Search

Background: CDK4/6 inhibitors (CDK4/6i) have shown promising results in the treatment of hormone receptor‐positive (HR+) metastatic breast cancer (MBC) when combined with endocrine therapy (ET). It is crucial to evaluate the actual effectiveness and safety of CDK4/6i in clinical practice, as well as to analyze the factors that can predict their outcomes. Methods: Patients with HR+ MBC who received CDK4/6i‐based therapy between May 2016 and May 2023 at Hunan Cancer Hospital were evaluated for progression‐free survival (PFS). Adverse reactions were assessed based on the National Cancer Institute Common Toxicity Criteria (version 5.0). Results: This study included 344 patients, with a median PFS (mPFS) of 12.8 months (range: 10.4–15.2 months). After adjustment, Cox multivariate regression analysis revealed that visceral metastasis (specifically liver and brain metastases), Eastern Cooperative Oncology Group Performance Status (ECOG PS) ≥ 1, estrogen receptor ≤ 80%, progesterone receptor ≤ 10%, Ki‐67 > 30%, and treatment in later stages were significant factors associated with reduced PFS. Based on this, we created a prognostic nomogram and validated its performance, obtaining a C‐index of 0.714 (95% confidence interval: 0.640–0.787) as well as reliable calibration and clinical impact. The mPFS of CDK4/6i rechallenge was 7.7 months; for patients who initially discontinued CDK4/6i for reasons other than disease progression, CDK4/6i rechallenge still provided a mPFS of 11.4 months. The tolerability and safety of combining CDK4/6is with ET were manageable. Adverse events led to treatment discontinuation in 3.8% of patients. Neutropenia (29.1%), leukopenia (13.7%), and anemia (4.1%) were the primary grade 3/4 adverse reactions. Conclusions: This real‐world study highlights the ample efficacy and reasonable safety of combined CDK4/6i and ET in patients with HR+ MBC. Individualized treatment decisions and ongoing safety monitoring are important to optimize the therapeutic benefit of CDK4/6i treatment. [ABSTRACT FROM AUTHOR]

Background: Approximately 40% of patients with hormone receptor (HR)‐positive and human epidermal growth factor receptor 2 (HER2)‐negative advanced breast cancer (ABC) exhibit PIK3CA mutations. Aims: This study aims to evaluate the safety, tolerability, pharmacokinetics, and preliminary antitumor activity of HS‐10352, a selective PI3Kα inhibitor, in this patient population. Materials and Methods: Conducted as a phase 1 dose‐escalation trial, HS‐10352 was administered orally once‐daily (QD) at dose levels of 2, 4, 6, and 8 mg. The primary endpoints were dose‐limiting toxicity (DLT) and the maximum tolerated dose (MTD). This study is registered at ClinicalTrials.gov (NCT04631835). Results: Between August 2020 and March 2022, a total of 18 female patients were enrolled. DLT, manifested as hyperglycemia, occurred in two patients in the 8 mg QD group, establishing an MTD of 6 mg QD. The most common treatment‐related adverse events were hyperglycemia (88.9%) and weight loss (61.3%). In the 6 mg QD group, four patients (66.7%) had a partial response (PR), and one (16.7%) had stable disease (SD). Among the four patients with PIK3CA mutated tumors in this dosage group, three (75.0%) had PR and one (25.0%) had SD. The median progression‐free survival was not reached (95% confidence interval, 11.1‐NA). Discussion and Conclusion: HS‐10352 at 6 mg QD was well‐tolerated in patients with HR‐positive, HER2‐negative ABC, and showed preliminary antitumor activity in patients with PIK3CA mutated tumors. These findings support the further clinical development of HS‐10352. [ABSTRACT FROM AUTHOR]

