Real-World Outcomes of Ribociclib and Aromatase Inhibitor Use in First Line Hormone Receptor Positive, HER2-Negative Metastatic Breast Cancer

Real-World Evidence of Ribociclib Plus Aromatase Inhibitors as First-Line Treatment in Advanced Breast Cancer: The BrasiLEEira Study

PURPOSE

Cyclin inhibitors plus endocrine therapy represent the reference standard for hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) locally advanced or metastatic breast cancer (ABC). Efficacy results on hard end points such as overall survival come from well-designed randomized clinical trials (RCTs). However, a limitation of RCTs is the low external results validity, and their extrapolation to a broader population may not be appropriate. Real-world studies can overcome these limitations, also increasing the reliability of RCTs.

MATERIALS AND METHODS

The BrasiLEEira was an observational, longitudinal, retrospective, multicenter study to evaluate the effectiveness and safety of ribociclib plus nonsteroidal aromatase inhibitors in Brazilian women age 18 years or older with HR+/HER2- ABC. The study was approved by the institutional review boards of all 11 hospitals. Data were collected anonymously from medical records using an electronic case report form designed by an independent academic research organization, which conducted the study considering all recommendations of international guidelines. The primary end point was 1-year progression-free survival (PFS) rate. Secondary end points included mortality, dose reduction, and safety.

RESULTS

The mean age of 76 patients was 57 years, and 28.9% were Black/Brown. The most prevalent comorbidity was arterial hypertension (34.7%). About 26.0% had endocrine-resistant disease, and 54.1% had more than three metastatic sites. The PFS rate was 77.6%. Three patients died (3.9%). Dose reductions occurred in 37.7% of patients. The most common adverse event was neutropenia (68.4%).

CONCLUSION

The high-quality evidence from the BrasiLEEira study corroborates the RCTs' findings, expanding its validity to a broader spectrum and underrepresented population who may benefit from ribociclib treatment.

Cardiovascular complications of ribociclib in breast cancer patients

Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors have unprecedentedly advanced hormone-dependent breast cancer treatment paradigm. In the metastatic setting, ribociclib has consistently demonstrated survival benefit in pre-, peri-, and postmenopausal patients, conjugating efficacy with health-related quality of life preservation. Accordingly, the emergence of cardiac and/or vascular adverse events related to this novel targeted agent is gaining significant interest. This narrative review provides an overview of the incidence and spectrum of cardiovascular toxicity, in both clinical trial framework and real-world evidence. The potential pathogenetic mechanism, along with the available diagnostic parameters including biomarkers, and proper management, are also summarized.

Exploring adherence in patients with advanced breast cancer: focus on CDK4/6 inhibitors

Treatment adherence is crucial for optimal outcomes in advanced breast cancer, but can be challenging due to various factors, i.e. patients' attitudes and behavior upon diagnosis, and complex therapies with high adverse effect rates. Our aim was to explore the adherence to oral anticancer medications (OAM) in women with advanced breast cancer, focusing on cyclin-dependent kinase 4 and 6 inhibitors (CDKI), and identify factors associated with the adherence. We conducted a cross-sectional study at the University Hospital Centre Zagreb, Croatia, involving women with stage IV advanced breast cancer receiving OAM. Data collection included a questionnaire assessing socio-demographic and clinical information, Beck Depression Inventory-II for depressive symptoms, Medication Adherence Report Scale (MARS-5) for adherence to OAM, and Beliefs about Medicines Questionnaire. Plasma concentrations of CDKI were confirmed by LC-MS/MS in three randomly selected participants. A total of 89 women were included. The most prescribed OAMs were anti-estrogen (71.3 %) and CDKI (60.9 %). MARS-5 scores (mean: 24.1 ± 1.6) correlated with CDKI plasma concentrations. Forgetfulness was the primary reason for non-adherence (25.9 %). Women receiving CDKI (p = 0.018), without depressive symptomatology (p = 0.043), and with more positive beliefs about medicines were more adherent (p < 0.05). This study enhances understanding of medication adherence in advanced breast cancer and identifies influential factors.

HR+/HER2- de novo metastatic breast cancer: a true peculiar entity?

De novo metastatic breast cancer (dnMBC) accounts for ~6-10% of all breast cancers and for ~30% of MBC with increasing incidence over time. Hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR⁺/HER2^-) tumours are the most frequent subtype with a similar incidence to that observed amongst recurrent MBC (rMBC). Higher frequency of PI3KCA and ARID2 mutations and a lower frequency of ESR1 mutations and of genes involved in DNA damage, as compared with rMBC, have been reported in HR⁺/HER2^- dnMBC; however, these are not correlating with prognosis, whilst tumour mutational burden is inversely correlated with outcome. Bone represents the most frequent metastatic site, being the single site in up to 60% of patients with dnMBC. HR⁺/HER2^- dnMBC has been generally reported to have better outcomes than rMBC, with a median overall survival ranging from 26 months to nearly 5 years in patients with favourable features such as age <40 years and bone-only disease, but not when compared with patients with late recurring disease (≥2-5 years). Analyses of the de novo cohorts within randomized clinical trials and large real-world series report a better outcome after treatment with CDK4/6 inhibitors and endocrine agents as compared to rMBC. Despite the limitations of retrospective studies and controversial results of the randomized trials, locoregional treatment of the primary tumour after response to systemic therapy appears to confer a survival benefit, particularly in patients with favourable prognostic factors. Altogether genomic, biological and clinical findings highlight HR⁺/HER2^- dnMBC as a peculiar entity as compared with rMBC and deserve a dedicated treatment algorithm. This article is part of the Tackling clinical complexity in breast cancer Special Issue: https://www.drugsincontext.com/special_issues/tackling-clinical-complexity-in-breast-cancer/.