Palbociclib in highly pretreated metastatic ER-positive HER2-negative breast cancer

Enhancer demethylation-regulated gene score identified molecular subtypes, inspiring immunotherapy or CDK4/6 inhibitor therapy in oesophageal squamous cell carcinoma

BACKGROUND

The 5-year survival rate of oesophageal squamous cell carcinoma (ESCC) is approximately 20%. The prognosis and drug response exhibit substantial heterogeneity in ESCC, impeding progress in survival outcomes. Our goal is to identify a signature for tumour subtype classification, enabling precise clinical treatments.

METHODS

Utilising pre-treatment multi-omics data from an ESCC dataset (n = 310), an enhancer methylation-eRNA-target gene regulation network was constructed and validated by in vitro experiments. Four machine learning methods collectively identified core target genes, establishing an Enhancer Demethylation-Regulated Gene Score (EDRGS) model for classification. The molecular function of EDRGS subtyping was explored in scRNA-seq (n = 60) and bulk-seq (n = 310), and the EDRGS's potential to predict treatment response was assessed in datasets of various cancer types.

FINDINGS

EDRGS stratified ESCCs into EDRGS-high/low subtypes, with EDRGS-high signifying a less favourable prognosis in ESCC and nine additional cancer types. EDRGS-high exhibited an immune-hot but immune-suppressive phenotype with elevated immune checkpoint expression, increased T cell infiltration, and IFNγ signalling in ESCC, suggesting a better response to immunotherapy. Notably, EDRGS outperformed PD-L1 in predicting anti-PD-1/L1 therapy effectiveness in ESCC (n = 42), kidney renal clear cell carcinoma (KIRC, n = 181), and bladder urothelial carcinoma (BLCA, n = 348) cohorts. EDRGS-low showed a cell cycle-activated phenotype with higher CDK4 and/or CDK6 expression, demonstrating a superior response to the CDK4/6 inhibitor palbociclib, validated in ESCC (n = 26), melanoma (n = 18), prostate cancer (n = 15) cells, and PDX models derived from patients with pancreatic cancer (n = 30).

INTERPRETATION

Identification of EDRGS subtypes enlightens ESCC categorisation, offering clinical insights for patient management in immunotherapy (anti-PD-1/L1) and CDK4/6 inhibitor therapy across cancer types.

FUNDING

This study was supported by funding from the National Key R&D Program of China (2021YFC2501000, 2020YFA0803300), the National Natural Science Foundation of China (82030089, 82188102), the CAMS Innovation Fund for Medical Sciences (2021-I2M-1-018, 2022-I2M-2-001, 2021-I2M-1-067), the Fundamental Research Funds for the Central Universities (3332021091).

Phase II study of apatinib plus exemestane in estrogen receptor-positive, human epidermal growth factor receptor 2-negative metastatic breast cancer

PURPOSE

Apatinib is a tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor (VEGFR)-2. This study was conducted to assess the efficacy and safety of apatinib combined with exemestane in patients with estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC).

METHODS

This single-center, single-arm phase II study enrolled patients with ER+/HER2- MBC progressed on previous letrozole or anastrozole. Stratified analysis was performed according to the number of chemotherapy regimens for metastatic disease. The primary endpoint was progression free survival (PFS). Secondary endpoints included objective response rate (ORR), disease control rate (DCR), clinical benefit rate (CBR), overall survival (OS) and toxicity. Patients received apatinib at a starting dose of 500 mg/d and exemestane 25 mg/d on days 1-28 of each 4-week cycle.

RESULTS

Thirty patients were enrolled with median four prior anticancer therapies. Eighty percent of patients received chemotherapy for metastatic disease. The median PFS (mPFS) and OS were 5.6 (95%CI: 4.3-6.9) months and 15.7 (95% CI: 9.7-21.7) months, respectively. The ORR, DCR, and CBR were 21.4%, 71.4%, and 46.4%, respectively. Patients with 0-1 line chemotherapy for MBC showed a slightly longer mPFS compared to those with ≥2 lines chemotherapy (mPFS: 6.4 months vs 4.8 months, P = .090). Most of the AEs were grade 1/2. One patient (3.3%) who suffered bone marrow metastases experienced grade 4 thrombocytopenia, and 14 experienced grade 3 AEs. Fifty percent of patients were given reduced dose for apatinib.

CONCLUSIONS

Apatinib plus exemestane exhibited objective efficacy in patients with ER+/HER2- MBC who have failed multiple lines of treatment. The AEs of apatinib required close monitoring and most of patients were well tolerated.

