Treatment satisfaction in women receiving palbociclib combination therapies for advanced/metastatic breast cancer

First-line therapy with palbociclib in patients with advanced HR+/HER2- breast cancer: The real-life study PALBOSPAIN

PURPOSE

To evaluate the efficacy and safety of first-line therapy with palbociclib in a Spanish cohort treated after palbociclib approval.

METHODS

PALBOSPAIN is an observational, retrospective, multicenter study evaluating real-world patterns and outcomes with 1 L palbociclib in men and women (any menopausal status) with advanced HR+/HER2- BC diagnosed between November 2017 and November 2019. The primary endpoint was real-world progression-free survival (rw-PFS). Secondary endpoints included overall survival (OS), the real-world response rate (rw-RR), the clinical benefit rate, palbociclib dose reduction, and safety.

RESULTS

A total of 762 patients were included. The median rw-PFS and OS were 24 months (95% CI 21-27) and 42 months (40-not estimable [NE]) in the whole population, respectively. By cohort, the median rw-PFS and OS were as follows: 28 (95% CI 23-39) and 44 (95% CI 38-NE) months in patients with de novo metastatic disease, 13 (95% CI 11-17) and 36 months (95% CI 31-41) in patients who experienced relapse < 12 months after the end of ET, and 31 months (95% CI 26-37) and not reached (NR) in patients who experienced relapse > 12 months after the end of ET. rw-PFS and OS were longer in patients with oligometastasis and only one metastatic site and those with non-visceral disease. The most frequent hematologic toxicity was neutropenia (72%; grade ≥ 3: 52.5%), and the most common non-hematologic adverse event was asthenia (38%).

CONCLUSION

These findings, consistent with those from clinical trials, support use of palbociclib plus ET as 1 L for advanced BC in the real-world setting, including pre-menopausal women and men.

TRIAL REGISTRATION NUMBER

NCT04874025 (PALBOSPAIN). Date of registration: 04/30/2021 retrospectively registered.

Digging in real-word electronic database for assessing CDK 4/6 inhibitors adherence in breast cancer patients from Romania

Introduction: It is imperative for patients to respect the prescribed treatments to achieve the anticipated clinical outcomes, including the outpatients receiving oral anti-cancer drugs such as selective cyclin-dependent kinase 4/6 inhibitors (CDK 4/6i). With the introduction of three CDK 4/6i drugs in the Romanian pharmaceutical market in 2018, our study aimed to evaluate medication adherence and the influencing factors among patients undergoing treatment with palbociclib, ribociclib, or abemaciclib for advanced or metastatic breast cancer. Methods: Medication adherence was assessed using the Proportion of Days Covered (PDC) method, and Spearman correlation analysis was conducted to explore the relationships between adherence, age, gender, and follow-up duration. Results: The study enrolled 330 breast cancer patients, with an average follow-up period of 14.6 ± 12.5 months for palbociclib, 10.6 ± 7.1 months for ribociclib, and 8.6 ± 6.4 months for abemaciclib-treated patients. A small proportion of patients demonstrated non-adherence: 12.8% for palbociclib, 14.6% for ribociclib, and 14.7% for abemaciclib. Among patients receiving palbociclib, there was no significant correlation between adherence, age (rho = 0.07, p = 0.35), or gender (rho = -0.144, p = 0.054). However, a significant correlation was found with the duration of follow-up (rho = -0.304, p < 0.0001). Similar results were observed for patients receiving ribociclib or abemaciclib. Most patients received combination therapy with letrozole (46%) and exemestane (13%) for palbociclib, letrozole (48%) and fulvestrant (19%) for ribociclib, and fulvestrant (39%) and letrozole (27%) for abemaciclib, Discussion: High adherence rates were observed among patients treated with CDK 4/6i drugs, with no significant differences noted among the three drugs in this class. However, the collected patient data was limited, lacking information on adverse reactions that could potentially lead to treatment discontinuation, as determined by the oncologist's decision not to prescribe. Consequently, a comprehensive understanding of all factors contributing to the low adherence levels is hindered.

