Palbociclib plus letrozole as first-line therapy in estrogen receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer with extended follow-up

Management of hormone receptor-positive, human epidermal growth factor 2-negative metastatic breast cancer

Estrogen receptor (ER) is the major driver of most metastatic breast cancers (mBCs). Endocrine therapy (ET) is the most effective treatment for ER + mBC, but its effectiveness is limited by high rates of de novo and acquired resistance. A growing understanding of the biological characteristics and complexity of the ER pathway and the mechanisms of ET resistance has led to the development of a new generation of targeted therapies. One such mechanism is the cell cycle signaling pathways, which lead to the development of cyclin-dependent kinase 4/6 inhibitors (CDK4/6is) that have, in turn, transformed the management of such tumors. Another important mechanism is the alteration of the phosphatidylinositol 3'-kinase/AKT/mammalian target of rapamycin pathway. Drugs targeting each component of these pathways are currently used in clinical practice, and several more are in development. As a result, a myriad of new targeted therapies are consistently being added to the clinical oncologist armamentarium. Navigating the evolving and highly complex treatment landscape of HR + /HER2- mBC remains both an art and a challenge. In this review, we discuss the biological features of HR + /HER2- mBC and the different mechanisms of resistance to ET. We also discuss the management of mBC as the disease changes from endocrine-sensitive to endocrine-resistant.

Real-World Tumor Response of Palbociclib Plus Letrozole Versus Letrozole for Metastatic Breast Cancer in US Clinical Practice

BACKGROUND

Limited information exists regarding tumor response to palbociclib plus an aromatase inhibitor (AI) versus AI alone in real-world practice.

OBJECTIVE

To evaluate the real-world tumor response of palbociclib plus letrozole (PAL+LET) versus LET alone as first-line treatment for patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer (HR+/HER2‒ MBC) in routine US clinical practice.

PATIENTS AND METHODS

This retrospective analysis included HR+/HER2‒ MBC patients who initiated PAL+LET or LET as first-line treatment between February 2015 and September 2018 in the Flatiron Health Analytics database. Patients were followed until December 2018. Real-world best tumor response (rwBTR) was determined based on physicians' assessment of radiologic evidence for change in burden of disease.

RESULTS

Of the 1383 eligible patients who initiated PAL+LET or LET as first-line therapy in the Flatiron database, 968 patients had ≥ 1 tumor response assessment (662 received PAL+LET and 306 received LET). The rwBTR rate (complete response+partial response) in the first-line setting was 59.8% in the PAL+LET group and 39.2% in the LET group (odds ratio 2.31 (95% CI 1.75‒3.04), P < 0.0001). After 1:1 propensity-score matching, the rwBTR rate was 58.6% in the PAL+LET group versus 39.1% in the LET group (odds ratio 2.21 (95% CI 1.50‒3.25), P < 0.0001).

CONCLUSIONS

This real-world analysis demonstrated that HR+/HER2‒ MBC patients were more likely to respond to PAL+LET compared to LET. These findings further showed the effectiveness of PAL+LET therapy in the real-world setting and support the combination as a standard of care for MBC.

STUDY REGISTRATION

Pfizer; NCT04176354; registered November 25, 2019.

Targeting Pyruvate Kinase M2 Phosphorylation Reverses Aggressive Cancer Phenotypes

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype with low survival rate and a lack of biomarkers and targeted treatments. Here, we target pyruvate kinase M2 (PKM2), a key metabolic component of oncogenesis. In patients with TNBC, PKM2pS37 was identified as a prominent phosphoprotein corresponding to the aggressive breast cancer phenotype that showed a characteristic nuclear staining pattern and prognostic value. Phosphorylation of PKM2 at S37 was connected with a cyclin-dependent kinase (CDK) pathway in TNBC cells. In parallel, pyruvate kinase activator TEPP-46 bound PKM2pS37 and reduced its nuclear localization. In a TNBC mouse xenograft model, treatment with either TEPP-46 or the potent CDK inhibitor dinaciclib reduced tumor growth and diminished PKM2pS37. Combinations of dinaciclib with TEPP-46 reduced cell invasion, impaired redox balance, and triggered cancer cell death. Collectively, these data support an approach to identify PKM2pS37-positive TNBC and target the PKM2 regulatory axis as a potential treatment. SIGNIFICANCE: PKM2 phosphorylation marks aggressive breast cancer cell phenotypes and targeting PKM2pS37 could be an effective therapeutic approach for treating triple-negative breast cancer.

Multicentric real world evidence with palbociclib in hormone positive HER2 negative metastatic breast cancer in Indian population

The combination of cyclin dependent kinase 4/6 inhibitors with endocrine therapy is the standard therapy in hormone receptor positive HER-2 negative metastatic breast cancer (HR+/HER2− MBC). Several randomized trials have shown the benefits of this combination, however, real world evidence in the Indian patients is warranted. The present study reports the largest real world multicentric data from Indian population on the use of Palbociclib in HR+/HER2− MBC. A multicentric study on the HR+/HER2− MBC patients who received palbociclib with hormonal agent (Aromatase inhibitors/Fulvestrant) between February 2017 and May 2020 was conducted. Clinical and demographic information and survival data was retrieved from the Hospital medical records. Among a total of 188 patients, 57% patients were premenopausal and 17% patients had bone only disease. Altogether, 115 (61%) patients received palbociclib with Aromatase inhibitors in the first line whereas 73 (39%) patients received it in the second line with Fulvestrant. The median follow up period with advanced disease was 13 months. The median progression free survival in the first line and second line was 20.2 months and 12 months, respectively (p-value < 0.0001). The objective response rate was 80% and 47.9% in first and second lines, respectively. Dose interruptions/ discontinuation were done in 14.9% and 2.7% patients in the first and second lines, respectively. In terms of toxicity, 10% patients had grade 3–4 adverse events. The present real world data of the use of palbociclib in Indian population suggests similar effectiveness to previously published real world evidences and has been adapted as the standard of care in the first and second line treatment of HR+/HER2− MBC.

Optimizing treatment selection, and sequencing decisions for Management of HR-Positive, HER2-Negative advanced breast cancer - Proceedings from breast cancer expert group meeting

PURPOSE

The therapeutic landscape of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (mBC) has evolved considerably with the introduction of newer targeted agents and their combinations with endocrine therapies. In this scenario, optimizing treatment selection and sequencing is daunting for clinicians. The purpose of this review is to provide evidence-based answers to key clinical questions on treatment selection and sequencing for the management of HR + HER2 - mBC.

DESIGN

A panel of nine key opinion leaders from Argentina, Brazil, Colombia, Mexico, Moscow, Singapore, South Korea, Taiwan, and UAE convened in October 2018. They reviewed the literature and formulated answers to clinical questions on optimizing the management of HR + HER2 - mBC.

RESULTS

Evidence-based answers were formulated for: (1) optimal initial treatment choice; (2) ovarian function suppression, optimal endocrine partner, and role of cyclin-dependent kinase 4/6 (CDK4/6) inhibitors (in premenopausal women); (3) better first-line standard of care than aromatase inhibitors; (4) preferred second-line treatment; (5) treatment of oligometastatic disease; (6) factors influencing first-line single-agent endocrine therapy choice; (7) influence of endocrine resistance on treatment selection; (8) optimal maintenance regimen in visceral crisis; and (9) need for a breast cancer registry for patients with HR + HER2 - mBC. The panel also proposed a treatment-sequencing algorithm for the management of HR + HER2 - mBC.

CONCLUSION

The current article will serve as a comprehensive guide for optimizing the management of HR + HER2 - mBC. The proposed breast cancer registry will help identify unmet needs and develop strategic regional policies to help improve access to optimized care for HR + HER2 - mBC.

Radiological and pathological assessment of response to neoadjuvant CDK4/6 inhibitor and endocrine treatments in a real-life setting-initial results

BACKGROUND

Neoadjuvant endocrine therapy is an alternative to neoadjuvant chemotherapy in women with inoperable luminal-like breast cancers. Neoadjuvant cyclin-dependent kinase 4/6 inhibitor treatment combined with endocrine treatment (CDK4/6I + E) is interesting given the combination's utility in the treatment of metastatic breast cancer. Currently, the literature on the radiological response evaluation of patients treated with neoadjuvant CDK4/6I + E in a real-life setting is scarce.

PURPOSE

To conduct a radiological response evaluation of patients treated with neoadjuvant CDK4/6I + E in a real-life setting.

MATERIAL AND METHODS

We retrospectively reviewed clinical, pathological, and radiological findings of six patients with luminal-like breast cancers treated with neoadjuvant CDK4/6I + E treatment. The radiological neoadjuvant CDK4/6I + E response was evaluated with the RECIST 1.1 criteria and the pathological residual disease was assessed using the Residual Cancer Burden (RBC) criteria.

RESULTS

None of the patients achieved a complete radiological magnetic resonance imaging (MRI)-determined response or a complete pathological response; three (50%) patients had a partial radiological response; in the three others, the disease remained stable radiologically. All of the tumors were rendered susceptible to surgical treatment. Two out of six (33.3%) patients had a moderate response (RBC-II); four (66.7%) had an extensive residual disease (RBC-III) in the final surgical sample.