Pyrotinib, an irreversible pan‐ErbB inhibitor, has been approved for treating HER2‐positive advanced breast cancer in China. We conducted a nationwide, prospective observational study to examine the real‐world data of pyrotinib‐based therapy in this population. Patients from 61 sites across China were included. Pyrotinib‐based regimens were prescribed at local physician's discretion. Demographics, treatment patterns, prognosis and safety were evaluated. The primary outcome was real‐world progression‐free survival (rwPFS). Of 1129 patients, pyrotinib‐based therapy was prescribed as first‐, second‐ and third‐ or later‐line treatment in 437 (38.7%), 476 (42.2%) and 216 (19.1%) patients, respectively. Median rwPFS (mrwPFS) was 14.3 (95% CI, 13.3‐15.2) months in the total population, with the longest mrwPFS of 17.8 (95% CI, 15.2‐24.9) months in the first‐line setting, followed by 14.4 (95% CI, 12.9‐15.3) months in the second‐line setting. Patients with third‐ or later‐line treatment also achieved a mrwPFS of 9.3 (95% CI, 8.4‐11.8) months. Patients with trastuzumab‐ or trastuzumab‐pertuzumab‐treated disease achieved a mrwPFS of 14.3 and 13.6 months, respectively. Dual HER2 blockade with pyrotinib plus trastuzumab showed a mrwPFS of 16.2 months in the total population, with data not mature in the first‐line setting. For patients with baseline brain metastases, the mrwPFS was 11.7 months. The most common adverse event was diarrhea (any grade, 73.5%; grade ≥ 3, 15.3%). In real world, pyrotinib‐based therapy shows promising effectiveness in the first‐, as well as second‐ and later‐line treatment, with acceptable tolerability. Further investigations regarding front‐line use or novel combinations of pyrotinib might facilitate to maximize its anti‐tumor potential. [ABSTRACT FROM AUTHOR]

Background: Patients with human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer and primary resistance to trastuzumab have a poor clinical outcome and lack good evidence to inform clinical decision. This study investigated the efficacy and safety of pyrotinib plus capecitabine in this population. Methods: This phase 2 trial was conducted at 16 sites in China. Patients received oral pyrotinib 400 mg once daily and capecitabine 1000 mg/m2 twice a day on days 1–14 of each 21-day cycle until disease progression or intolerable toxicity. The primary endpoint was investigator-assessed progression-free survival (PFS). Results: Between June 2019 and September 2021, 100 patients were enrolled with a median age of 51 years (range, 24–69). All patients had been treated with trastuzumab and 21 (21.0%) patients had prior use of pertuzumab. As of August 31, 2022, the median follow-up duration was 20.1 months (range, 1.3–38.2). The median PFS was 11.8 months (95% confidence interval [CI], 8.4–15.1), which crossed the pre-specified efficacy boundary of 8.0 months. The objective response rate was 70.0% (70/100), with a median duration of response of 13.8 months (95% CI, 10.2–19.3). The disease control rate was 87.0% (87/100). The median overall survival was not reached. The most common grade ≥ 3 treatment-emergent adverse event was diarrhea (24 [24.0%]). No treatment-related deaths occurred. Conclusions: Pyrotinib plus capecitabine can be considered to be a treatment option in HER2-positive advanced breast cancer patients who have shown primary resistance to trastuzumab. Even in the era of modern anti-HER2 treatments, this clinical setting warrants more investigations to meet unmet needs. Trial registration: ClinicalTrials.gov, NCT04001621. Retrospectively registered on June 28, 2019. [ABSTRACT FROM AUTHOR]

