Delaying Chemotherapy in the Treatment of Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Advanced Breast Cancer

Real-World Analysis of Clinical and Demographic Characteristics, Treatment Patterns, and Outcomes in Predominantly Older Patients with HR+/HER2- Metastatic Breast Cancer Receiving Abemaciclib in Routine Clinical Practice

INTRODUCTION

Hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) is the most frequently diagnosed metastatic breast cancer (mBC) subtype. Combinations of endocrine therapy (ET) with cyclin-dependent kinase 4/6 inhibitors (CDK4 & 6is) improve outcomes compared with ET alone. The efficacy and safety of abemaciclib among patients with HR+/HER2- mBC has been demonstrated in the MONARCH clinical trials; however, there is a paucity of real-world evidence, particularly in older patients.

METHODS AND MATERIALS

This retrospective cohort study analyzed the electronic medical record data/charts of adult patients with HR+/HER2- mBC receiving abemaciclib in US-based community oncology settings (1 September 2017 to 30 September 2019). Patients with other primary malignancies, clinical trial enrollment, and incomplete charts were excluded. Patient characteristics, treatment attributes and patterns, and real-world outcomes (clinical benefit rate [CBR] and stable disease among patients with response data available, time to chemotherapy [TTC], time to treatment discontinuation [TTD], and progression-free survival [PFS]) were summarized. Multivariable models evaluated the association between demographic/clinical characteristics and outcomes.

RESULTS

Of the 448 final patients, 99% were female, with a median age of 67 years (25% were ≥ 75 years) and median follow-up of 11 months; most (60%) initiated abemaciclib within 2 years of mBC diagnosis. Patients received a median of 1 (P25 = 0, P75 = 3) prior line of therapy for mBC before abemaciclib, including other CDK4 & 6is (48%) and prior chemotherapy (31%); most (57%) had visceral disease. The CBR for the overall population was 53%, with 48% achieving stable disease. The median TTC was not reached; median TTD was 249 days (95% confidence interval [CI]: 202, 304). The median PFS was 329 days (95% CI 266, 386). The discontinuation rate of abemaciclib owing to adverse events (30%) trended higher with age (years) (P = 0.027): 18-49 (n = 42; 19%), 50-64 (n = 155; 25%), 65-74 (n = 138; 32%), 75-84 (n = 82; 37%), ≥ 85 (n = 31; 49%); only 23% of patients overall had a dose hold or reduction prior to discontinuation.

CONCLUSIONS

These patients were older than those in the MONARCH studies with substantial visceral disease, and prior chemotherapy and CDK4 & 6i use. Discontinuation rates were higher than in previous real-world studies (11.9%), highlighting the need for proactive management to optimize outcomes, particularly in older patients with mBC.

Impact of CDK4/6 inhibitors on chemotherapy utilization in earlier therapy lines for HR+/HER2- metastatic breast cancer in the United States

PURPOSE

Delaying chemotherapy remains a vital goal in therapeutic management of HR+/HER2- metastatic breast cancer (MBC). However, recent reports continue to highlight substantially high chemotherapy utilization in earlier therapy lines. In this study, we explored the impact of cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor therapy class, introduced in 2015, on early chemotherapy utilization in an older population of patients with HR+/HER2- MBC in the United States (US).

METHODS

Using an interrupted time series design, patients with a confirmed diagnosis of MBC aged ≥ 65 years initiating systemic therapy during 2010-2019 were selected from the SEER-Medicare database. The proportion of chemotherapy use was summarized quarterly based on the date of treatment initiation separately in the first, second, and third lines. Segmented regression models adjusted for autocorrelation over time were fitted to estimate trends before and after the availability of CDK4/6 inhibitors in the first quarter of 2015.

RESULTS

Of the 3244 eligible women (median age at diagnosis: 74 years), all initiated first-line therapy; 47.9% (n = 1581) initiated second-line therapy, and 50.1% (n = 792) initiated third-line therapy. Overall utilization of chemotherapy (alone or in combination) during the study period was 15.7% for the first line, 19.6% for the second line, and 24.8% for the third line. Chemotherapy utilization in the period immediately after introduction of CDK4/6 inhibitor therapy decline by estimated 2.5% in the first line (P = 0.408), 15.5% in the second line (P = 0.005), and 16.3% in the third line (P = 0.003).