Development and validation of a rapid psychosocial well-being screening tool in patients with metastatic breast cancer

Objective

Methods

Results

Conclusion

Adjuvant Palbociclib for Early Breast Cancer: The PALLAS Trial Results (ABCSG-42/AFT-05/BIG-14-03)

PURPOSE

Palbociclib is a cyclin-dependent kinase 4 and 6 inhibitor approved for advanced breast cancer. In the adjuvant setting, the potential value of adding palbociclib to endocrine therapy for hormone receptor-positive breast cancer has not been confirmed.

PATIENTS AND METHODS

In the prospective, randomized, phase III PALLAS trial, patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative early breast cancer were randomly assigned to receive 2 years of palbociclib (125 mg orally once daily, days 1-21 of a 28-day cycle) with adjuvant endocrine therapy or adjuvant endocrine therapy alone (for at least 5 years). The primary end point of the study was invasive disease-free survival (iDFS); secondary end points were invasive breast cancer-free survival, distant recurrence-free survival, locoregional cancer-free survival, and overall survival.

RESULTS

Among 5,796 patients enrolled at 406 centers in 21 countries worldwide over 3 years, 5,761 were included in the intention-to-treat population. At the final protocol-defined analysis, at a median follow-up of 31 months, iDFS events occurred in 253 of 2,884 (8.8%) patients who received palbociclib plus endocrine therapy and in 263 of 2,877 (9.1%) patients who received endocrine therapy alone, with similar results between the two treatment groups (iDFS at 4 years: 84.2% v 84.5%; hazard ratio, 0.96; CI, 0.81 to 1.14; P = .65). No significant differences were observed for secondary time-to-event end points, and subgroup analyses did not show any differences by subgroup. There were no new safety signals for palbociclib in this trial.

CONCLUSION

At this final analysis of the PALLAS trial, the addition of adjuvant palbociclib to standard endocrine therapy did not improve outcomes over endocrine therapy alone in patients with early hormone receptor-positive breast cancer.

Quality of life of therapies for hormone receptor positive advanced/metastatic breast cancer: Regulatory aspects and clinical impact in Europe

In recent years, the number of trials incorporating health-related quality of life (HRQoL) data has increased. The impact of HRQoL on regulatory decision making in the European context and on clinical practice is not well established. We conducted an analysis of the role of QoL data extracted from the clinical trials of the drugs approved for hormone receptor positive/HER2-negative advanced/metastatic breast cancer (mBC). The results from the HRQoL were collected and a meta-analysis was performed to evaluate the impact of experimental drugs compared to standard treatments. The results showed a non-detrimental effect in HRQoL from the new treatments. As regards the approval process, from an examination of the European Medicine Agency (EMA) documents, HRQoL was reported nonextensively and contained and discussed in the European assessment reports (EPARs) for eleven trials in the approval process and cited in three cases in the EPARs and summary of medicinal product characteristics (SmPC). An effort should be made by all the stakeholders to increase the visibility of the HRQoL results in order to allow increased consideration in the approval process to make QoL data more easily and visibly available for the clinician and the patients. The evaluation should be reflected in the SmPC in order to increase the amount of information provided to the physician.

Real-world clinical outcome and toxicity data and economic aspects in patients with advanced breast cancer treated with cyclin-dependent kinase 4/6 (CDK4/6) inhibitors combined with endocrine therapy: the experience of the Hellenic Cooperative Oncology Group

Background

We evaluated real-world clinical outcomes and toxicity data and assessed treatment-related costs in patients with advanced breast cancer who received treatment with cyclin-dependent kinase inhibitors (CDKi).

Patients and methods

We conducted a prospective–retrospective analysis of patients with advanced hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer who received a CDKi, in combination with endocrine therapy, at any line of treatment. The primary endpoint was progression-free survival (PFS). Cost analysis was conducted from a public third-payer (National Organization for Healthcare Services Provision (EOPYY)) perspective, assessing only costs related to direct medical care, including drug therapy costs and adverse drug reaction (ADR)-related costs.