CONCLUSION

Although none of the patients achieved a pathologically complete response, neoadjuvant CDK4/6I + E treatment rendered all tumors operable. MRI appears to be reliable in the assessment of the neoadjuvant CDK4/6I + E treatment response in a real-life setting. Larger studies are warranted to confirm these results.

Endocrine Treatment and Targeted Therapy for Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Metastatic Breast Cancer: ASCO Guideline Update

PURPOSE

To update recommendations of the ASCO systemic therapy for hormone receptor (HR)-positive metastatic breast cancer (MBC) guideline.

METHODS

An Expert Panel conducted a systematic review to identify new, potentially practice-changing data.

RESULTS

Fifty-one articles met eligibility criteria and form the evidentiary basis for the recommendations.

RECOMMENDATIONS

Alpelisib in combination with endocrine therapy (ET) should be offered to postmenopausal patients, and to male patients, with HR-positive, human epidermal growth factor receptor 2 (HER2)-negative, PIK3CA-mutated, ABC, or MBC following prior endocrine therapy with or without a cyclin-dependent kinase (CDK) 4/6 inhibitor. Clinicians should use next-generation sequencing in tumor tissue or cell-free DNA in plasma to detect PIK3CA mutations. If no mutation is found in cell-free DNA, testing in tumor tissue, if available, should be used as this will detect a small number of additional patients with PIK3CA mutations. There are insufficient data at present to recommend routine testing for ESR1 mutations to guide therapy for HR-positive, HER2-negative MBC. For BRCA1 or BRCA2 mutation carriers with metastatic HER2-negative breast cancer, olaparib or talazoparib should be offered in the 1st-line through 3rd-line setting. A nonsteroidal aromatase inhibitor (AI) and a CDK4/6 inhibitor should be offered to postmenopausal women with treatment-naïve HR-positive MBC. Fulvestrant and a CDK4/6 inhibitor should be offered to patients with progressive disease during treatment with AIs (or who develop a recurrence within 1 year of adjuvant AI therapy) with or without one line of prior chemotherapy for metastatic disease, or as first-line therapy. Treatment should be limited to those without prior exposure to CDK4/6 inhibitors in the metastatic setting.Additional information can be found at www.asco.org/breast-cancer-guidelines.

Efficacy and safety of palbociclib in patients with estrogen receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer with preexisting conditions: A post hoc analysis of PALOMA-2

Objective

In the PALOMA-2 trial, palbociclib in combination with letrozole prolonged progression-free survival (PFS) and exhibited an acceptable safety profile in patients with estrogen receptor–positive/human epidermal growth factor receptor 2–negative advanced breast cancer (ABC). This post hoc analysis of PALOMA-2 evaluated the efficacy and safety of palbociclib plus letrozole in patients with preexisting conditions grouped by Medical Dictionary for Regulatory Activities (MedDRA) System Organ Class (SOC).

Methods

Postmenopausal patients without prior treatment for ABC were randomized 2:1 to receive palbociclib (125 mg/d on a 3 weeks on/1 week off schedule) plus letrozole (2.5 mg/d, continuous) or placebo plus letrozole. Patients were grouped by the following MedDRA SOC preexisting conditions: gastrointestinal, musculoskeletal, metabolic, and vascular/cardiac. Median PFS was estimated by the Kaplan-Meier method, and treatment emergent adverse events (AEs) were compared between treatment arms within each preexisting condition subgroup.

Results

At baseline, 276 (41.4 %) patients had preexisting gastrointestinal disorders, 390 (58.6 %) had musculoskeletal disorders, 259 (38.9 %) had metabolic disorders, and 382 (57.4 %) had vascular/cardiac disorders. Baseline characteristics were similar between subgroups and between each arm within subgroups. Regardless of baseline preexisting condition, palbociclib plus letrozole prolonged PFS compared with placebo plus letrozole. Treatment-emergent AEs associated with palbociclib plus letrozole and dose modifications due to AEs were similar across preexisting condition subgroups.

Conclusion

This post hoc analysis of PALOMA-2 demonstrated a favorable effect of palbociclib on PFS and a safety profile consistent with previous observations, regardless of underlying preexisting condition. Pfizer Inc (NCT01740427).

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Preexisting conditions can affect the safety and efficacy of breast cancer therapies.

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This is a post hoc analysis of patients with preexisting conditions from PALOMA-2.

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Palbociclib prolonged median PFS, regardless of preexisting condition.

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Within each treatment arm, AEs were similar regardless of preexisting condition.

Elective Discontinuation of CDK4/6 Inhibitors in Patients with Metastatic Hormone Receptor-Positive, Her-2-Negative Breast Cancer: A Retrospective Single-Center Experience

INTRODUCTION

Cyclin-dependent 4/6 kinase (CDK4/6) inhibitors given with endocrine therapy until disease progression are standard of care in the treatment of women with advanced HR-positive Her-2-negative breast cancer. No data are available if therapy can be safely de-escalated to endocrine monotherapy in patients with long-lasting disease control.

METHODS

We performed a retrospective analysis on the clinical course of 22 patients at our center who received CDK4/6 inhibitors with aromatase inhibitors or fulvestrant. All patients had at least stable disease for >6 months and made a joint decision with their provider to electively discontinue CDK4/6 inhibitors. Best objective response (BOR) at treatment discontinuation, progression-free survival, and re-treatment characteristics were recorded.

RESULTS

Of 138 patients who received CDK4/6 inhibitors as first- or second-line therapy at our center, 22 met the inclusion criteria. Median duration of CDK4/6 treatment was 18 months (range 6-45). BOR was complete response in 1, partial response in 8, and stable disease in 13 patients. After a median duration of endocrine monotherapy of 9.5 months (range 5-44 months), 6 of 22 patients had progressive disease (1 local relapse and 5 systemic progression). All patients with disease progression had at least stable disease to chemotherapy (N = 1) or re-treatment with CDK4/6 inhibitors (N = 4).

CONCLUSION

Elective discontinuation of CDK4/6 inhibitors is feasible in patients with long-lasting disease stabilization. This strategy should be evaluated in prospective trials.

Demographic Characteristics and Treatment Patterns Among Patients Receiving Palbociclib for HR+/HER2- Advanced Breast Cancer: A Nationwide Real-World Experience

Background

This nationwide retrospective study reports data on the real-world use of the selective cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor palbociclib in a large population of advanced breast cancer (ABC) patients during a 2-year period in Hungary.

Methods

All patients with ABC who received palbociclib between May 1, 2017 and June 30, 2019 were included in the analysis. Patient demographic and clinical characteristics, disease-related factors and treatment patterns were examined during the early access program and in the regular reimbursement period.

Results

Altogether, 962 patients were included (mean age: 60.6 years). A total of 399 patients (41%) were treated with palbociclib plus aromatase inhibitors (P+AI), and 563 patients (59%) received palbociclib and fulvestrant (P+F). The most commonly prescribed AI was letrozole (n=359; 90%). Of those with metastatic disease (n=733; 76%), 241 patients (33%) had visceral metastases and 449 (61%) had bone-only disease. The majority of patients (79%) received palbociclib as first- or second-line therapy for ABC. The starting dose of palbociclib was 125 mg in 98% of patients; dose reductions were required in 32% of patients receiving P+AI and 31% of those treated with P+F. At the time of data collection, palbociclib therapy was ongoing in 270 patients (68%) in the P+AI group and 245 patients (44%) in the P+F group.

Conclusions

This nationwide analysis is the first to provide insights into the real-world use of palbociclib in a large patient population from a Central-Eastern European country. The findings confirm the good tolerability of palbociclib with similar dose reduction rates to those reported from registration trials.

First-Line Treatment with a Cyclin-Dependent Kinase 4/6 Inhibitor Plus an Aromatase Inhibitor for Metastatic Breast Cancer in Alberta

In this analysis, we describe population-based outcomes for first-line treatment with a cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) combined with an aromatase inhibitor (AI). All patients who were prescribed CDK4/6i + AI from January 2016 through June 2019 were included. Patient demographics, tumour and treatment characteristics were collected and described. Survival distributions were estimated using the Kaplan–Meier method. Multivariate analysis (MVA) was constructed to examine associations between potentially prognostic clinical variables and progression-free survival (PFS). In total, 316 patients were included. The median age was 61 years. After a median follow-up of 28.1 months, the median PFS was 37.9 months (95% CI, 26.7–NR). In the MVA, PR-negative tumour (HR, 2.37; 95% CI, 1.45–3.88; p = 0.001) and CDK4/6i dose reduction (HR, 1.51; 95% CI, 1.06–2.16; p = 0.022) predicted worse PFS. Median overall survival (OS) was not reached. The 30-month and 36-month OS rates were 74% and 68%, respectively. Of patients who progressed, 89% received second-line treatment. Median time to progression on second-line chemotherapy was 9.0 (5.8–17.6) months, and median time to progression on second-line hormonal therapy +/− targeted agent was 4.0 (3.4–8.6) months (p = 0.012). CDK4/6i + AI as first-line treatment for HR-positive, HER2-negative MBC in Alberta is justified based on favourable PFS and early OS outcomes.