Entinostat plus exemestane in hormone receptor-positive (HR+) advanced breast cancer (ABC) previously showed encouraging outcomes. This multicenter phase 3 trial evaluated the efficacy and safety of entinostat plus exemestane in Chinese patients with HR + ABC that relapsed/progressed after ≥1 endocrine therapy. Patients were randomized (2:1) to oral exemestane 25 mg/day plus entinostat (n = 235) or placebo (n = 119) 5 mg/week in 28-day cycles. The primary endpoint was the independent radiographic committee (IRC)-assessed progression-free survival (PFS). The median age was 52 (range, 28–75) years and 222 (62.7%) patients were postmenopausal. CDK4/6 inhibitors and fulvestrant were previously used in 23 (6.5%) and 92 (26.0%) patients, respectively. The baseline characteristics were comparable between the entinostat and placebo groups. The median PFS was 6.32 (95% CI, 5.30–9.11) and 3.72 (95% CI, 1.91–5.49) months in the entinostat and placebo groups (HR, 0.76; 95% CI, 0.58–0.98; P = 0.046), respectively. Grade ≥3 adverse events (AEs) occurred in 154 (65.5%) patients in the entinostat group versus 23 (19.3%) in the placebo group, and the most common grade ≥3 treatment-related AEs were neutropenia [103 (43.8%)], thrombocytopenia [20 (8.5%)], and leucopenia [15 (6.4%)]. Entinostat plus exemestane significantly improved PFS compared with exemestane, with generally manageable toxicities in HR + ABC (ClinicalTrials.gov #NCT03538171). In this multicenter phase III trial in Chinese patients with hormone receptor-positive advanced breast cancer, entinostat plus exemestane significantly prolonged the progression-free survival compared to placebo plus exemestane (HR = 0.76, P = 0.046). [Display omitted] [ABSTRACT FROM AUTHOR]

Circulating tumor DNA (ctDNA) has good clinical guiding value for metastatic breast cancer (MBC) patients. This study aimed to apply a novel genetic analysis approach for therapeutic prediction based on ctDNA alterations. This nonrandomized, multicenter study recruited 223 MBC patients (NCT05079074). Plasma samples were collected for target-capture deep sequencing of ctDNA at baseline, after the 2nd cycle of treatment, and when progressive disease (PD) was evaluated. Samples were categorized into four levels according to the number of ctDNA alterations: level 1 (no alterations), level 2 (1–2 alterations), level 3 (3–4 alterations) and level 4 (≥5 alterations). According to ctDNA alteration level and variant allele frequency (VAF), a novel ctDNA-level Response Evaluation Criterion in Solid Tumors (ctle-RECIST) was established to assess treatment response and predict progression-free survival (PFS). The median PFS in level 1 (6.63 months) patients was significantly longer than that in level 2–4 patients (level 2: 5.70 months; level 3–4: 4.90 months, p < 0.05). After 2 cycles of treatment, based on ctle-RECIST, the median PFS of level-based disease control rate (lev-DCR) patients was significantly longer than that of level-based PD (lev-PD) patients [HR 2.42 (1.52–3.85), p < 0.001]. In addition, we found that ctDNA level assessment could be a good supplement to radiologic assessment. The median PFS in the dual-DCR group tended to be longer than that in the single-DCR group [HR 1.41 (0.93–2.13), p = 0.107]. The ctDNA alteration level and ctle-RECIST could be novel biomarkers of prognosis and could complement radiologic assessment in MBC. • Based on the number of ctDNA alterations, samples were categorized into four levels: level 1 to level 4. • ctDNA alterations differed in different alteration level groups. • Higher ctDNA alteration levels (levels 3–4) were associated with a higher probability of liver metastasis. • According to ctDNA alteration level and variant allele frequency, a novel ctDNA-level RECIST (ctle-RECIST) was established to assess treatment response. • ctle-RECIST can not only independently predict PFS, but also assist radiologic assessment and improve the clinical application value of prediction. [ABSTRACT FROM AUTHOR]