CONCLUSIONS

This population-based study illustrates that chemotherapy utilization in earlier therapy lines for HR+/HER2- MBC declined steadily between 2010 and 2019. These declines were significantly accelerated by the introduction of CDK4/6 therapy class in 2015, notably in the second- and third-line settings.

Using qualitative interviews to identify patient-reported clinical trial endpoints and analyses that are the most meaningful to patients with advanced breast cancer

BACKGROUND

Designing clinical trials with the emphasis on the patient-centered approach and focusing on clinical outcomes that are meaningful to patients is viewed as a priority by drug developers, regulatory agencies, payers, clinicians, and patients. This study aimed to capture information on clinical trial endpoints that would be most important and relevant for patients with advanced breast cancer, based on patient-reported outcomes.

METHODS

Patients with either advanced triple-negative breast cancer [TNBC] and a maximum of two lines of systemic therapy or hormone receptor-positive/human epidermal growth factor receptor 2-negative [HR+/HER2-] breast cancer and a maximum of three lines of systemic therapy, participated in semi-structured concept elicitation interviews. Concept saturation was assessed. A sign, symptom, or impact was defined as "salient" if mentioned by ≥ 60% of participants, with an average bother rating of ≥ 5 (0-10 Scale). Participants were also asked about treatment priorities and to evaluate hypothetical scenarios showing different health-related functioning and quality-of-life treatment outcomes, using graphical representations.

RESULTS

Thirty-two participants (97% women; aged 29+ years) with TNBC (n = 17) or HR+/HER2- breast cancer (n = 15) provided generally similar reports on symptom experience, with fatigue and pain being most salient, though importance of certain treatment-related symptoms varied between the two groups. Patients reported consistent perspectives on the importance of treatment outcomes: when considering a new treatment, they prioritized efficacy of the therapy, acceptable tolerability, stability, predictability of symptoms over time, and the duration of preserved health-related quality of life and physical functioning. The meaningful difference in preserved physical functioning was 2-3 months for 46% of participants with TNBC, whereas for most participants with HR+/HER2- breast cancer it started from 6-7 months. Both groups of participants found it easier to accept some toxicity at the beginning of therapy if it was followed by improvement, as opposed to improvement followed by deterioration.

CONCLUSION

The results may help to inform the design of patient-centered clinical trials, to interpret health-related quality of life and/or patient-reported outcomes, and to optimize care for patients with advanced breast cancer.

Cost-effectiveness of ribociclib versus palbociclib in combination with an aromatase inhibitor as first-line treatment of postmenopausal women with HR+/HER2- advanced breast cancer: analysis based on final OS results of MONALEESA-2 and PALOMA-2

BACKGROUND AND AIMS

Combination of a cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor and an aromatase inhibitor is the standard of care first-line (1L) treatment of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC). Updated clinical data have become available from the MONALEESA-2 and PALOMA-2 trials for ribociclib and palbociclib, respectively. This analysis with updated data assessed the cost-effectiveness of ribociclib versus palbociclib, both in combination with letrozole, in the setting of 1L therapy of postmenopausal women with HR+/HER2- ABC, from a United Kingdom (UK) National Health Service perspective.

METHODS

A three state (progression-free, progressed disease, and death) partitioned survival model with a 1-month cycle was developed. Clinical data were derived from MONALEESA-2 (NCT01958021) and PALOMA-2 (NCT01740427). The treatment effect was modeled using hazard ratios (HRs) for progression-free survival and overall survival derived through a matched-adjusted indirect comparison. Trial data and published literature were used to derive utility values. Cost inputs included drug acquisition, disease monitoring, subsequent therapies, and adverse events. Costs and outcomes were discounted by 3.5%, over a 40-year lifetime horizon. One-way and probabilistic sensitivity analyses were performed.