[Targeting the cyclin-dependent kinases 4/6 in advanced breast cancers]

The historical median survival of advanced luminal breast cancer does not exceed four years. The deciphering of the mechanisms of resistance to hormone therapy has led to the development of inhibitors of cyclin D dependent kinases (CDK4 and 6). Three drugs, palbociclib, ribociclib and abemaciclib, very similar pharmacologically, have been evaluated in the context of pivotal, randomized phase III trials. Strikingly and regardless of the endocrine therapy backbone, and in both hormone-sensitive and hormone-resistant patients, the addition of a CDK4 / 6 inhibitor doubles progression-free survival with a hazard ratio always around 0.55. The benefit in overall survival begins to be demonstrated. This review presents all published results, as well as the main safety data.

Role of the Combination of Cyclin-Dependent Kinase Inhibitors (CDKI) and Radiotherapy (RT) in the Treatment of Metastatic Breast Cancer (MBC): Advantages and Risks in Clinical Practice

Targeting cell cycle has become the gold standard for metastatic breast cancer (MBC), being cyclin-dependent kinase inhibitors (CDKIs) cornerstones of its treatment, alongside radiotherapy (RT). To date, no definite evidence regarding safety and efficacy of the combination of CDKIs plus radiotherapy (RT) is currently available. Purpose of this review is to collect data in favor or against the feasibility of the association of CDKIs + RT, describing its potential adverse events. Our review shows how CDKI + RT allows an overall satisfying disease control, proving to be effective and causing a grade of toxicity mainly influenced by the site of irradiation, leaning to favourable outcomes for sites as liver, spine or brain and to poorer outcomes for thoracic lesions or sites close to viscera; controversial evidence is instead for bone treatment. Toxicity also varies from patient to patient. To sum up, our contribution enriches and enlightens a still indefinite field regarding the feasibility of CDKIs + RT, giving cues for innovative clinical management of hormone-responsive MBC.

A multicenter analysis of treatment patterns and clinical outcomes of subsequent therapies after progression on palbociclib in HR+/HER2- metastatic breast cancer

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.

Evaluation of the Association of Polymorphisms With Palbociclib-Induced Neutropenia: Pharmacogenetic Analysis of PALOMA-2/-3

BACKGROUND

The most frequently reported treatment-related adverse event in clinical trials with the cyclin-dependent kinase 4/6 (CDK4/6) inhibitor palbociclib is neutropenia. Allelic variants in ABCB1 and ERCC1 might be associated with early occurrence (i.e., end of week 2 treatment) of grade 3/4 neutropenia. Pharmacogenetic analyses were performed to uncover associations between single nucleotide polymorphisms (SNPs) in these genes, patient baseline characteristics, and early occurrence of grade 3/4 neutropenia.

MATERIALS AND METHODS

ABCB1 (rs1045642, rs1128503) and ERCC1 (rs3212986, rs11615) were analyzed in germline DNA from palbociclib-treated patients from PALOMA-2 (n = 584) and PALOMA-3 (n = 442). SNP, race, and cycle 1 day 15 (C1D15) absolute neutrophil count (ANC) data were available for 652 patients. Univariate and multivariable analyses evaluated associations between SNPs, patient baseline characteristics, and early occurrence of grade 3/4 neutropenia. Analyses were stratified by Asian (n = 122) and non-Asian (n = 530) ethnicity. Median progression-free survival (mPFS) was estimated using the Kaplan-Meier method. The effect of genetic variants on palbociclib pharmacokinetics was analyzed.

RESULTS

ABCB1 and ERCC1_rs11615 SNP frequencies differed between Asian and non-Asian patients. Multivariable analysis showed that low baseline ANC was a strong independent risk factor for C1D15 grade 3/4 neutropenia regardless of race (Asians: odds ratio [OR], 6.033, 95% confidence interval [CI], 2.615-13.922, p < .0001; Non-Asians: OR, 6.884, 95% CI, 4.138-11.451, p < .0001). ABCB1_rs1128503 (C/C vs. T/T: OR, 0.57, 95% CI, 0.311-1.047, p = .070) and ERCC1_rs11615 (A/A vs. G/G: OR, 1.75, 95% CI, 0.901-3.397, p = .098) were potential independent risk factors for C1D15 grade 3/4 neutropenia in non-Asian patients. Palbociclib mPFS was consistent across genetic variants; exposure was not associated with ABCB1 genotype.

CONCLUSION

This is the first comprehensive assessment of pharmacogenetic data in relationship to exposure to a CDK4/6 inhibitor. Pharmacogenetic testing may inform about potentially increased likelihood of patients developing severe neutropenia (NCT01740427, NCT01942135).

IMPLICATIONS FOR PRACTICE

Palbociclib plus endocrine therapy improves hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer outcomes, but is commonly associated with neutropenia. Genetic variants in ABCB1 may influence palbociclib exposure, and in ERCC1 are associated with chemotherapy-induced severe neutropenia. Here, the associations of single nucleotide polymorphisms in these genes and baseline characteristics with neutropenia were assessed. Low baseline absolute neutrophil count was a strong risk factor (p < .0001) for grade 3/4 neutropenia. There was a trend indicating that ABCB1_rs1128503 and ERCC1_rs11615 were potential risk factors (p < .10) for grade 3/4 neutropenia in non-Asian patients. Pharmacogenetic testing could inform clinicians about the likelihood of severe neutropenia with palbociclib.

CDK4/6 inhibitors in HR+/HER2- advanced/metastatic breast cancer: a systematic literature review of real-world evidence studies

Background: This review aims to qualitatively summarize the published real-world evidence (RWE) for CDK4/6 inhibitors (CDK4/6i) approved for treating HR+, HER2-negative advanced/metastatic breast cancer (HR+/HER2- a/mBC). Materials & methods: A systematic literature review was conducted to identify RWE studies of CDK4/6i in HR+/HER2- a/mBC published from 2015 to 2019. Results: This review identified 114 studies, of which 85 were only presented at scientific conferences. Most RWE studies investigated palbociclib and demonstrated improved outcomes. There are limited long-term and comparative data between CDK4/6i and endocrine monotherapy, and within the CDK4/6i class. Conclusion: Available RWE suggests that CDK4/6i are associated with improved outcomes in HR+/HER2- a/mBC, although additional studies with longer follow-up periods are needed.

Adjuvant cyclin-dependent kinase 4/6 inhibition in hormone receptor-positive breast cancer: One Monarch to rule them all?

The use of cyclin-dependent kinase 4/6 (CDK4/6) inhibitors has dramatically improved outcomes for patients with metastatic, hormone receptor (HR)-positive breast cancer. Because of the continued high rate of relapse in patients with node-positive, HR-positive disease, evaluating these agents in the adjuvant setting is the logical next step. Three adjuvant CDK inhibitor trials have been reported to date, with only 1 of them showing a statistical advantage for the CDK inhibitor in comparison with endocrine therapy alone. These trials have key similarities and differences that could explain the disparate results. The one positive trial has a relatively short follow-up, and continued analysis is critical to confirm the benefit of adjuvant CDK inhibition in this setting. It is imperative that predictive biomarkers be determined so that these agents can be used in the patients most likely to benefit and thus the additional toxicity and expense can be avoided in those who do not require these agents. LAY SUMMARY: There is a critical need for new agents to prevent relapse in patients with hormone receptor-positive breast cancer. Trials to date evaluating cyclin-dependent kinase inhibitors, which decrease how quickly cancer cells multiply, have shown mixed results, with only 1 trial demonstrating that these agents decrease recurrence.

Endocrine therapy combined with targeted therapy in hormone receptor-positive metastatic breast cancer

Increasing numbers of targeted drugs are used in hormone receptor (HR)-positive metastatic breast cancer (MBC) to overcome or delay resistance to endocrine therapy. This study will systemically review the progress made in endocrine therapy combined with targeted therapy in the treatment of HR-positive MBC. From the “AI (aromatase inhibitor) era” represented by aromatase inhibitors, we have gradually entered the “post-AI era” represented by fulvestrant. Under the guidance of research on the molecular mechanism of endocrine therapy resistance, the “combination of endocrine therapy and targeted therapy” era is approaching. The development of drugs that target endocrine therapy resistance has concentrated on cyclin-dependent kinase 4/6 inhibitors, histone deacetylase inhibitors, and inhibitors of drug targets in the phosphatidylinositol 3 kinase-protein kinase B-mammalian target of rapamycin (PI3K-AKT-mTOR) pathway, providing new strategies for HR-positive MBC. Exploring biomarkers to guide the more precise use of targeted drugs in endocrine therapy for MBC is the focus of current and future research.

Prospects and challenges of anticancer agents' delivery via chitosan-based drug carriers to combat breast cancer: a review

Breast cancer (BC) is considered as one the most prevalent cancers worldwide. Due to its high resistance to chemotherapy and high probability of metastasis, BC is one of the leading causes of cancer-related deaths. The controlled release of chemotherapy drugs to the precise site of the tumor tissue will increase the therapeutic efficacy and decrease side effects of systemic administration. Among various drug delivery systems, natural polymers-based drug carriers have gained significant attention for cancer therapy. Chitosan, a natural polymer obtained by de-acetylation of chitin, holds huge potential for drug delivery applications because chitosan is non-toxic, non-immunogenic, biocompatible, chemically modifiable, and can be processed to form various formulations. In the current review, we will discuss the prospects and challenges of chitosan-based drug delivery systems in treating BC.