Purpose: We used targeted capture sequencing to analyze TP53‐mutated circulating tumor DNA (ctDNA) in metastatic breast cancer patients and to determine whether TP53 mutation has predictive value for anti‐human epidermal growth factor receptor 2 (HER2) treatment for in HER2 amplification‐positive patients (HER2+) and HER2 mutation‐positive, amplification‐negative (HER2−/mut) patients. Patients and Methods: TP53 mutation features were analyzed in the Geneplus cohort (n = 1184). The MSK‐BREAST cohort was used to explore the value of TP53 mutation in predicting anti‐HER‐2 antibody efficacy. Sequencing of ctDNA in phase Ib, phase Ic, phase II clinical trials of pyrotinib (HER2+ patients), and an investigator‐initiated phase II study of pyrotinib (HER2−/mut patients) were performed to analyze the relationships between TP53 mutation and prognosis for HER2 TKIs. The MSK‐BREAST cohort, MutHER, and SUMMIT cohort were used for verification. Results: TP53 mutations were detected in 53.1% (629/1184) of patients in the Geneplus cohort. The TP53 mutation rate was higher in HR‐negative (p < 0.001) and HER2 amplification‐positive (p = 0.015) patients. Among patients receiving anti‐HER2 antibody therapy, those whose tumors carried TP53 mutations had a shorter PFS (p = 0.004). However, the value of TP53 mutation in predicting HER2 TKI response was inconsistent. In HER2+ patients, no difference in PFS was observed among patients with different TP53 statuses in the combined analysis of the pyrotinib phase Ib, phase Ic, and phase II clinical trials (p = 1.00) or in the MSK‐BREAST cohort (p = 0.62). In HER2−/mut patients, TP53 mutation‐positive patients exhibited a trend toward worse prognosis with anti‐HER2 TKI treatment than TP53‐wild‐type patients in our investigator‐initiated phase II study (p = 0.15), and this trend was confirmed in the combined analysis of the MutHER and SUMMIT cohorts (p = 0.01). Conclusions: TP53 mutation can be used to identify biomarkers of anti‐HER2 antibody drug resistance in HER2+ patients and HER2 TKI resistance in HER2−/mut patients. [ABSTRACT FROM AUTHOR]

Background: Recent data on first-line treatment patterns administered to hormone receptor-positive (HR+) advanced breast cancer (ABC) patients in the real-world setting are limited. This study aimed to report the first-line treatment patterns and outcomes of HR+ ABC patients in China. Methods: This was a multicenter, noninterventional study. Eligible patients were cytologically or histologically confirmed to have HR+ ABC with ≥2 complete medical records and received first-line therapies between January 2015 and June 2019. Treatment patterns and outcomes were extracted from structured or unstructured electronic medical records. Progression-free survival (PFS) was analyzed with the Kaplan-Meier method. Results: In total, 1072 patients with HR+ ABC were enrolled at 6 treatment sites: 327 human epidermal growth factor receptor 2-positive (HER2+) patients, 696 HER2-negative (HER2-) patients and 49 HER2-unknown patients. Overall, 62.41% of patients received first-line chemotherapy (CT), 21.08% received targeted therapy (TT) and 15.49% received endocrine therapy (ET). For HR+/HER2+ patients, 65.14% received TT, 28.44% received CT, and 5.81% received ET. Compared with patients who received TT, patients who received CT alone, had a significantly worse median PFS (adjusted hazard ratio [HR] =2.59, 95% confidence interval [CI], 1.64-4.10, p<0.001). For HR+/HER2- patients, 77.01% received CT, 20.69% received ET and 1.15% received TT. Compared with patients who received ET, patients who received CT with maintenance therapy had a significantly prolonged median PFS (adjusted HR =0.57, 95% CI, 0.44-0.76, p<0.001). Among HR+/HER2- patients who received CT with maintenance treatment, those with maintenance ET had a longer median PFS than those with maintenance CT, but the difference was not significant (adjusted HR=0.92, 95% CI, 0.64-1.33, p=0.66). Conclusions: This real-world study demonstrates that CT remains the mainstream first-line treatment option for HR+ patients in China. Among patients with HR+/HER2+ ABC, the majority received first-line TT and experienced a PFS benefit. A high percentage of HR+/HER2- patients received CT as first-line therapy in clinical practice. PFS benefit was significantly longer in patients who received CT with maintenance therapy. Moreover, there was no obvious difference in PFS between maintenance ET and CT. Maintenance ET may be a better choice considering its lower toxicity and better quality of life. [ABSTRACT FROM AUTHOR]

