Fulvestrant plus palbociclib in advanced or metastatic hormone receptor-positive/human epidermal growth factor receptor 2-negative breast cancer after fulvestrant monotherapy: Japan Breast Cancer Research Group-M07 (FUTURE trial)

• DOI: 10.1007/s10549-023-06911-5
• Publication Date: 2023-04-04T11:41:54Z
• Authors: Kenichi Watanabe; Naoki Niikura; Yuichiro Kikawa; Mari Oba; Kokoro Kobayashi; Hiroshi Tada; Shinji Ozaki; Uhi Toh; Yutaka Yamamoto; Michiko Tsuneizumi; Toshitaka Okuno; Nobutaka Iwakuma; Takashi Takeshita; Takayuki Iwamoto; Hiroshi Ishiguro; Norikazu Masuda; Shigehira Saji
• Keywords: Fulvestrant; Palbociclib; Combination therapy

The combination of cyclin-dependent kinase 4/6 inhibitors and endocrine therapy is a standard treatment for hormone receptor (HR)-positive/human epidermal growth factor 2 (HER2)-negative metastatic breast cancer (MBC); however, their toxicities financial burden are major issues, especially prolonged treatment. We investigated fulvestrant plus palbociclib in patients with HR-positive MBC resistant to monotherapy.Patients who initially received as first- or second-line were assigned group A. Patients disease progression during monotherapy subsequently B. primary endpoint was progression-free survival (PFS1) set the threshold median PFS 5 months (null hypothesis).Between January 2018 February 2020 we enrolled 167 A (January 2018-February 2020) from 55 institutions, whom 72 follow-up 23.8 8.9 groups B, respectively. B (combination therapy) 9.4 (90% confidence interval [CI]: 6.9-11.2) (p < 0.001). This 25.7 CI: 21.2-30.3) (fulvestrant monotherapy). TTF 7.2 5.5-10.4) months. In post-hoc analysis, PFS1 among longer-duration (> 1 year) longer than that shorter-duration (≤ (11.3 vs. 7.6 months). No new observed.Our findings suggest after despite potentially safe effective HR-positive/HER2-negative advanced MBC.