Treatment patterns, effectiveness, and patient-reported outcomes of palbociclib therapy in Chinese patients with advanced breast cancer: A multicenter ambispective real-world study

BACKGROUND

Palbociclib was the only available cyclin-dependent kinase 4/6 inhibitor in China until very recently, and its effect has not been systemically evaluated among Chinese patients. This study aims to assess the efficacy, safety and patient-reported outcomes (PROs) of palbociclib plus endocrine therapy (ET) in real-world China.

METHODS

An ambispective cohort study was conducted on patients with advanced HR+HER2- breast cancer who received palbociclib between July 2018, and November 2020 and were enrolled from 12 hospitals. Treatment patterns, survival outcomes, and safety events were documented, and PROs (European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 items [EORTC QLQ-C30] and EuroQoL 5 dimensions [EQ-5D]) were analyzed. The Kaplan-Meier method was used to visualize and estimate the median progression-free survival (mPFS). Log-rank tests, Cox regressions, t tests, and chi-square tests were performed for comparison.

RESULTS

A total of 190 patients (median follow-up of 18.0 months) were enrolled. Palbociclib was mostly combined with aromatase inhibitors (66.3%), fulvestrant (32.6%), and tamoxifen (1.1%). The mPFS values were 21.0, 14.0, and 7.0 months with palbociclib administered in first- (n = 83), second- (n = 41) and subsequent-line settings (n = 66), respectively. Endocrine sensitivity was significantly associated with patient prognosis (mPFS: 23.0, 12.0, and 6.0 months for endocrine naïve, acquired, and primary resistant patients, respectively, p < 0.01). The outcome was worse for patients who failed to meet the inclusion criteria of PALOMA-3 than for those who met the criteria (later-line: 6.0 months vs. 9.0 months). The most common adverse events (AEs) were neutropenia (74.2%; grade 3/4: 30.0%), fatigue (48.4%), anemia (32.6%), and thrombocytopenia (22.1%). PRO data suggested that palbociclib plus ET significantly improved cognitive and emotional function, pain symptoms, and overall quality of life.

CONCLUSIONS

Palbociclib is effective for front-line use and for treating endocrine-sensitive patients in real-world China and is generally well tolerated. The prevalence of AEs in the Chinese population is different from that reported in the PALOMA-2/3 trials.

Ki67 and progesterone receptor status predicts sensitivity to palbociclib: a real-world study

Background

Palbociclib combined with endocrine therapy has been approved as a front-line treatment for hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) advanced breast cancer (ABC). A key challenge remains to uncover biomarkers to identify those patients who may benefit from palbociclib treatment.

Methods

We retrospectively analyzed the values of Ki67 and progesterone receptor (PR) as detected by immunohistochemistry in 81 ABC patients with palbociclib and hormone therapy treatment, and evaluated the impact on progression-free survival (PFS).

Results

In the total population, women with Ki67 ≥14% had marginally significantly shorter PFS than those with Ki67 <14% (P=0.062). Patients with Ki67 ≥30% had significantly shorter PFS than those with Ki67 <30% (P=0.048). Meanwhile, PR ≥20% was associated with longer PFS. Moreover, the change of Ki67 or PR from primary tissue to metastatic lesions was related to PFS. As for the hormone therapy subgroup, there were significant associations between Ki67 and PR levels and PFS in the aromatase inhibitors (AIs) subgroup. Patients with Ki67 ≥14% or Ki67 ≥30% had shorter PFS than those with Ki67 <14% or Ki67 <30%, respectively (P=0.024, P<0.001). Additionally, the change of Ki67 or PR from primary tissue to metastatic lesions was related to PFS. When both Ki67 and PR were considered, there were significant differences between the different cohorts. Compared with patients with Ki67 ≥14% and PR <20%, those with Ki67 <14% and PR ≥20% had significantly longer PFS. In addition, patients with Ki67 <30% and PR ≥20% had significantly longer PFS than those with Ki67 ≥30% and PR <20%. Furthermore, in the AI cohort, patients with Ki67 <14% and PR ≥20% had significantly longer PFS than those with Ki67 ≥14% and PR <20%. Women with Ki67 <30% and PR ≥20% had significantly longer PFS than those with Ki67 ≥30% and PR <20%.

Conclusions

The present study indicates that both Ki67 and PR have great impacts on palbociclib and hormone therapy and may contribute to selecting more effective partners for palbociclib.