Advances in Therapy for Hormone Receptor (HR)-Positive, Human Epidermal Growth Factor Receptor 2 (HER2)-Negative Advanced Breast Cancer Patients Who Have Experienced Progression After Treatment with CDK4/6 Inhibitors

Approximately 70% of breast cancer (BC) cases are hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) BC. Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors have acted as star drugs for reversing endocrine therapy (ET) resistance and improving the prognosis of patients with HR+ advanced breast cancer (ABC) since they were initially approved. However, progression eventually occurs. In this review, we summarize the recent treatment strategies post CDK4/6 inhibitors: 1) CDK4/6 inhibitors plus exemestane and everolimus; 2) phosphoinositide-3-kinase (PI3K) inhibitor alpelisib plus fulvestrant for patients with PIK3CA mutation; 3) poly (ADP-ribose) polymerase (PARP) inhibitor for patients with germline PALB2 mutations, somatic BRCA1/2 mutations, or germline BRCA1/2 mutations; 4) exemestane and everolimus; and (5) chemotherapy. These strategies are all supported by evidence from clinical trials and retrospective studies. We also describe potential future treatment strategies post CDK4/6 inhibitors, such as the trophoblast cell surface antigen 2 (Trop-2) directed antibody–drug conjugate, cyclin-dependent kinase 7 (CDK7) inhibitors, and B-cell lymphoma-2 (BCL-2) inhibitors.

Efficacy and Safety of CDK4/6 Inhibitors Combined with Endocrine Therapy in HR+/HER-2- ABC Patients: A Systematic Review and Meta-Analysis

OBJECTIVE

To evaluate the efficacy and safety of cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors combined with endocrine therapy (ET) for hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER-2-) advanced breast cancer (ABC) patients.

METHODS

We searched clinical trials of CDK4/6 inhibitors combined with ET and calculated the clinical outcomes.

RESULTS

HR+/HER-2- ABC patients treated with CDK4/6 inhibitors combined with ET had significantly prolonged progression-free survival (PFS) and improved objective response rate (ORR) and clinical benefit rate (CBR).

CONCLUSIONS

CDK4/6 inhibitors combined with ET can bring more clinical benefits to ABC patients, and the safety profile is acceptable.

Pharmacokinetics, safety, activity, and biomarker analysis of palbociclib plus letrozole as first-line treatment for ER+/HER2- advanced breast cancer in Chinese women

PURPOSE

This phase 1, open-label, single-arm clinical trial evaluated pharmacokinetics, safety, and biomarker activity of palbociclib-letrozole as first-line treatment for estrogen receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer (ABC) in postmenopausal Chinese women to support palbociclib approval in China.

METHODS

Patients received palbociclib 125 mg once daily (3/1 schedule) plus letrozole 2.5 mg once daily. Blood samples were collected predose and ≤ 120 h after single and multiple doses of palbociclib. The incidence and severity of adverse events were reported. Skin biopsy tissues and blood samples were collected for biomarker assessments.

RESULTS

By 31 July 2018, 26 patients were enrolled. After single and multiple dosing, palbociclib maximum plasma concentration was 82.14 and 139.7 ng/mL, apparent clearance was 52.40 and 49.97 L/h, AUC_τ was 1217 and 2501 ng∙h/mL, and t_½ was 23.46 and 27.26 h, respectively. Levels of Ki67, retinoblastoma protein, and thymidine kinase decreased after palbociclib treatment. A similar safety profile as previously reported was observed.

CONCLUSIONS

Pharmacokinetic and pharmacodynamic effects of palbociclib were well characterized in Chinese patients with ABC. Despite higher exposure, pharmacokinetic parameters were similar to those of a previously studied non-Asian population. No palbociclib dose adjustment based on Chinese ethnicity is needed. Palbociclib-letrozole had a manageable safety profile.

CLINICAL TRIAL REGISTRATION

NCT02499146.

The EPICURE study: a pilot prospective cohort study of heterogeneous and massive data integration in metastatic breast cancer patients

BACKGROUND

Breast cancer is the most common cancer in women and the first cancer concerning mortality. Metastatic breast cancer remains a disease with a poor prognosis and about 30% of women diagnosed with an early stage will have a secondary progression. Metastatic breast cancer is an incurable disease despite significant therapeutic advances in both supportive cares and targeted specific therapies. In the management of a metastatic patient, each clinician follows a highly complex and strictly personal decision making process. It is based on a number of objective and subjective parameters which guides therapeutic choice in the most individualized or adapted manner.

METHODS/DESIGN

The main objective is to integrate massive and heterogeneous data concerning the patient's environment, personal and familial history, clinical and biological data, imaging, histological results (with multi-omics data), and microbiota analysis. These characteristics are multiple and in dynamic interaction overtime. With the help of mathematical units with biological competences and scientific collaborations, our project is to improve the comprehension of treatment response, based on health clinical and molecular heterogeneous big data investigation.

DISCUSSION

Our project is to prove feasibility of creation of a clinico-biological database prospectively by collecting epidemiological, socio-economic, clinical, biological, pathological, multi-omic data and to identify characteristics related to the overall survival status before treatment and within 15 years after treatment start from a cohort of 300 patients with a metastatic breast cancer treated in the institution.

TRIAL REGISTRATION

ClinicalTrials.gov identifier (NCT number): NCT03958136 . Registration 21st of May, 2019; retrospectively registered.

Targeting a novel LncRNA SNHG15/miR-451/c-Myc signaling cascade is effective to hamper the pathogenesis of breast cancer (BC) in vitro and in vivo

BACKGROUND

To our knowledge, LncRNA SNHG15 exerted its tumor-promoting effects to facilitate the development of breast cancer (BC), but there still needed more data to elucidate the potential underlying mechanisms.

METHODS

We examined genes expression status by performing Real-Time qPCR and Western Blot analysis, and cellular functions, including cell proliferation, viability, apoptosis, mobility, were measured by using the CCK-8 assay, colony formation assay, trypan blue staining assay, flow cytometer (FCM), transwell assay and wound scratch assay, respectively. The predicted targeting sites in LncRNA SNHG15, miR-451 and c-Myc 3'UTR were validated by dual-luciferase reporter gene system assay. Finally, we established the tumor-bearing mice models, and the expression status, including its enrichment and cellular localization were examined by immunohistochemistry (IHC) assay.

RESULTS

Our data indicated LncRNA SNHG15 upregulated c-Myc to facilitate BC progression by sponging miR-451 in a competing endogenous RNA (ceRNA)-dependent manner in vitro and in vivo. Specifically, LncRNA SNHG15 and c-Myc were upregulated, while miR-451 was downregulated in BC cells and clinical tissues, compared to their normal counterparts. In addition, miR-451 negatively correlated with LncRNA SNHG15 and c-Myc, and LncRNA SNHG15 was positively relevant to c-Myc in BC tissues. Next, we validated that LncRNA SNHG15 sponged miR-451 to upregulate c-Myc in BC cells. Further gain- and loss-of-function experiments evidenced that LncRNA SNHG15 promoted, while miR-451 inhibited malignant phenotypes, including cell proliferation, viability, migration, invasion and epithelial-mesenchymal transition (EMT) in BC cells. Interestingly, the inhibiting effects of LncRNA SNHG15 ablation on BC progression were abrogated by both silencing miR-451 and overexpressing c-Myc.

CONCLUSIONS

We concluded that targeting the LncRNA SNHG15/miR-451/c-Myc signaling cascade was novel to hamper BC progression, which broadened our knowledge in this field, and provided potential biomarkers for BC diagnosis and treatment.

Comparative effectiveness of first-line palbociclib plus letrozole versus letrozole alone for HR+/HER2- metastatic breast cancer in US real-world clinical practice

BACKGROUND

Findings from randomized clinical trials may have limited generalizability to patients treated in routine clinical practice. This study examined the effectiveness of first-line palbociclib plus letrozole versus letrozole alone on survival outcomes in patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor-negative (HER2-) metastatic breast cancer (MBC) treated in routine clinical practice in the USA.

PATIENTS AND METHODS

This was a retrospective observational analysis of electronic health records within the Flatiron Health Analytic Database. A total of 1430 patients with ≥ 3 months of follow-up received palbociclib plus letrozole or letrozole alone in the first-line setting between February 3, 2015, and February 28, 2019. Stabilized inverse probability treatment weighting (sIPTW) was used to balance baseline demographic and clinical characteristics. Real-world progression-free survival (rwPFS) and overall survival (OS) were analyzed.

RESULTS

After sIPTW adjustment, median follow-up was 24.2 months (interquartile range [IQR], 14.2-34.9) in the palbociclib group and 23.3 months (IQR, 12.7-34.3) in those taking letrozole alone. Palbociclib combination treatment was associated with significantly longer median rwPFS compared to letrozole alone (20.0 vs 11.9 months; hazard ratio [HR], 0.58; 95% CI, 0.49-0.69; P < 0.0001). Median OS was not reached in the palbociclib group and was 43.1 months with letrozole alone (HR, 0.66; 95% CI, 0.53-0.82; P = 0.0002). The 2-year OS rate was 78.3% in the palbociclib group and 68.0% with letrozole alone. A propensity score matching analysis showed similar results.

CONCLUSIONS

In this "real-world" population of patients with HR+/HER2- MBC, palbociclib in combination with endocrine therapy was associated with improved survival outcomes compared with patients treated with letrozole alone in the first-line setting.

