Endocrine therapy and cyclin-dependent kinase (CDK) 4/6 inhibitors (CDK4/6i) are standard treatment options for hormone receptor positive (HR+)/human epidermal growth factor receptor 2 negative (HER2–) metastatic breast cancer (MBC). However, the efficacy of standard subsequent therapies after CDK4/6i-based treatment is unclear. This study aimed to examine physician practice patterns and treatment outcomes of subsequent therapies administered after progression on palbociclib therapy in clinical practice. The study included 200 patients with HR+/HER2– MBC who underwent subsequent treatments after progressing on palbociclib-based regimens in five Chinese institutions between August 2017 and April 2020. The treatment pattern, progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) were reported. A total of 200 patients were included, of whom 147 (73.5%) and 53 (26.5%) received subsequent chemotherapy and endocrine therapy, respectively. The frequently used monochemotherapy regimens were taxane (n = 29), capecitabine (n = 21), and vinorelbine (n = 17), while the endocrine therapy regimens were chidamide plus exemestane (n = 16) and everolimus plus exemestane (n = 9). The overall median PFS (mPFS) was 5.5 months, with no significant difference in mPFS between the chemotherapy and endocrine therapy groups (p = 0.669). However, among patients not sensitive to prior palbociclib treatment, those administered chemotherapy had significantly longer PFS than those administered endocrine therapy (p = 0.006). The mPFS with endocrine therapy after first-, second-, and subsequent-line palbociclib was 13.4, 3.1, and 4.1 months, respectively (p = 0.233); in contrast, the mPFS with chemotherapy was 7.2, 6.5, and 4.9 months after first-, second-, and subsequent-line palbociclib, respectively (p = 0.364). The median OS was not achieved. The ORR was 10.6% among the 198 patients included in the analysis. Physicians prefer chemotherapy over endocrine therapy for the treatment of patients with HR+/HER2– MBC who develop progression on palbociclib. Sensitivity to previous palbociclib treatment might be one of the indicators for predicting response to subsequent treatment. ClinicalTrials.gov identifier: NCT04517318

Introduction: Pyrotinib plus capecitabine has been approved in China for human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC). Meanwhile, vinorelbine is another important chemotherapy option for MBC available in oral and intravenous forms. Thus, pyrotinib plus vinorelbine may represent a new treatment option, particularly for patients with failed capecitabine treatment. This study reported the first real-world data for pyrotinib plus vinorelbine therapy in HER2+ MBC.Methods: HER2+ MBC patients (n = 97) treated with pyrotinib plus vinorelbine in six institutions across China from May 2018 to June 2020 were enrolled. Progression-free survival (PFS), objective response rate (ORR), overall survival (OS), and toxicity profiles were determined.Results: Sixty-seven percent of patients received more than two lines of systematic therapy. Nearly all patients (97.9%) had received trastuzumab and 50.5% were administered lapatinib. When combined with pyrotinib, 74.2% received oral and 25.8% received intravenous vinorelbine. Median PFS (mPFS) was 7.8 (range, 4.7–10.8) months for all patients. The mPFS in patients administered pyrotinib as second-line therapy and third-or-higher-line therapy were 12.0 and 6.4 months, respectively. Patients who received pyrotinib plus oral or intravenous vinorelbine had similar mPFS (7.8 vs. 6.4 months, p = 0.871). The 23 patients with brain metastases had mPFS of 6.3 (range, 3.4–9.2) months. Lapatinib-naïve patients had significantly longer PFS than lapatinib-treated patients (10.8 months vs. 5.6 months, p = 0.020). Median OS was not achieved. The ORR for 96 patients was 34.3%. Common grade 3 and 4 adverse events were diarrhea (22.7%), neutropenia (7.2%), and leukopenia (4.1%).Conclusions: Pyrotinib plus vinorelbine therapy demonstrated promising effects in HER2+ MBC with tolerable toxicity, particularly in patients with second-line treatment and without prior lapatinib treatment, as well as in patients with brain metastases. Oral vinorelbine is a useful alternative to the intravenous form when combined with pyrotinib.Clinical Trial Registration: [ClinicalTrials.gov], identifier [NCT04517305].

The clinical value of ¹⁸F-fluoroestradiol in assisting individualized treatment decision in dual primary malignancies Ziyi Yang, Yizhao Xie, Cheng Liu, Xin Liu, Shaoli Song, Yingjian Zhang, Rui Ge, Biyun Wang, Zhongyi Yang