Patterns of treatment and outcome of palbociclib plus endocrine therapy in hormone receptor-positive/HER2 receptor-negative metastatic breast cancer: a real-world multicentre Italian study

Background

The CDK4/6 inhibitor palbociclib combined with endocrine therapy (ET) has proven to prolong progression-free survival (PFS) in women with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC). Few data are available regarding the efficacy of such a regimen outside the clinical trials.

Patients and methods

This is a multicentre prospective real-world experience aimed at verifying the outcome of palbociclib plus ET in an unselected population of MBC patients. The primary aim was the clinical benefit rate (CBR); secondary aims were the median PFS, overall survival (OS) and safety. Patients received palbociclib plus letrozole 2.5 mg (cohort A) or fulvestrant 500 mg (cohort B).

Results

In total, 191 patients (92 in cohort A, 99 in cohort B) were enrolled and treated, and 182 were evaluable for the analysis. Median age was 62 years (range 47-79); 54% had visceral involvement; 28% of patients had previously performed one treatment line (including chemotherapy and ET), 22.6% two lines and 15.9% three. An overall response rate of 34.6% was observed with 11 (6.0%) complete responses and 52 (28.6%) partial responses. Stable disease was achieved by 78 patients (42.9%) with an overall CBR of 59.8%. At a median follow-up of 24 months (range 6-32), median PFS was 13 months without significant differences between the cohorts. When analysed according to treatment line, PFS values were significantly prolonged when palbociclib-based therapy was administered as first-line treatment (14.0 months), to decrease progressively in second and subsequent lines (11.7 and 6.7 months, respectively). Median OS was 25 months, ranging from 28.0 months in 1st line to 18.0 and 13.0 months in 2nd and subsequent lines, respectively.

Conclusions

Our data indicate that palbociclib plus ET is active and safe in HR+/HER2- MBC, also suggesting a better performance of the combinations in earlier treatment lines.

Prolonged benefit from palbociclib plus letrozole in heavily pretreated advanced male breast cancer: case report

INTRODUCTION

Breast cancer in men is less common than in women and treatment recommendations are often derived from clinical trials exclusively involving women. Data on efficacy of CDK 4/6 inhibitors, which are the mainstay of treatment for hormone receptor-positive/HER2-negative advanced breast cancer, are lacking in male patients.

CASE REPORT

We present a clinical case of prolonged benefit from palbociclib in combination with letrozole and LHRH analogue in a man who had previously been treated with six lines of endocrine therapies and chemotherapy regimens but was still in excellent clinical condition.

CONCLUSIONS

This clinical case demonstrates that male breast cancer stands out as an endocrine-sensitive disease, which could potentially benefit from CDK 4/6 inhibitors in combination with endocrine agents even in very heavily pretreated settings of disease, underscoring both the importance of an accurate selection of patients for later treatment lines, taking into account disease history and previous treatment responses, and the peculiarity of breast cancer in men, which deserves dedicated clinical trials to tailor future recommendations.

Palbociclib combined with endocrine therapy in heavily pretreated HR+/HER2- advanced breast cancer patients: Results from the compassionate use program in Spain (PALBOCOMP)

Background

This study evaluated efficacy and safety of palbociclib, a CDK4/6 inhibitor, in heavily-pretreated hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR⁺/HER2^-) metastatic breast cancer (mBC) patients during the compassionate use program in Spain from February 2015 to November 2017.

Patients and methods

Patient data were collected retrospectively from 35 hospitals in Spain. Patients with HR⁺/HER2^- mBC who had progressed on ≥4 treatments for advanced disease were eligible.

Results

A total of 219 patients received palbociclib in combination with aromatase inhibitors (110; 50.2%), fulvestrant (87; 39.7%), tamoxifen (8; 3.6%) or as single agent (10; 4.6%). Mean age of the patients was 58 years; 31 patients (16.1%) were premenopausal and 162 (83.9%) were postmenopausal at the beginning of treatment with palbociclib. Patients had received a median of 3 previous lines of endocrine therapy (ET) for advanced disease. Real-world tumor response (rwTR) and clinical benefit rate were 5.9% (n = 13) and 46.2% (n = 101), respectively. The median real world progression-free survival (rwPFS) was 6.0 months (95% CI 5.7–7.0) and the median overall survival was 19.0 months (95% CI 16.4–21.7). Subgroup analysis revealed a significant difference in median rwPFS in patients treated with palbociclib plus fulvestrant depending on the duration of prior treatment with fulvestrant monotherapy (>6 versus ≤6 months; HR 1.93, 95% CI 1.37–2.73, p < 0.001). The most frequently reported toxicities were neutropenia, asthenia, thrombopenia and anemia.