Results

From July 2015 to October 2019, 365 women received endocrine therapy combined with CDKi; median age was 61 years, postmenopausal 290 (80.6%) patients. CDKi were administered as first-line treatment in 149 (40.9%) patients, second-line treatment in 96 (26.4%) and third-line treatment and beyond in 119 (32.7%) patients. The most common adverse events were neutropenia, anaemia, thrombocytopenia and fatigue. Grade 3–4 adverse events occurred in 86 (23.6%) patients, whereas 8 (2.2%) patients permanently discontinued treatment due to toxicity. The median PFS for patients who received CDKi as first-line, second-line and third-line treatment and beyond was 18.7, 12 and 7.4 months, respectively. The median overall survival since the initiation of CDKi treatment was 29.9 months (95% CI: 23.0–not yet reached (NR)). The mean pharmaceutical therapy cost estimated per cycle was 2 724.12 € for each patient, whereas the main driver of the ADR-related costs was haematological adverse events.

Conclusions

Treatment with CDKi was well tolerated, with a low drug discontinuation rate. Patients who received CDKi as first-line treatment had improved PFS and OS compared with second-line treatment and beyond. The main component of direct medical costs assessed in the cost analysis comprises CDKi pharmaceutical therapy costs.

Trial registration number

NCT04133207

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.

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.

Cyclin-dependent kinase 4/6 inhibitors for cancer therapy: a patent review (2015 - 2019)

INTRODUCTION

Cyclin-dependent kinases 4 and 6 (CDK4/6) along with their upstream/downstream components are pivotal regulators for the cell cycle progression. The dysfunction of CDK4/6 is the common feature and promoting factor in various cancer types. In-depth research on CDK4/6 inhibitors has afforded therapeutic agents, while new challenges and ideas are emerging concomitantly.

AREAS COVERED

This review focuses on patent publications related to CDK4/6 inhibitors which could be utilized for anti-cancer purposes during the period 2015-2019.

EXPERT OPINION

The increasingly comprehensive and thorough understanding of CDK4/6 inhibitors facilitates them to break through the current limitations. Hence the utilization of CDK4/6 inhibitors for cancer therapy in the near future is likely to be performed in diverse forms and for distinct purposes. Selectivity over kinases is still crucial to new agent development but shall be prudently dealt with. The gradually revealing of resistance and adverse events proposed another issue that calls for new tackling strategies.

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

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

High-Mobility Group Box 1 (HMGB1) Promotes Angiogenesis and Tumor Migration by Regulating Hypoxia-Inducible Factor 1 (HIF-1α) Expression via the Phosphatidylinositol 3-Kinase (PI3K)/AKT Signaling Pathway in Breast Cancer Cells

Background

High-mobility group box 1 (HMGB1) is an essential contributor towards initiation and progression of many kinds of cancers. Nevertheless, our understanding of the molecular etiology of HMGB1-modulated vasculogenesis, as well as invasion, of breast cancer is poor. This study explored HMGB1 expression in breast cancer and its role in the development and spread of malignancy.

Material/Methods

We enrolled 15 patients with breast cancer who received primary surgery at the Department of Thyroid and Breast Surgery in our hospital. HMGB1 was recorded and analyzed.

Results

Our investigation successfully proves that HMGB1 is upregulated in breast cancer tissues in comparison to the surrounding non-malignant tissues. HMGB1 enhanced vessel formation in breast cancer tissues by regulating hypoxia-inducible factor 1 (HIF-1α), which in turn upregulates the expression of VEGF. Furthermore, HMGB1-mediated upregulation of HIF-1α relies on its ability to stimulate the phosphatidylinositol 3-kinase (PI3K) pathway to reinforce AKT subunit phosphorylation. HMGB1 overexpression reinforces the vasculogenesis in malignancies not only in vivo but also in vitro. Additionally, shRNA knockdown of HMGB1 prohibited the vessel-forming and invasive capabilities, downregulated VEGF and HIF-1α, and suppressed AKT phosphorylation in breast cancer cells. Most importantly, PI3K/AKT axis suppression eliminated the effect of HMGB1-modulated vascularization and invasion in breast cancer cells.

Conclusions

Our research indicates that HMGB1 serves as a crucial regulator of malignant cell-modulated vessel formation and is involved in the development of malignancy. Our findings indicate that HMGB1 is a promising target for breast cancer treatment.