Introduction: Combination of trastuzumab (T) and lapatinib (L) has been showed to significantly improve the prognosis of HER2+ heavily pretreated metastatic breast cancer (MBC). Whether TL combined chemotherapy (TLC) can further improve the efficacy in HER2+ MBC remains to be further studied. The aim of the study was to report the first real-world data of TLC in HER2+ MBC, including the efficacy, safety and treatment patterns. Methods: Patients with HER2+ MBC treated with TLC in 5 institutions of China from September 2013 to July 2019 were included. Progression free survival (PFS), objective response rate (ORR), overall survival (OS), toxicity profile and treatment pattern were reported. Results: A total of 285 patients were included. 88.8% were exposed to trastuzumab and 49.2% received 2 or more lines of systematic therapy before TLC previously. The most common chemotherapy regimens combined with TL were capecitabine (40.7%) and vinorelbine (21.4%) and almost 1/3 received maintenance treatment after TLC. Median PFS was 10.9 months while patients received TLC as first line treatment showed longest median PFS of 20.7 months. Patients pretreated with trastuzumab showed a median PFS of 10.2 months. In patients who pretreated with trastuzumab, the continuation of trastuzumab on the basis of standard lapatinib plus capecitabine had a median PFS of 11.3 months. TL combined with capecitabine or vinorelbine showed no significant difference in median PFS, though TL combined with capecitabine had numerically prolongation (11.4 vs. 8.5 months, p = 0.231). Patients had brain metastasis (BM) also showed a median PFS (intracranial and extracranial lesions considered) of 10.6 months. Lines of systematic metastatic treatment was an independent predictive factor of PFS. The median OS was not reached. Two hundred and seventy seven patients were included in ORR analysis. ORR was 42.6%. Toxicities of triplet combinations were tolerable and the most common grade 3 and 4 adverse events were neutropenia (16.8%). Conclusions: TLC demonstrated promising effects and tolerable safety in HER2+MBC, even in patients with BM, providing a theoretical basis for clinical practice. Clinical Trial Registration: ClinicalTrials.gov, Identifier: NCT04001634.

Background: Eribulin is a nontaxane microtubule inhibitor approved in China for patients with advanced breast cancer who show progression after ⩾2 lines of chemotherapy. The aim of this study was to determine the efficacy and safety profile of eribulin and explore potential predictive factors for the efficacy of eribulin among Chinese women with metastatic breast cancer (MBC) in real-world practice. Patients and Methods: A total of 272 consecutive MBC patients who were treated with eribulin between November 2019 and October 2020 in 9 institutions nationwide were included in this study. Eribulin was administered intravenously at a dose of 1.4 mg/m² on days 1 and 8 of a 21-day cycle. Efficacy outcomes included progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and clinical benefit rate (CBR). Adverse events (AEs) were graded according to The National Cancer Institute Common Toxicity Criteria (NCI-CTC) version 5.0. Results: Eribulin showed a median PFS of 4.1 months (95% confidence interval [CI] 3.6–4.6); however, the OS data were immature. The ORR was 17.6% and the CBR was 24.6%. A total of 51.8% of patients received eribulin monotherapy, while 48.2% of patients were treated with eribulin plus targeted therapy or other chemotherapy. The number of metastatic sites, duration of previous taxane treatment for MBC, and combination with bevacizumab were significant in Cox multivariate analysis ( p = 0.023, p = 0.048, and p = 0.046, respectively) and were significantly associated with PFS of eribulin. The most common AEs with eribulin treatment were hematological toxicities, including neutropenia, leukopenia, and anemia. Conclusion: Eribulin was effective with a manageable toxicity profile in clinical practice. Furthermore, when prescribed in combination with other agents, eribulin did not increase the toxic effects of each agent. Eribulin monotherapy or plus other agents is an alternative for the heavily pretreated patients with MBC.

Background: Pyrotinib is a newly-developed irreversible pan-ErbB (erythroblastic leukemia viral oncogene homolog) receptor oral tyrosine kinase inhibitor (TKI) with promising efficacy in the human epidermal growth factor receptor-2 (HER2) positive breast cancer. The phase III PHOEBE study proved that pyrotinib plus capecitabine exceeded lapatinib plus capecitabine (LX) in PFS (p < 0.001). Oral vinorelbine is commonly used in combination with anti-HER2 treatment. However, no evidence was reported in terms of the real-world pattern, safety, and efficacy of pyrotinib plus vinorelbine (NP) compared with LX.Methods: Medical records were retrospectively evaluated for all HER2-positive metastatic breast cancer (MBC) patients who experienced progression on prior trastuzumab-containing regimens (advanced setting) and taxane (any setting) and received NP or LX therapy from 2015 to 2021 in five institutions.Results: A total of 224 patients were enrolled and evaluated, of which 132 (58.9%) patients received LX and 92 (41.1%) patients received NP. The median progression-free survival (mPFS) of NP group was significantly longer than that in LX group (8.3 vs 5.0 months, HR = 0.47 95% CI 0.34–0.65, p < 0.001). The advantage of NP over LX was seen both in patients with trastuzumab resistance (p < 0.001) and refractoriness (p = 0.004). The NP group had more diarrhea cases (23.9%) compared to the LX group (8.3%). Discontinuation rates in the two groups were similar.Conclusions: This trial revealed the clinical practice of NP and LX treatment among HER2+ MBC patients pretreated with trastuzumab in China. More patients received LX than NP in real-world while the efficacy of NP exceeded LX in terms of PFS regardless of resistant status of trastuzumab. Although the NP group had more diarrhea cases, toxicities in both groups were acceptable.