RESULTS

Ribociclib dominated palbociclib, and was both overall cost saving (-£3,273) and more effective (+1.251 quality-adjusted life years [QALYs]). Ribociclib total drug costs were £17,156 lower than palbociclib. At a £30,000 per QALY willingness-to-pay threshold, the probability of ribociclib being cost-effective was almost 100%. Ribociclib remained cost-effective when varying HRs, utilities, drug cost, and health state costs.

CONCLUSIONS

Ribociclib is both cost-saving and cost-effective compared with palbociclib for the 1L treatment of postmenopausal women with HR+/HER2- ABC in the UK.

Safety and efficacy of ribociclib plus letrozole in patients with HR+, HER2- advanced breast cancer: Results from the Spanish sub-population of the phase 3b CompLEEment-1 trial

BACKGROUND

Breast cancer is the most common malignancy and the second leading cause of cancer-related mortality in Spanish women. Ribociclib in combination with endocrine therapy (ET) has shown superiority in prolonging survival in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) vs. ET alone.

METHODS

CompLEEment-1 is a single-arm, open-label phase 3b trial evaluating ribociclib plus letrozole in a broad population of patients with HR+, HER2- ABC. The primary endpoints were safety and tolerability. Here we report data for Spanish patients enrolled in CompLEEment-1.

RESULTS

A total of 526 patients were evaluated (median follow-up: 26.97 months). Baseline characteristics showed a diverse population with a median age of 54 years. At study entry, 56.5% of patients had visceral metastases and 8.7% had received prior chemotherapy for advanced disease. Rates of all-grade and Grade ≥3 adverse events (AEs) were 99.0% and 76.2%, respectively; 21.3% of patients experienced a serious AE, and 15.8% of AEs led to treatment discontinuation. AEs of special interest of neutropenia, increased alanine aminotransferase, increased aspartate aminotransferase and QTcF prolongation occurred in 77.8%, 14.8%, 11.4% and 4.0% of patients, respectively. Patients aged >70 years experienced increased rates of all-grade and Grade ≥3 neutropenia and anemia. Efficacy results were consistent with the global study.

CONCLUSIONS

Results from Spanish patients enrolled in CompLEEment-1 are consistent with global data showing efficacy and a manageable safety profile for ribociclib plus letrozole treatment in patients with HR+, HER2- ABC, including populations of interest (NCT02941926).

TRIAL REGISTRATION

ClinicalTrials.gov NCT02941926.

Real-World Patient Characteristics, Utilization Patterns, and Outcomes of US Patients with HR+, HER2- Metastatic Breast Cancer Treated with Abemaciclib

BACKGROUND

Abemaciclib is the most recent oral cyclin-dependent kinase 4 and 6 inhibitor (CDK4 & 6i) to receive US Food and Drug Administration (FDA) approval to treat hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced or metastatic breast cancer (MBC). Administrative claims data were used to describe patient characteristics and select clinical and economic outcomes in US patients treated in routine clinical practice. Prior analyses from electronic health records data indicate approximately 25% of patients received either palbociclib or ribociclib for MBC before initiating abemaciclib treatment; this work further explored these findings and associated outcomes.

METHODS

This retrospective study analyzed medical and pharmacy claims from the IBM^® MarketScan^® Research Databases between 1 January 2007 to 31 January 2020. Patients with HR+, HER2- MBC newly initiating abemaciclib between 1 September 2017 and 31 October 2019 were included and grouped by concomitant therapy (+aromatase inhibitor (AI), +fulvestrant (F), 200 mg abemaciclib monotherapy (Mono), or +other), and outcomes were analyzed by prior CDK4 & 6i use. Patient and treatment characteristics were summarized with descriptive statistics. Kaplan-Meier methods assessed time-to-discontinuation (TTD; i.e., persistency) and time-to-chemotherapy (TTC). Adherence (defined by the medication possession ratio) and drug wastage were determined.