Background: Patients with HER2-positive metastatic breast cancer have a high risk of developing brain metastases. Efficacious treatment options are scarce. We investigated the activity and safety of pyrotinib plus capecitabine in patients with HER2-positive metastatic breast cancer and brain metastases.Methods: We did a multicentre, single-arm, two-cohort, phase 2 trial in eight tertiary hospitals in China. Patients aged 18 years or older who had radiotherapy-naive HER2-positive brain metastases (cohort A) or progressive disease after radiotherapy (cohort B), with an Eastern Cooperative Oncology Group performance status of 0-2, received pyrotinib 400 mg orally once daily, and capecitabine 1000 mg/m2 orally twice daily for 14 days, followed by 7 days off every 3 weeks until disease progression or unacceptable toxicity. The primary endpoint was confirmed intracranial objective response rate by investigator assessment according to the Response Evaluation Criteria In Solid Tumours (version 1.1). Activity and safety were analysed in patients with at least one dose of study drug. The study is ongoing, but recruitment is complete. The study is registered with ClinicalTrials.gov, NCT03691051.Findings: Between Jan 29, 2019, and July 10, 2020, we enrolled 78 women: 51 (86%) of 59 patients in cohort A and 18 (95%) of 19 patients in cohort B had previous exposure to trastuzumab. Median follow-up duration was 15·7 months (IQR 9·7-19·0). The intracranial objective response rate was 74·6% (95% CI 61·6-85·0; 44 of 59 patients) in cohort A and 42·1% (20·3-66·5; eight of 19 patients) in cohort B. The most common grade 3 or worse treatment-emergent adverse event was diarrhoea (14 [24%] in cohort A and four [21%] in cohort B). Two (3%) patients in cohort A and three (16%) in cohort B had treatment-related serious adverse events. No treatment-related deaths occurred.Interpretation: To our knowledge, this is the first prospective study showing the activity and safety of pyrotinib plus capecitabine in patients with HER2-positive breast cancer and brain metastases, especially in radiotherapy-naive population. This combination deserves further validation in a randomised, controlled trial.Funding: National Cancer Centre Climbing Foundation Key Project of China, Jiangsu Hengrui Pharmaceuticals.Translation: For the Chinese translation of the abstract see Supplementary Materials section. [ABSTRACT FROM AUTHOR]

Introduction: 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. Methods: 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. Results: 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. Conclusions: 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 [ABSTRACT FROM AUTHOR]

Breast cancer is the most common malignant tumor among women in the world. In 2005, there were approximately 272,000 new cases diagnosed and more than 70,000 deaths from breast cancer in China. Of the patients who are newly diagnosed with breast cancer each year, approximately 3% to 10% have distant metastases at the time of diagnosis. Of those who have early stage disease at diagnosis, from 30% to 40% will develop advanced breast cancer. The 5-year survival rate for patients with advanced breast cancer is only 20%, and the median overall survival (OS) is 2 to 3 years. Although advanced breast cancer is still difficult to cure, physicians can relieve clinical symptoms, improve quality of life, and further prolong survival through the development of new drugs and the optimization model of treatment. Patients with advanced breast cancer have their own preferences in the choice of treatment options. Moreover, there is no standard recommendation for the treatment of refractory breast cancer after multiline therapy. To offer a reference for clinicians, a Chinese expert group has analyzed, summarized, and discussed related research data on the diagnosis, treatment, and prognosis of inoperable, locally advanced breast cancer and recurrent or metastatic breast cancer and has developed the Chinese expert consensus on the clinical diagnosis and treatment of advanced breast carcinoma (2018). [ABSTRACT FROM AUTHOR]

