, Eisai, Nippon-Kayaku, Eli Lilly, and Daiichi -Sankyo. NK is employees of Pfizer Inc. is stockholders in Pfizer Inc. YM is employees of Pfizer Inc. is stockholders in Pfizer Inc. NM reports honoraria from Chugai, Pfizer, AstraZeneca, Eli Lilly, and Daiichi -Sankyo; and institutional support from Chugai, Eli Lilly, AstraZeneca, Pfizer, Daiichi-Sankyo, MSD, Eisai, Novartis, Sanofi, KyowaKirin, and Nippon Kayaku. TO, MT, DT, MiHa, HY, NaMo, HY, CO, MI, and SS have no disclosures.

Figures

Fig. 1
Fig. 1
Patient flow diagram
Fig. 2
Fig. 2
A Real-world PFS B OS and C CFS of palbociclib plus ET as 1L and 2L treatment. PFS progression-free survival, OS overall survival, CFS chemotherapy-free survival, ET endocrine therapy
Fig. 3
Fig. 3
Analysis for rwPFS and OS of palbociclib plus ET as 1L and 2L treatment in subgroup. rwPFS (A) and OS (B) in the patients of absence or presence of visceral metastasis. rwPFS (C) and OS (D) in the patients of absence or presence of liver metastasis. OS (E) in the patients with bone only metastasis. OS (F) in patients with TFI ≥ 12 months, TFI < 12 months, and de novo metastatic disease. PFS progression-free survival, OS overall survival, ET endocrine therapy, TFI treatment-free interval
See this image and copyright information in PMC

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