Conclusions

Palbociclib can be an effective and safe treatment option in patients with heavily pretreated endocrine-sensitive mBC, especially in those with longer PFS to previous ET.

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CDK4/6 inhibitors combined with endocrine therapy have been widely accepted as a new standard therapy for hormone receptor-positive metastatic breast cancer patients in first or second line.

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Palbociclib alone or in combination with aromatase inhibitors, fulvestrant, or tamoxifen was effective and safe in heavily pretreated HR⁺/HER2^- metastatic breast cancer patients.

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Palbociclib could be of higher benefit to patients with endocrine-sensitive disease that had a long duration of response to previous endocrine therapy.

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Real-world evidence of effectiveness and safety of use of palbociclib in heavily pretreated advanced breast cancer patients complements data from randomized clinical trials.

Efficacy and safety of cyclin dependent kinases 4/6 inhibitors in the treatment of metastatic breast cancer: a real-world experience

BACKGROUND

Randomized trials have shown survival gains for patients with metastatic breast cancer (BC) treated with CDK4/6 inhibitors (CDK4/6i) in combination with endocrine agents. It is not unlikely that there may be discrepancies between the generally fit clinical study population and the real-world setting that could affect adherence to treatment guidelines, tolerance to treatment and outcome.

MATERIAL AND METHODS

Consecutive patients with metastatic or locally advanced and unresectable BC that were treated between July 2017 and January 2020 at Karolinska University Hospital, Stockholm, Sweden and that had received at least one dose of CDK4/6i were included in this retrospective study. The primary endpoint was safety, including toxicity according to CTCAE 5 and rates of treatment interruptions, dose reductions and discontinuations. The secondary endpoint was efficacy based on the treating physicians' assessments in terms of progression free (PFS) and overall survival (OS), as well as the factors associated with patient outcome.

RESULTS

Eighty-eight patients were included in the analysis, with a median age of 67.2 years. Grade 4 neutropenia occurred in 9.1% of patients and one episode of neutropenic infection was observed. Dose reductions were made in 38.6% of patients, while 11.4% discontinued treatment due to toxicity, most commonly non-hematologic. After a median follow-up of 18.33 months, median PFS was 13.30 months (95% CI, 11.39-15.21) and median OS could yet not be estimated. In multivariable analysis, number of prior chemotherapy lines was an independent predictor for shorter PFS (HR = 3.28, 95% CI 1.50-7.16, p = .003).

CONCLUSIONS

CDK4/6i administered in a real-world setting exhibits a similar toxicity profile but higher incidence of treatment discontinuation compared to randomized trials. Efficacy of CDK4/6i among patients pretreated with multiple therapy lines is markedly reduced.

Efficacy and safety of selective cyclin-dependent kinases 4/6 inhibitors in hormone-receptor-positive, HER2-negative advanced breast cancer - results from a real-world setting

BACKGROUND

Selective cyclin-dependent kinases 4/6 inhibitors (CDKi) have become the standard of care in patients with hormone receptor (HR)-positive, HER2-negative advanced breast cancer (ABC). We performed retrospective analysis in patients treated with CDKi in the first year of their routine clinical use in Slovenia.

METHODS

The primary goals were time-to-treatment failure (TTF) and overall survival (OS), analysed via Kaplan-Meier method, the secondary goals were clinical benefit rate (CBR) and safety.

RESULTS

Overall, 218 patients' data were evaluated. The median age was 61.8 years (30.6-84.6). The median number of previous ET lines for ABC was 2 (range 0-5). At the time of inclusion, 128 patients (58.7%) had visceral metastases, 45 patients (20.6%) had bone-only disease. At the median follow-up of 15.2 months, disease progressed in 74 patients and 60 patients died. The median TTF was 8.3 months for the whole group, 19.3, 10.3 and 5.5 months for patients treated in the first-, second- and further lines of systemic therapy, respectively. The median OS from the start of CDKi treatment was not reached in any of the groups. CBR was 59.6% for the whole group, 42.7% for further lines of therapy. The most common grade 3/4 adverse event was neutropaenia in 108 patients (49.5%), followed by an increase of hepatic aminotransferases in 13 patients (6.0%).