RESULTS

This analysis included 454 patients (mean age 57.7 years), with 35.0% (n = 159) in the +F group, 29.3% (n = 133) in the +AI group, 10.4% (n = 47) in the 200 mg Mono group, and 25.3% (n = 115) in the +other group. Prior chemotherapy and CDK 4 & 6i use were present in 23.8% and 49.8% of all patients, respectively. Visceral metastases were present at abemaciclib initiation in 50.4% in the +AI group; 49.7% in the +F group; and 55.3% in the 200 mg Mono group. Liver metastases were present in 33.7% of the overall population. Among patients without prior CDK4 & 6i use, the median TTD for patients receiving abemaciclib + AI was not reached [95% CI 430-not reached (NR) days], abemaciclib + F [531 days (95% CI 281-NR)], and abemaciclib mono [141 days (95% CI 80-NR)]. Median TTC for abemaciclib + AI and abemaciclib + F groups were not reached and the median TTC for abemaciclib mono was 535 days (95% CI 181-NR). Medication adherence was 88.7% and medication wastage costs among those with at least one dose modification were $808.12 and $452.2 per patient per month based on amount paid and wholesale acquisition cost (WAC), respectively. Mean length of follow-up for all patients was 350 days (SD 187).

CONCLUSION

These real-world data complement clinical trial results by examining abemaciclib use among patients treated in routine clinical practice. The sizeable number of patients treated with prior CDK4 & 6i, chemotherapy, and/or visceral metastases at abemaciclib initiation suggest that many patients had very advanced disease and/or were in later stages of their treatment. These data confirm a higher percentage of patients treated with previous CDK4 & 6i than reported previously, reinforcing the importance of the ongoing, prospective clinical trials evaluating outcomes following progression on CDK4 & 6i.

Full population results from the core phase of CompLEEment-1, a phase 3b study of ribociclib plus letrozole as first-line therapy for advanced breast cancer in an expanded population

PURPOSE

CompLEEment-1 is a phase 3b trial in an expanded patient population with hormone receptor-positive (HR +), human epidermal growth factor receptor-2-negative (HER2-) advanced breast cancer (ABC), the largest current trial of cyclin-dependent kinase 4 and 6 inhibitors in ABC.

METHODS

Patients treated with ≤ 1 line of prior chemotherapy and no prior endocrine therapy for ABC received ribociclib 600 mg/day (3-weeks-on/1-week-off) plus letrozole 2.5 mg/day and additionally monthly goserelin/leuprolide in men and pre-/perimenopausal women. Eligibility criteria allowed inclusion of patients with stable CNS metastases and an Eastern Cooperative Oncology Group performance status of 2. Primary objectives were safety and tolerability, and secondary objectives were efficacy and quality of life (QoL).

RESULTS

Overall, 3,246 patients were evaluated (median follow-up 25.4 months). Rates of all-grade and grade ≥ 3 treatment-related adverse events (AEs) were 95.2% and 67.5%, respectively. Treatment-related discontinuations due to all grade and grade ≥ 3 AEs occurred in 12.9% and 7.3% of patients, respectively. Rates of all-grade AEs of special interest (AESI) were as follows: neutropenia (74.5%), increased alanine aminotransferase (16.2%), increased aspartate aminotransferase (14.1%), and QTcF prolongation (6.7%); corresponding values for grade ≥ 3 AESI were 57.2%, 7.7%, 5.7%, and 1.0%, respectively. Median time to progression was 27.1 months (95% confidence interval, 25.7 to not reached). Patient QoL was maintained during treatment.

CONCLUSION

Safety and efficacy data in this expanded population were consistent with the MONALEESA-2 and MONALEESA-7 trials and support the use of ribociclib plus letrozole in the first-line setting for patients with HR + , HER2- ABC.

TRIAL REGISTRATION

linicalTrials.gov NCT02941926.