TRIAL REGISTRATION

Clinicaltrials.gov; NCT04176354.

Breast Cancer Therapeutics and Biomarkers: Past, Present, and Future Approaches

Breast cancer (BC) is the leading cause of cancer death in women and the second-most common cancer. An estimated 281 550 new cases of invasive BC will be diagnosed in women in the United States, and about 43 600 will die during 2021. Continual research has shed light on all disease areas, including tumor classification and biomarkers for diagnosis/prognosis. As research investigations evolve, new classes of drugs are emerging with potential benefits in BC treatment that are covered in this manuscript. The initial sections present updated classification and terminology used for diagnosis and prognosis, which leads to the following topics, discussing the past and present treatments available for BC. Our review will generate interest in exploring the complexity of the cell cycle and its association with cancer biology as part of the plethora of target factors toward developing newer drugs and effective therapeutic management of BC.

Cyclin-dependent kinase inhibitors plus aromatase inhibitor in first-line treatment hormone-receptor-positive/HER2-negative advanced breast cancer women with or without visceral disease: time to turn page?

Breast cancer is the most common female tumour type and accounts for the leading cancer mortality in women worldwide. Up to 75% of breast cancers express the oestrogen receptor or progesterone receptor (hormone-receptor-positive). Aromatase inhibitors were the preferred first-line treatment option. New and acquired resistance to hormonal blockade has led to the development of targeted treatments. Cyclin-dependent kinases (CDKs) are a large family of serine-threonine kinases that play an important role in regulating cell cycle progression: palbociclib, ribociclib, and abemaciclib. We conducted a study to evaluate the efficacy of CDK inhibitors (CDKi) plus aromatase inhibitor in hormone-receptor-positive/HER2-negative ABC patients with visceral disease, postponing the use of chemotherapeutic agents and strengthening the power of endocrine agents. We enrolled 22 patients treated with CDKi (palbocilib) plus aromatase inhibitor (group A) and 38 patients treated with chemotherapy (group B). Our small study confirms the effectiveness of treatment with CDKi plus aromatase inhibitor, even in patients with visceral metastases, when compared with chemotherapy.

Signaling Pathways in Cancer: Therapeutic Targets, Combinatorial Treatments, and New Developments

Molecular alterations in cancer genes and associated signaling pathways are used to inform new treatments for precision medicine in cancer. Small molecule inhibitors and monoclonal antibodies directed at relevant cancer-related proteins have been instrumental in delivering successful treatments of some blood malignancies (e.g., imatinib with chronic myelogenous leukemia (CML)) and solid tumors (e.g., tamoxifen with ER positive breast cancer and trastuzumab for HER2-positive breast cancer). However, inherent limitations such as drug toxicity, as well as acquisition of de novo or acquired mechanisms of resistance, still cause treatment failure. Here we provide an up-to-date review of the successes and limitations of current targeted therapies for cancer treatment and highlight how recent technological advances have provided a new level of understanding of the molecular complexity underpinning resistance to cancer therapies. We also raise three basic questions concerning cancer drug discovery based on molecular markers and alterations of selected signaling pathways, and further discuss how combination therapies may become the preferable approach over monotherapy for cancer treatments. Finally, we consider novel therapeutic developments that may complement drug delivery and significantly improve clinical response and outcomes of cancer patients.

Supramolecular Self-Assembly Built by Weak Hydrogen, Chalcogen, and Unorthodox Nonbonded Motifs in 4-(4-Chlorophenyl)-3-[(4-fluorobenzyl)sulfanyl]-5-(thiophen-2-yl)-4H-1,2,4-triazole, a Selective COX-2 Inhibitor: Insights from X-ray and Theoretical Studies

A selective triazole-based COX-2 inhibitor, 4-(4-chlorophenyl)-3-[(4-fluorobenzyl)sulfanyl]-5-(thiophen-2-yl)-4H-1,2,4-triazole, C₁₉H₁₃ClFN₃S₂, has been synthesized, and its crystal structure was determined at 150 K. Single-crystal X-ray diffraction analysis revealed that the thiophene ring was disordered over two orientations. The crystal structure is stabilized by weak hydrogen and chalcogen bonds and unorthodox F···π and S···C(π) contacts. These noncovalent interactions cooperatively generate the supramolecular self-assembly in the crystalline state. The Hirshfeld surface and its associated two-dimensional (2D)-fingerprint plots were obtained to analyze the role of different noncovalent interactions in the crystal packing. Further, the enrichment ratio was obtained from different atom···atom pairs to calculate the propensity of these pairs to form noncovalent interactions. The strength of different dimeric motifs formed in the crystal structure and lattice energies was calculated by the PIXEL method. Furthermore, the topological analysis of the charge density of intermolecular interactions was described. A CSD survey of C–H···F hydrogen bond, C–S···Cl chalcogen bond, and unorthodox nonbonded contacts (F···π and S···C(π)) is presented. The title compound possesses selective inhibitory activity against human COX-2 enzyme rather than COX-1. The quantum mechanics (QM) polarized ligand docking analysis was used to predict the binding pose and study the title compound’s selectivity against COX-1/2 enzymes.

Can we cure oligometastatic disease? A practical point of view

PURPOSE OF REVIEW

To critically analyze the available evidence on oligometastatic breast cancer and to suggest therapeutic approaches for optimal management of these patients.

RECENT FINDINGS

Unlike metastatic breast cancer, which remains incurable, patients with a limited number and extent of metastatic lesions, that is, oligometastatic disease, might achieve disease control and long-term survival when radical therapy of the primary tumor, if present, and metastatic disease is added to standard systemic therapy. However, the lack of a clear definition, variety of presentations, and the absence of biomarkers makes oligometastatic breast cancer a poorly understood clinical entity for which there is no standard treatment.

SUMMARY

Improvements in systemic therapies along with radical treatment of the primary tumor and metastatic lesions, together with optimization in the use of imaging tools, may help to increase the percentage of patients with metastatic breast cancer who achieve no-evidence-of-disease status or, at least, chronification of the disease. However, the fundamental question remains: which patients may benefit the most from a radical therapeutic approach? In this article, we propose strategies for the appropriate selection and comprehensive management of these patients.

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.

Long-Term Pooled Safety Analysis of Palbociclib in Combination with Endocrine Therapy for Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative Advanced Breast Cancer: Updated Analysis with up to 5 Years of Follow-Up

Background

Previous studies demonstrated the tolerability of palbociclib plus endocrine therapy (ET). This analysis evaluated safety based on more recent cutoff dates and a longer palbociclib treatment exposure.

Patients and Methods

Data were pooled from three randomized studies of patients with hormone receptor‐positive/human epidermal growth factor receptor 2‐negative (HR+/HER2−) advanced breast cancer (ABC), including postmenopausal women who had not received prior systemic treatment for advanced disease (PALOMA‐1/‐2) and pre‐ and postmenopausal women who had progressed on prior ET (PALOMA‐3).

Results

Updated cutoff dates were December 21, 2017 (PALOMA‐1), May 31, 2017 (PALOMA‐2), and April 13, 2018 (PALOMA‐3). Total person‐years of treatment exposure were 1,421.6 with palbociclib plus ET (n = 872) and 528.4 with ET (n = 471). Any‐grade neutropenia and infections were more frequent with palbociclib plus ET (82.1% and 59.2%, respectively) than with ET (5.1% and 39.5%). The hazard ratios were 1.6 (p = .0995) for grade 3/4 infections, 1.8 (p = .4358) for grade 3/4 viral infections, 1.4 (p = .0001) for infections, and 30.8 (p < .0001) for neutropenia. Febrile neutropenia was reported in 1.4% of patients receiving palbociclib plus ET. Cumulative incidence of all‐grade hematologic adverse events in both arms peaked during the first year of treatment and plateaued over the 5 subsequent years. Interstitial lung disease was reported in 13 patients receiving palbociclib plus ET and 3 receiving ET.

Conclusion

This 5‐year, long‐term analysis demonstrated that palbociclib plus ET has a consistent and stable safety profile and is a safe treatment for patients with HR+/HER2− ABC.

Implications for Practice

Several treatments for patients with breast cancer are associated with long‐term or latent adverse events. This long‐term, 5‐year analysis demonstrated that palbociclib plus endocrine therapy has a consistent and stable safety profile without cumulative or delayed toxicities. These results further support palbociclib plus endocrine therapy as a safe and manageable treatment in clinical practice for patients with hormone receptor‐positive/human epidermal growth factor receptor 2‐negative advanced breast cancer.

This updated analysis based on data pooled from the three PALOMA studies is the largest long‐term analysis, to date, of the safety of a CDK4/6 inhibitor in combination with endocrine therapy for the treatment of advanced breast cancer.