CONCLUSIONS

Even in the diverse real-world population treatment with CDKi in combination with ET showed clinical benefit, most prominently in the first- and second lines of systemic therapy.

Palbociclib in metastatic breast cancer: current evidence and real-life data

The purpose of this review is to summarize the background and latest evidence for the use of palbociclib, an oral, first-in-class, highly selective cyclin-dependent kinase 4/6 inhibitor, in advanced breast cancer, with a focus on some of the unanswered questions about the performance of this agent in clinical practice. The available clinical data from both controlled clinical trials and real-life experiences concerning palbociclib-based combinations in patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) metastatic disease, including patient-reported outcomes and subgroup analyses, have been reviewed and discussed. Palbociclib significantly improved progression-free survival and clinical benefit rates when added to letrozole in postmenopausal women as initial endocrine-based therapy, and it prolonged progression-free survival and overall survival when added to fulvestrant in women who progressed on previous endocrine therapy in randomized clinical trials. Tolerability profile was manageable, with neutropenia occurring most commonly, without detrimental impact on quality of life. Available data from real-life experiences confirm the good performance of palbociclib in unselected, heavily pretreated populations. Palbociclib in combination with endocrine therapy is a valuable emerging option for patients with HR+/HER2- advanced or metastatic breast cancer. Further investigation is needed to provide solutions for palbociclib resistance and to identify the best sequence to use for the best patient benefit with a minimal toxicity.

Palbociclib plus endocrine therapy in HER2 negative, hormonal receptor-positive, advanced breast cancer: A real-world experience

Data from 423 human epidermal growth factor receptor 2-negative (HER2-), hormone receptor-positive (HR+) advanced breast cancer (aBC) patients treated with palbociclib and endocrine therapy (ET) were provided by 35 Italian cancer centers and analyzed for treatment outcomes. Overall, 158 patients were treated in first line and 265 in second/later lines. We observed 19 complete responses and 112 partial responses. The overall response rate (ORR) was 31% (95% confidence interval [CI], 26.6-35.4) and clinical benefit was 52.7% (95% CI, 48-57.5). ORR was negatively affected by prior exposure to everolimus/exemestane ( p = 0.002) and favorably influenced by early line-treatment ( p < 0.0001). At 6 months, median progression-free survival was 12 months (95% CI, 8-16) and median overall survival was 24 months (95% CI, 17-30). More favorable outcomes were associated with palbociclib in early lines, no visceral metastases and no prior everolimus/exemestane. The main toxicity reported was neutropenia. Our results provide further support to the use of palbociclib with ET in HER2-, HR+ aBC. Differences in outcomes across patients subsets remain largely unexplained.

Response evaluation with 18F-FDG PET/CT in metastatic breast cancer patients treated with Palbociclib: first experience in clinical practice

OBJECTIVE

Palbociclib is a cyclin-dependent kinase 4/6 inhibitor recently approved for treatment in advanced or metastatic breast cancer (BC) patients. The use of ¹⁸F-FDG PET/CT for chemo/endocrine therapy response assessment in BC patients is well reported in the literature, but no studies have evaluated its role for assessing Palbociclib efficacy in clinical practice. Our study aimed to evaluate the potential role of ¹⁸F-FDG PET/CT in this setting.

METHODS

In 12 metastatic BC patients (mean age = 62 ± 10 years) treated with Palbociclib plus endocrine therapy and who underwent a baseline and post-therapy ¹⁸F-FDG PET/CT, we retrospectively compared the Metabolic Response Evaluation (MRE, based on PET/CT) to the Standard Response Evaluation (SRE, based on clinico-laboratory and morphological data); we also assessed the influence of additional PET/CT information on the patients' management.

RESULTS

Compared to SRE, MRE increased the proportion of patients classified with progressive disease from 25 to 50% and differed from SRE in 8/12 patients: 3/8 shifted from stable disease or undetermined response to metabolic progression (more unfavorable category), 4/8 from stable disease to partial or complete metabolic response, and 1/8 from partial response to complete metabolic response (more favorable category). Additional PET/CT information led to a change in patients' management in 3/12 (25%) patients.

CONCLUSION

In BC patients treated with Palbociclib, additional ¹⁸F-FDG PET/CT information seems clinically useful, with respect to personalized management, to early intercept patients who should discontinue Palbociclib because of progressive disease and to select patients requiring a strict monitoring of additional metabolic findings. Further studies are needed to confirm these preliminary results.