Palbociclib and beyond for the treatment of HR + HER2- metastatic breast cancer: an Asian-Pacific perspective and practical management guide on the use of CDK4/6 inhibitors

Breast cancer is the most frequent cancer amongst women worldwide including in Asia where the incidence rate is rapidly increasing. Even with treatment, around 30% of patients with early breast cancer progress to metastatic disease, with hormone receptor positive (HR+) and human epidermal growth factor receptor 2 negative (HER2-) breast cancer the most common phenotype. First-line endocrine therapy targeting the estrogen receptor signaling pathway provides a median progression-free survival or time to progression of 6-15 months in HR + HER2- metastatic breast cancer. Recently, cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors, combined with endocrine therapy, have achieved more than two years median progression-free survival in HR + HER2- metastatic breast cancer. However, the characteristics of the Asian breast cancer population differ from those of Western populations and need to be considered when selecting a suitable treatment. Breast cancer is diagnosed at a younger age in Asian populations and late stage at presentation is generally more common in low-/middle-income countries than high-income countries. Consequently, the proportion of premenopausal women with metastatic breast cancer is higher in Asian compared with Western populations. While CDK4/6 inhibitors have been approved in the USA (FDA) since 2015, experience with them in Asia is more limited. We review the experience with the CDK4/6 inhibitor palbociclib in Asian patients with HR + HER2- metastatic breast cancer and provide guidance on the use of palbociclib in these patients.

Review of concepts in therapeutic decision-making in HER2-negative luminal metastatic breast cancer

Purpose

Hormone receptor (HR)-positive, Human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC) requires a therapeutic approach that takes into account multiple factors, with treatment being based on anti-estrogen hormone therapy (HT). As consensus documents are valuable tools that assist in the decision-making process for establishing clinical strategies and optimize the delivery of health services, this consensus document has been created with the aim of developing recommendations on cretiera for hormone sensitivity and resistance in HER2-negative luminal MBC and facilitating clinical decision-making.

Methods

This consensus document was generated using a modification of the RAND/UCLA methodology, which included the definition of the project and identification of issues of interest, a non-exhaustive systematic review of the literature, an analysis and synthesis of the scientific evidence, preparation of recommendations, and external evaluation with a panel of 64 medical oncologists specializing in breast cancer.

Results

A Spanish panel of experts reached consensus on 32 of the 32 recommendations/conclusions presented in the first round and were accepted with an approval rate of 100% about definition of metastatic disease not susceptible to local curative treatment, definition of hormone sensitivity and hormone resistance in metastatic luminal disease and therapeutic decision-making.

Conclusion

We have developed a consensus document with recommendations on the treatment of patients with HER2-negative luminal MBC that will help to improve therapeutic benefits.

Recent advances of cyclin-dependent kinases as potential therapeutic targets in HR+/HER2- metastatic breast cancer: a focus on ribociclib

In normal cell cycle progression, transition of G0/G1 phase to synthesis (S) phase for breast and other cells is regulated by association of cyclin D and cyclin-dependent kinases 4 and 6 (CDK4/6) that leads to phosphorylation of retinoblastoma (Rb) protein. Imbalance of this cyclin D-CDK4/6-inhibitors of CDK4/6-Rb phosphorylation pathway is associated with tumorigenesis of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancers. Despite effective first-line endocrine therapy, HR+/HER2- metastatic breast cancers remain still incurable. Currently, advances in understanding of cell cycle checkpoints are evolving as promising strategy to target in treatment of various types of cancers including breast cancer. Therapies that target this cell cycle machinery in HR+/HER2- breast cancers are getting approval by the US Food and Drug administration (FDA) including ribociclib (LEE011). Ribociclib got the first FDA approval in March 13, 2017, as an initial therapy for HR+/HER2- advanced or metastatic breast cancer in combination with an aromatase inhibitor. This review, therefore, addresses the role of selective CDK4/6 inhibitors in advanced or metastatic breast cancer with a specific focus on ribociclib. Some findings of clinical trials involving ribociclib found pivotal benefits of ribociclib in HR+/HER2- metastatic breast cancer in terms of prolonging progression-free survival and objective response rates. Daily dosage range of the drug for such benefits is 50-900 mg with common daily doses of 400 or 600 mg and 600 mg in early and advanced breast cancer therapies, respectively. Along with its therapeutic benefits, however, more incident but manageable dose-limiting grade 3 or 4 toxicities, primarily hematologic adverse events, are common in patients treated with ribociclib. Generally, there are several active clinical trials undergoing to investigate the clinical efficacy and toxicity profile of the drug in various cancerous conditions other than breast cancer and will likely benefit patients with other cancer types.