Inetetamab is a novel recombinant humanized anti-HER2 monoclonal antibody. This study aimed to evaluate the efficacy and safety of inetetamab and predictive factors for response in HER2-positive metastatic breast cancer (MBC) patients. A cohort of HER2-positive MBC patients who received inetetamab-based therapy between June 2020 and August 2021 was evaluated. The primary endpoint was progression-free survival (PFS), and the secondary endpoints included objective response rate (ORR) and disease control rate (DCR). Adverse events (AEs) were graded according to the National Cancer Institute Common Toxicity Criteria. A total of 141 patients were included in the final analysis. The median PFS of the entire cohort was 7.1 months. The median number of treatment lines administered was three. The ORR was 36.9 %, and the DCR was 80.9 %. The most frequently employed treatment strategy was inetetamab + chemotherapy (49/141, 34.8 %), followed by inetetamab + HER2-tyrosine kinase inhibitors (HER2-TKIs) + chemotherapy, inetetamab + pertuzumab + chemotherapy, inetetamab + endocrine treatment and inetetamab + HER2-TKIs. Cox multivariate analysis revealed that PFS was associated with liver metastasis (hazard ratio [HR] 2.112, 95 % confidence interval [CI] 1.334–3.343, p = 0.001), previous HER2-TKI treatment (HR 2.019, 95 % CI 1.133–3.597, p = 0.017) and estrogen receptor positivity (HR 0.587, 95 % CI 0.370–0.934, p = 0.024). The toxicity was tolerable, with neutropenia being the most common treatment-related grade 3/4 AE (14.9 %). Inetetamab demonstrates effectiveness with a manageable safety profile, offering a promising therapeutic option for HER2-positive breast cancer patients who have shown resistance to prior anti-HER2 treatments. • Inetetamab is a novel recombinant humanized anti-HER2 monoclonal antibody, used with other drugs to treat HER2-positive breast cancer. • In a cohort of 141 patients, we observed a median PFS of 7.1 months, an ORR of 36.9 %, and a DCR of 80.9 %. • Liver metastasis, previous HER2-TKI treatment, and estrogen receptor positivity identified as predictive factors for PFS. • Inetetamab demonstrated a manageable safety profile, with neutropenia being the most frequently observed grade 3/4 adverse event. • Inetetamab is a new treatment option for HER2-positive MBC patients, especially those who have received other anti-HER2 treatments.Inetetamab is a new treatment option for HER2-positive MBC patients, especially those who have received other anti-HER2 treatments. [ABSTRACT FROM AUTHOR]

Adding CDK4/6 inhibitor dalpiciclib to fulvestrant significantly prolonged progression-free survival in patients with hormone receptor-positive, HER2-negative advanced breast cancer progressing after endocrine therapy. We aimed to assess the efficacy and safety of dalpiciclib plus letrozole or anastrozole in patients with hormone receptor-positive, HER2-negative advanced breast cancer who had no previous systemic therapy in the advanced setting. DAWNA-2 is a randomised, double-blind, placebo-controlled, phase 3 trial done at 42 hospitals in China. Eligible patients were aged 18–75 years, of any menopausal status, had an ECOG performance status of 0–1, and had pathologically confirmed hormone receptor-positive, HER2-negative untreated advanced breast cancer. Patients were randomly assigned (2:1) to receive oral dalpiciclib (150 mg per day for 3 weeks, followed by 1 week off) or matching placebo. Both groups also received endocrine therapy: either 2·5 mg letrozole or 1 mg anastrozole orally once daily continuously. Randomisation was using an interactive web response system (block size of six) and stratified according to visceral metastasis, previous endocrine therapy in the adjuvant or neoadjuvant setting, and endocrine therapy partner. All investigators, patients, and the funders of the study were masked to group allocation. We present the results of the preplanned interim analyses for the primary endpoint of investigator-assessed progression-free survival, which was assessed in all randomly assigned patients who met the eligibility criteria by intention-to treat. Safety was analysed in all randomly assigned patients who received at least one dose of study treatment. The superiority boundary was calculated as a one-sided p value of 0·0076 or less. This trial is registered with ClinicalTrials.gov , NCT03966898 , and is ongoing but closed to recruitment. Between July 19, 2019, and Dec 25, 2020, 580 patients were screened and 456 were eligible and randomly assigned to the dalpiciclib group (n=303) or placebo group (n=153). At data cutoff (June 1, 2022), median follow-up was 21·6 months (IQR 18·3–25·9), and 103 (34%) of 303 patients in the dalpiciclib group and 83 (54%) of 153 patients in the placebo group had disease progression or died. Median progression-free survival was significantly longer in the dalpiciclib group than in the placebo group (30·6 months [95% CI 30·6–not reached] vs 18·2 months [16·5–22·5]; stratified hazard ratio 0·51 [95% CI 0·38–0·69]; one-sided log-rank p<0·0001). Adverse events of grade 3 or 4 were reported in 271 (90%) of 302 patients in the dalpiciclib group and 18 (12%) of 153 patients in the placebo group. The most common adverse events of grade 3 or 4 were neutropenia (259 [86%] in the dalpiciclib group vs none in the placebo group) and leukopenia (201 [67%] vs none). Serious adverse events were reported for 36 (12%) patients in the dalpiciclib group and ten (7%) patients in the placebo group. Two treatment-related deaths occurred, both in the dalpiciclib group (deaths from unknown causes). Our findings suggest that dalpiciclib plus letrozole or anastrozole could be a novel standard first-line treatment for patients with hormone receptor-positive, HER2-negative advanced breast cancer, and is an alternative option to the current treatment landscape. Jiangsu Hengrui Pharmaceuticals and Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences. For the Chinese translation of the abstract see Supplementary Materials section. [ABSTRACT FROM AUTHOR]