CDK4/6 inhibitor plus endocrine therapy for hormone receptor-positive, HER2-negative metastatic breast cancer: The new standard of care

Patients presenting with hormone receptor-positive (HR⁺ ), human epidermal growth factor receptor 2-negative (HER2^- ) metastatic breast cancer (MBC) are usually treated with endocrine therapy (ET), except if there is a concern about endocrine resistance or a need to achieve rapid disease control due to visceral crisis. The combination of CDK4/6 inhibitor + ET has now replaced single-agent ET as the standard first-line treatment; and it can also be considered a standard option in the second-line setting. This review briefly summarizes recently reported efficacy findings from the key phase III clinical trials of CDK4/6 inhibitor + ET in patients with HR⁺ /HER2^- MBC, including evidence that adding a CDK4/6 inhibitor to ET improves overall survival and does so without reducing patients' quality of life. There is still much to learn regarding the use of CDK4/6 inhibitors and how they may be optimally integrated into clinical practice. In particular, there is a need for specific biomarkers that help predict the likelihood of response or resistance to CDK4/6 inhibitor therapy; and for data to guide treatment decisions when a patient's disease progresses on a CDK4/6 inhibitor.

Circulating tumor DNA dynamics in advanced breast cancer treated with CDK4/6 inhibition and endocrine therapy

Circulating tumor DNA (ctDNA) levels may predict response to anticancer drugs, including CDK4/6 inhibitors and endocrine therapy combinations (CDK4/6i+ET); however, critical questions remain unanswered such as which assay or statistical method to use. Here, we obtained paired plasma samples at baseline and week 4 in 45 consecutive patients with advanced breast cancer treated with CDK4/6i+ET. ctDNA was detected in 96% of cases using the 74-gene Guardant360 assay. A variant allele fraction ratio (VAFR) was calculated for each of the 79 detected mutations between both timepoints. Mean of all VAFRs (mVAFR) was computed for each patient. In our dataset, mVAFR was significantly associated with progression-free survival (PFS). Baseline VAF, on-treatment VAF or absolute changes in VAF were not associated with PFS, nor were CA-15.3 levels at baseline, week 4 or the CA-15.3 ratio. These findings demonstrate that ctDNA dynamics using a standardized multi-gene panel and a unique methodological approach predicts treatment outcome. Clinical trials in patients with an unfavorable ctDNA response are needed.

Patterns of treatment with everolimus exemestane in hormone receptor-positive HER2-negative metastatic breast cancer in the era of targeted therapy

BACKGROUND

There is currently no clinical trial data regarding the efficacy of everolimus exemestane (EE) following prior treatment with CDK4/6 inhibitors (CDK4/6i). This study assesses the use and efficacy of everolimus exemestane in patients with metastatic HR+ HER2- breast cancer previously treated with endocrine therapy (ET) or endocrine therapy + CDK4/6i.

METHODS

Retrospective analysis of electronic health record-derived data for HR+ HER2- metastatic breast cancer from 2012 to 2018. The proportion of patients receiving EE first-line, second-line, or third-line, and the median duration of EE prior to next line of treatment (TTNT) by line of therapy was calculated. OS for patients receiving EE first-line, second-line, or third-line, indexed to the date of first-line therapy initiation and stratified by prior treatment received, was calculated with Kaplan-Meier method with multivariable Cox proportional hazards regression analysis.

RESULTS

Six hundred twenty-two patients received EE first-line (n = 104, 16.7%), second-line (n = 273, 43.9%) or third-line (n = 245, 39.4%). Median TTNT was 8.3 months, 5.5 months, and 4.8 months respectively. Median TTNT of EE second-line was longer following prior ET alone compared to prior ET + CDK4/6i (6.2 months (95% CI 5.2, 7.3) vs 4.3 months (95% CI 3.2, 5.7) respectively, p = 0.03). Similarly, EE third-line following ET alone vs ET + CDK4/6i in first- or second-line resulted in median TTNT 5.6 months (95% CI 4.4, 6.9) vs 4.1 months (95% CI 3.6, 6.1) respectively, although this was not statistically significant (p = 0.08). Median OS was longer for patients who received EE following prior ET + CDK4/6i. EE second-line following ET + CDK 4/6i vs ET alone resulted in median OS 37.7 months vs. 32.7 months (p = 0.449). EE third-line following ET + CDK4/6i vs prior ET alone resulted in median OS 59.2 months vs. 40.8 months (p < 0.010). This difference in OS was not statistically significant when indexed to the start of EE therapy.

CONCLUSION

This study suggests that EE remains an effective treatment option after prior ET or ET + CDK4/6i use. Median TTNT of EE was longer for patients who received prior ET, whereas median OS was longer for patients who received prior ET + CDK4/6i. However, this improvement in OS was not statistically significant when indexed to the start of EE therapy suggesting that OS benefit is primarily driven by prior CDK4/6i use. EE remains an effective treatment option regardless of prior treatment option.

Real-life prognosis of 5041 bone-only metastatic breast cancer patients in the multicenter national observational ESME program

BACKGROUND

Bone-only (BO) metastatic breast cancer (MBC) is considered a more favorable entity than other MBC presentations. However, only few retrospective series and data from selected randomized controlled trials have been reported so far.

METHODS

Using the French national multicenter ESME (Epidemiological Strategy and Medico Economics) Data Platform, the primary objective of our study was to compare the overall survival (OS) of patients with BO versus non-BO MBC at diagnosis, with adjustment on main prognostic factors using a propensity score. Secondary objectives were to compare first-line progression-free survival (PFS1), describe treatment patterns, and estimate factors associated with OS.

RESULTS

Out of 20,095 eligible women, 5041 (22.4%) patients had BO disease [hormone-receptor positive (HR+)/human epidermal growth-factor-receptor-2 negative (HER2-), n = 4 102/13,229 (31%); HER2+, n = 644/3909 (16.5%); HR-/HER2-, n = 295/2 957 (10%)]. BO MBC patients had a better adjusted OS compared with non-BO MBC [52.1 months (95% confidence interval (CI) 50.3-54.1) versus 34.7 months (95% CI 34.0-35.6) respectively]. The 5-year OS rate of BO MBC patients was 43.4% (95% CI 41.7-45.2). They also had a better PFS1 [13.1 months (95% CI 12.6-13.8) versus 8.5 months (95% CI 8.3-8.7), respectively]. This observation could be repeated in all subtypes. BO disease was an independent prognostic factor of OS [hazard ratio 0.68 (95% CI 0.65-0.72), p < 0.0001]. Results were concordant in all analyses.

CONCLUSION

BO MBC patients have better outcomes compared with non-BO MBC, consistently, through all MBC subtypes.

Survival analysis of bevacizumab plus taxane treatment in luminal metastatic breast cancer

Background

The treatment of luminal metastatic breast cancer is based on endocrine therapy and chemotherapy treatment is limited to the progression of this treatment.

Materials & methods

We analyzed the efficacy of treatment with bevacizumab plus paclitaxel in 43 patients with hormone receptor-positive and HER2-negative metastatic breast cancer.

Discussion

Paclitaxel plus bevacizumab combination is a useful treatment in metastatic luminal breast cancer with an impressive overall survival of 31 months, similar to combination to endocrine therapy and targeted therapy in first line. In patients with hormone resistance, endocrine therapy saw worse results thus the taxol plus bevacizumab combination could be a better option. This combination does not influence the results of subsequent treatments; therefore, it could provide a good option for patients.

A prospective observational study of patient-reported functioning and quality of life in advanced and metastatic breast cancer utilizing a novel mobile application

Purpose

To assess and describe patient-reported outcomes (PROs) in women with locally advanced/unresectable or metastatic breast cancer (aBC/mBC) with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR + /HER2 −) status receiving palbociclib combination therapy in a US real-world setting.

Methods

A prospective, noninterventional, multicenter longitudinal study was conducted in US patients initiating treatment with palbociclib combination therapy for HR + /HER2 − aBC/mBC. PRO data (SF-12; CES-D-10; mood; pain; fatigue; interference of aBC/mBC or its treatment on family life, social life, physical activity, energy, and productivity; overall health rating; and quality of life [QOL]) were collected via a custom-developed mobile application at daily, weekly, and cycle-based intervals. Patient medical information (demographics, clinical characteristics, treatment information, and adverse events) was collected from medical records at baseline and at the end of the 6-month follow-up period.

Results

Patients’ general health status (SF-12) remained consistent throughout treatment and was generally consistent with published norms for individuals diagnosed with cancer. The presence of depression (CES-D-10) was low and did not change substantially over time. Mean pain and fatigue scores using an 11-point numeric rating scale were low and remained stable. Patients, on average, reported neutral or positive moods. Patient-reported QOL and overall health was primarily “Good,” “Very good,” or “Excellent.” Findings were consistent regardless of patient experience with neutropenia.

Conclusions

Patients treated with palbociclib, on average, reported consistently low levels of pain and fatigue as well as good QOL and overall health that remained stable throughout the first 6 months of treatment regardless of episodes of neutropenia.

Supplementary information

The online version of this article (10.1007/s10549-020-06082-7) contains supplementary material, which is available to authorized users.

Clinical Challenges in the Management of Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Metastatic Breast Cancer: A Literature Review

Endocrine therapy (ET) is integral to the treatment of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC). Aromatase inhibitors (AIs; e.g., anastrozole, letrozole, exemestane), selective estrogen receptor modulators (e.g., tamoxifen), and the selective estrogen receptor degrader, fulvestrant, inhibit tumor cell proliferation by targeting ER signaling. However, the efficacy of ET could be limited by intrinsic and acquired resistance mechanisms, which has prompted the development of targeted agents and combination strategies. In recent years, the treatment landscape for HR+, HER2- MBC has evolved rapidly. AIs, historically the first-line treatment for postmenopausal patients with HR+, HER2- MBC, have been challenged by more effective ET, such as fulvestrant alone or in combination with an AI, and the cyclin-dependent kinase (CDK)4/6 inhibitors, which have increasingly become the new standard of care. For endocrine-resistant disease (≥ second-line), clinical trials demonstrated that the mammalian target of rapamycin inhibitor, everolimus, enhanced the efficacy of exemestane or fulvestrant after progression on an AI. CDK4/6 inhibitors in combination with fulvestrant have demonstrated superior progression-free survival and overall survival versus fulvestrant alone. Recently, the combination of fulvestrant with alpelisib in phosphatidylinositol-4,5-bisphosphate 3-kinase (PIK3CA) mutated HR+, HER2- MBC following progression on or after ET was approved, based on the SOLAR-1 study. However, the optimal sequencing of treatments is unknown, especially following disease progression on a CDK4/6 inhibitor. This review aims to provide practical guidance for the management of HR+, HER2- MBC based on available data and the utility of genomic biomarkers, including germline breast cancer genes 1 and 2 (BRCA1/2) mutations, and somatic estrogen receptor alpha gene (ESR1), HER2, and PIK3CA mutations.

Cyclin Pathway Genomic Alterations Across 190,247 Solid Tumors: Leveraging Large-Scale Data to Inform Therapeutic Directions

BACKGROUND

We describe the landscape of cyclin and interactive gene pathway alterations in 190,247 solid tumors.

METHODS

Using comprehensive genomic profiling (315 genes, >500× coverage), samples were analyzed for alterations in activating/sensitizing cyclin genes (CDK4 amplification, CDK6 amplification, CCND1, CCND2, CCND3, CDKN2B [loss], CDKN2A [loss], SMARCB1), hormone genes (estrogen receptor 1 [ESR1], androgen receptor [AR]), and co-alterations in genes leading to cyclin inhibitor therapeutic resistance (RB1 and CCNE1).

RESULTS

Alterations in at least one cyclin activating/sensitizing gene occurred in 24% of malignancies. Tumors that frequently harbored at least one cyclin alteration were brain gliomas (47.1%), esophageal (40.3%) and bladder cancer (37.9%), and mesotheliomas (37.9%). The most frequent alterations included CDKN2A (13.9%) and CDKN2B loss (12.5%). Examples of unique patterns of alterations included CCND1 amplification in breast cancer (17.3%); CDK4 alterations in sarcomas (12%); CCND2 in testicular cancer (23.4%), and SMARCB1 mutations in kidney cancer (3% overall, 90% in malignant rhabdoid tumors). Alterations in resistance genes RB1 and CCNE1 affected 7.2% and 3.6% of samples. Co-occurrence analysis demonstrated a lower likelihood of concomitant versus isolated alterations in cyclin activating/sensitizing and resistance genes (odds ratio [OR], 0.35; p < .001), except in colorectal, cervical, and small intestine cancers. AR and cyclin activating/sensitizing alterations in prostate cancer co-occurred more frequently (vs. AR alterations and wild-type cyclin activating/sensitizing alterations) (OR, 1.79; p < .001) as did ESR1 and cyclin activating/sensitizing alterations in breast (OR, 1.62; p < .001) and cervical cancer (OR, 4.08; p = .04) (vs. ESR1 and cyclin wild-type activating/sensitizing alterations).

CONCLUSION

Cyclin pathway alterations vary according to tumor type/histology, informing opportunities for targeted therapy, including for rare cancers.

IMPLICATIONS FOR PRACTICE

Cyclin pathway genomic abnormalities are frequent in human solid tumors, with substantial variation according to tumor site and histology. Opportunities for targeted therapy emerge with comprehensive profiling of this pathway.

Real-World Outcomes of Treating Advanced Breast Cancer Patients With Palbociclib: A Multicenter Retrospective Cohort Study in Japan-The KBCOG-14 Study

Background

Clinical studies have shown that palbociclib improves progression-free survival in hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) patients with advanced breast cancer (ABC). However, there are insufficient data on its use in a real-world setting in Japan. The aim of this study was to investigate the effectiveness, predictive factors, and safety of palbociclib among Japanese patients in routine clinical practice.

Methods

Between December 1, 2017, and April 30, 2019, we recruited patients from 9 hospitals and retrospectively evaluated the data on HR+/HER2- patients with ABC who received palbociclib for at least 1 week. The correlation between time-to-treatment discontinuation (TTD) and clinical background was investigated via univariate and multivariate analyses using Cox hazards models.

Results

A total of 177 women were available for analysis. Of these patients, 58 (33%) patients were treated with palbociclib with an aromatase inhibitor and 117 (66%) patients were treated with palbociclib and a selective estrogen receptor degrader. Approximately three-fourths of the patients (n = 130, 73%) received palbociclib as third- or later-line therapy. One-third of the patients had 3 or more metastatic sites (n = 59, 33%), and one-third of the patients had liver metastasis (n = 59, 33%). The median follow-up duration at the time of data cutoff was 8.9 months, the median TTD was 6.3 months, and the median overall survival was not reached. Liver metastasis (hazard ratio [HR]: 1.54 [95% confidence interval {CI}: 1.03-2.27]), high serum lactate dehydrogenase (LDH) level (>300 U/L) (HR: 2.58 [95% CI: 1.49-4.26]), and high neutrophil-to-lymphocyte ratio (NLR) (⩾3.0) (HR: 1.76 [95% CI: 1.13-2.69]) were significantly associated with shorter TTD. The most common hematologic adverse event was neutropenia, which occurred in 93% of the patients.

Conclusion

Based on the results of the pivotal phase 3 trials, the median TTD recorded in this study was shorter than expected. Our results suggest that liver metastasis, serum LDH level, and NLR may be predictive factors for HR+/HER2- ABC treatment outcomes.

Palbociclib Plus Fulvestrant or Everolimus Plus Exemestane for Pretreated Advanced Breast Cancer with Lobular Histotype in ER+/HER2- Patients: A Propensity Score-Matched Analysis of a Multicenter Retrospective Patient Series

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) in combination with endocrine therapy (ET) show meaningful efficacy and tolerability in patients with metastatic breast cancer (MBC), but the optimal sequence of ET has not been established. It is not clear if patients with lobular breast carcinomas (LBC) derive the same benefits when receiving second line CDK4/6i. This retrospective study compared the efficacy of palbociclib plus fulvestrant (PALBO–FUL) with everolimus plus exemestane (EVE–EXE) as second-line ET for hormone-resistant metastatic LBC. From 2013 to 2018, patients with metastatic LBC positivity for estrogen and/or progesterone receptors and HER2/neu negativity, who had relapsed during adjuvant hormonal therapy or first-line hormonal treatment, were enrolled from six centers in Italy in this retrospective study. A total of 74 out of 376 patients (48 treated with PALBO–FUL and 26 with EVE–EXE) with metastatic LBC were eligible for inclusion. Progression-free survival (PFS) was longer in patients receiving EVE–EXE compared with PALBO–FUL (6.1 vs. 4.5 months, univariate HR 0.58, 95% CI 0.35–0.96; p = 0.025). On the propensity score (PS) analysis, PFS was confirmed to be significantly longer for patients treated with EVE–EXE compared to PALBO–FUL (6.0 vs. 4.6 months, p = 0.04). This retrospective analysis suggests that EVE–EXE is more effective than PALBO–FUL for second line ET of metastatic LBC, allowing us to speculate on the optimal therapeutic sequence.

CDK4/6 inhibitors in breast cancer: differences in toxicity profiles and impact on agent choice. A systematic review and meta-analysis

Introduction: CDK4/6 inhibitor approval for hormone-responsive breast tumors has significantly changed therapeutic algorithms, with three drugs currently approved.Areas covered: Here, we analyze the toxicity profiles of palbociclib, ribociclib, and abemaciclib through a systematic review and meta-analysis. Palbociclib and ribociclib showed high rates of hematological toxicity, primarily neutropenia, and were associated with a low rate of severe infections. Abemaciclib was associated with a high rate of gastrointestinal toxicities, primarily diarrhea, of grade 1-2 in most cases. Ribociclib was associated with a high rate of hepatic, and respiratory toxicity and with QTc prolongation. The toxicity rate of ribociclib was higher in metastatic patients than non-metastatic patients, with approximately 33% more grade 3-4 toxicities and 21% more grade 3-4 neutropenic events. A 5% higher risk of diarrhea was observed in postmenopausal patients. Pre-treated patients did not show a higher toxicity rate for palbociclib/ribociclib than previously untreated patients, while a 26% higher risk of any grade neutropenia and 6% higher risk of grade 3-4 diarrhea were observed with abemaciclib.Expert opinion: Considering the similar efficacies and indications of palbociclib, ribociclib, and abemaciclib, the evaluation of their toxicity profiles may facilitate treatment choice.

Inclusion of non-inferiority analysis in superiority-based clinical trials with single-arm, two-stage Simon's design

INTRODUCTION

Non-inferiority (NI) analysis is not usually considered in the early phases of clinical development. In some negative phase II trials, a post-hoc NI analysis justified additional phase III trials that were successful. However, the risk of false positive achievements was not controlled in these early phase analyses. We propose to preplan NI analyses in superiority-based Simon's two-stage designs to control type I and II error rates.