Background: Despite therapeutic advances in HER2-positive metastatic breast cancer, resistance to trastuzumab inevitably develops. In the PHOEBE study, we aimed to assess the efficacy and safety of pyrotinib (an irreversible pan-HER inhibitor) plus capecitabine after previous trastuzumab.Methods: This is an open-label, randomised, controlled, phase 3 trial done at 29 hospitals in China. Patients with pathologically confirmed HER2-positive metastatic breast cancer, aged 18-70 years, who had an Eastern Cooperative Oncology Group performance status of 0 or 1, and had been previously treated with trastuzumab and taxanes were randomly assigned (1:1) to receive oral pyrotinib 400 mg or lapatinib 1250 mg once daily plus oral capecitabine 1000 mg/m2 twice daily on days 1-14 of each 21-day cycle. Randomisation was done via a centralised interactive web-response system with a block size of four or six and stratified by hormone receptor status and previous lines of chemotherapy for metastatic disease. The primary endpoint was progression-free survival according to masked independent central review. Efficacy and safety were assessed in all patients who received at least one dose of the study drugs. Results presented here are from a prespecified interim analysis. This study is registered with ClinicalTrials.gov, NCT03080805.Findings: Between July 31, 2017, and Oct 30, 2018, 267 patients were enrolled and randomly assigned. 134 patients received pyrotinib plus capecitabine and 132 received lapatinib plus capecitabine. At data cutoff of the interim analysis on March 31, 2019, median progression-free survival was significantly longer with pyrotinib plus capecitabine (12·5 months [95% CI 9·7-not reached]) than with lapatinib plus capecitabine (6·8 months [5·4-8·1]; hazard ratio 0·39 [95% CI 0·27-0·56]; one-sided p<0·0001). The most common grade 3 or worse adverse events were diarrhoea (41 [31%] in the pyrotinib group vs 11 [8%] in the lapatinib group) and hand-foot syndrome (22 [16%] vs 20 [15%]). Serious adverse events were reported for 14 (10%) patients in the pyrotinib group and 11 (8%) patients in the lapatinib group. No treatment-related deaths were reported in the pyrotinib group and one sudden death in the lapatinib group was considered treatment related.Interpretation: Pyrotinib plus capecitabine significantly improved progression-free survival compared with that for lapatinib plus capecitabine, with manageable toxicity, and can be considered an alternative treatment option for patients with HER2-positive metastatic breast cancer after trastuzumab and chemotherapy.Funding: Jiangsu Hengrui Medicine and National Key R&D Program of China.Translations: For the Chinese translation of the abstract see Supplementary Materials section. [ABSTRACT FROM AUTHOR]