METHODS

Simulations have been proposed to assess the control of type I and II errors rates with this method. A total of 12,768 two-stage Simon's design trials were constructed based on different assumptions of rejection response probability, desired response probability, type I and II errors, and NI margins. P-value and type II error were calculated with stochastic ordering using Uniformly Minimum Variance Unbiased Estimator. Type I and II errors were simulated using the Monte Carlo method. The agreement between calculated and simulated values was analyzed with Bland-Altman plots.

RESULTS

We observed the same level of agreement between calculated and simulated type I and II errors from both two-stage Simon's superiority designs and designs in which NI analysis was allowed. Different examples has been proposed to explain the utility of this method.

CONCLUSION

Inclusion of NI analysis in superiority-based single-arm clinical trials may be useful for weighing additional factors such as safety, pharmacokinetics, pharmacodynamic, and biomarker data while assessing early efficacy. Implementation of this strategy can be achieved through simple adaptations to existing designs for one-arm phase II clinical trials.

Testing the low dose mixtures hypothesis from the Halifax project

In 2013, 60 scientists, representing a larger group of 174 scientists from 26 nations, met in Halifax, Nova Scotia to consider whether - using published research - it was logical to anticipate that a mixture of chemicals, each thought to be non-carcinogenic, might act together in that mixture as a virtual carcinogen. The group identified 89 such chemicals, each one affecting one or more Hallmark(s) - collectively covering all Hallmarks of Cancer - confirming the possibility that a chemical mixture could induce all the Hallmarks and function as a virtual carcinogen, thereby supporting the concern that chemical safety research that does not evaluate mixtures, is incomplete. Based on these observations, the Halifax Project developed the Low-Dose Carcinogenesis Hypothesis which posits "…that low-dose exposures to [mixtures of] disruptive chemicals that are not individually carcinogenic may be capable of instigating and/or enabling carcinogenesis." Although testing all possible combinations of over 80,000 chemicals of commerce would be impractical, prudence requires designing a methodology to test whether low-dose chemical mixtures might be carcinogenic. As an initial step toward testing this hypothesis, we conducted a mini review of published empirical observations of biological exposures to chemical mixtures to assess what empirical data exists on which to base future research. We reviewed studies on chemical mixtures with the criteria that the studies reported both different concentrations of chemicals and mixtures composed of different chemicals. We found a paucity of research on this important question. The majority of studies reported hormone related processes and used chemical concentrations selected to facilitate studying how mixtures behave in experiments that were often removed from clinical relevance, i.e., chemicals were not studied at human-relevant concentrations. New research programs must be envisioned to enable study of how mixtures of small doses of chemicals affect human health, starting, when at all possible, from non-malignant specimens when studies are done in vitro. This research should use human relevant concentrations of chemicals, expand research beyond the historic focus on endocrine endpoints and endocrine related cancers, and specifically seek effects that arise uniquely from exposure to chemical mixtures at human-relevant concentrations.

Therapy Algorithms for the Diagnosis and Treatment of Patients with Early and Advanced Breast Cancer

Background

In order to offer optimal treatment approaches based on available evidence, the Commission Breast of the Working Group Gynecologic Oncology (AGO) of the German Cancer Society developed therapy algorithms for eight complex treatment situations in primary and advanced breast cancer.

Summary

Therapy algorithms for the following complex treatment situations are outlined in this paper: (neo)adjuvant therapy of human epidermal growth factor receptor 2 (HER2)-positive breast cancer; axillary surgery and neoadjuvant chemotherapy; adjuvant endocrine therapy in premenopausal patients; adjuvant endocrine therapy in postmenopausal patients; hormone receptor (HR)-positive/HER2-negative metastatic breast cancer: strategies; HR-positive/HER2-negative metastatic breast cancer: endocrine-based first-line treatment; HER2-positive metastatic breast cancer: first to third-line; metastatic triple-negative breast cancer.

Key Messages

The therapy options shown in these algorithms are based on the current AGO recommendations updated in January 2020 but cannot represent all evidence-based treatment options. Prior therapies, performance status, comorbidities, patient preference, etc. must be taken into account for the actual treatment choice. Therefore, in individual cases, other evidence-based treatment options not listed here may also be appropriate and justified.

Opportunities for Antigen Discovery in Metastatic Breast Cancer

Immune checkpoint inhibitor-based immunotherapy (ICI) of breast cancer is currently efficacious in a fraction of triple negative breast cancers (TNBC) as these cancers generally carry high tumor mutation burden (TMB) and show increased tumor infiltration by CD8+ T cells. However, most estrogen receptor positive breast cancers (ERBC) have low TMB and/or are infiltrated with immunosuppressive regulatory T cells (Tregs) and thus fail to induce a significant anti-tumor immune response. Our understanding of the immune underpinning of the anti-tumor effects of CDK4/6 inhibitor (CDKi) treatment coupled with new knowledge about the mechanisms of tolerance to self-antigens suggests a way forward, specifically via characterizing and exploiting the repertoire of tumor antigens expressed by metastatic ERBC. These treatment-associated tumor antigens (TATA) may include the conventional tumor neoantigens (TNA) encoded by single nucleotide mutations, TNA encoded by tumor specific aberrant RNA transcription, splicing and DNA replication induced frameshift (FS) events as well as the shared tumor antigens. The latter may include the conventional tumor associated antigens (TAA), cancer-testis antigens (CTA) and antigens encoded by the endogenous retroviral (ERV) like sequences and repetitive DNA sequences induced by ET and CDKi treatment. An approach to identifying these antigens is outlined as this will support the development of a multi-antigen-based immunotherapy strategy for improved targeting of metastatic disease with potential for minimal autoimmune toxicity against normal tissues.

Cost-effectiveness of ribociclib as initial treatment for premenopausal women with advanced breast cancer in Singapore

BACKGROUND

CDK4/6 inhibitors have shown promising results for treating advanced breast cancer (ABC) and are routinely used in Singapore. In view of their high costs, it is important to assess their relative value compared to existing standards of care in the local setting.

AIMS

This study evaluates the cost-effectiveness of adding ribociclib to goserelin and a nonsteroidal aromatase inhibitor or tamoxifen as initial therapy for premenopausal women with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) ABC in Singapore.

METHODS

A partitioned survival model with four health states (progression-free on first-line treatment, progression-free on second-line treatment, progressed disease, and death) was developed from a healthcare system perspective over a 10-year time horizon. Key clinical inputs were derived from the MONALEESA-7 trial, and survival curves were extrapolated beyond the trial period. Health state utilities were derived from the literature and direct medical costs were obtained from local public healthcare institutions. A discount rate of 3% was applied to both costs and outcomes. One-way deterministic and probabilistic sensitivity analyses were conducted to explore uncertainties.

RESULTS

The base-case analysis resulted in an incremental cost-effectiveness ratio (ICER) of SGD197, 667 per quality-adjusted life-year. Sensitivity analyses showed that the ICER was sensitive to the survival parametric distribution, ribociclib price, time horizon, and utility weights used. Even when these were varied, ICERs remained high and not cost-effective in the local context.

CONCLUSION

At its current price, adding ribociclib to endocrine therapy is unlikely to be cost-effective in Singapore for HR+, HER2- ABC. Results from this study are useful to inform future funding decisions for CDK4/6 inhibitors alongside other factors including clinical effectiveness, safety, and budget impact considerations.

Analysis of subsequent therapy in Japanese patients with hormone receptor‒positive/human epidermal growth factor receptor 2‒negative advanced breast cancer who received palbociclib plus endocrine therapy in PALOMA-2 and -3

BACKGROUND

In the double-blind, phase 3 PALOMA-2 and PALOMA-3 studies, palbociclib plus endocrine therapy (ET) demonstrated significant improvement in progression-free survival versus placebo plus ET in patients with hormone receptor‒positive/human epidermal growth factor receptor 2‒negative advanced breast cancer. This analysis assessed subsequent treatment patterns after palbociclib therapy in Japanese patients enrolled in the PALOMA-2 and PALOMA-3 studies.

METHODS

PALOMA-2 included postmenopausal women who had not received prior systemic therapy for advanced disease. PALOMA-3 included pre- or postmenopausal women who had progressed on previous ET. Types of subsequent therapy were assessed, and treatment durations of subsequent therapy were estimated using the Kaplan-Meier method.

RESULTS

Japanese patients were enrolled in PALOMA-2 (n = 46) and PALOMA-3 (n = 35). In both studies, the most common first subsequent therapy was ET (PALOMA-2, 77% in the palbociclib group and 75% in the placebo group; PALOMA-3, 55% and 43%, respectively), followed by chemotherapy (PALOMA-2, 18% and 8%; PALOMA-3, 32% and 57%). The median (95% CI) duration of first subsequent therapy was 6.4 (2.3‒13.9) months with palbociclib plus letrozole and 6.7 (2.8‒13.0) months with placebo plus letrozole in PALOMA-2 and 3.8 (2.4‒5.7) months with palbociclib plus fulvestrant and 9.7 (1.0‒not estimable) months with placebo plus fulvestrant in PALOMA-3.

CONCLUSIONS

The types of first subsequent therapy received by Japanese patients in the palbociclib plus ET and placebo plus ET groups were similar. Further evaluation of subsequent therapy data in the real-world setting is warranted considering the small sample size of this analysis.