Clinical Research Directory

Observational Study of Gut Microbiota in Abemaciclib-Treated Patients With and Without Diarrhea

Why is this study being done? Many patients with a type of breast cancer (called HR-positive) take a medicine called Abemaciclib. While this medicine is effective, a very common side effect is diarrhea, which can be severe enough to disrupt treatment and reduce quality of life. The reason why some patients get diarrhea and others do not is not well understood. This study aims to investigate whether the natural bacteria living in the gut (known as the gut microbiome) play a role in this side effect. Researchers will compare the gut bacteria of patients who develop diarrhea with those who do not. What will happen in the study? This is an observational study, which means that patients will receive their normal cancer treatment and will not be given any new or experimental drugs as part of this initial phase. * Patients who are already being treated with Abemaciclib will be invited to join. * They will be placed into one of two groups: those who experience diarrhea and those who do not. * Participants will be asked to provide stool (feces) samples and may also provide optional blood samples at specific times during their treatment. * Researchers will analyze these samples in the lab to study the types and functions of the gut bacteria. Who can participate? * Adult women (aged 18-75) diagnosed with HR-positive breast cancer. * Currently receiving treatment with Abemaciclib for at least 2 weeks. * Must be willing to provide informed consent and follow the study procedures. What are the potential benefits? Participants will not receive any direct medical benefit from taking part in this study. However, the information learned may help researchers better understand why diarrhea occurs and, in the future, could lead to new ways to prevent or treat this side effect for other cancer patients. How is privacy protected? All personal information and samples collected will be de-identified using a unique code. This means that the data used for analysis cannot be directly linked back to the participant's identity. All data is stored securely according to strict ethical guidelines.

Pharmacokinetic Model of Abemaciclib: Correlation With Severe Diarrhea as the Primary Toxicity Endpoint in Patients With Localized Hormone Receptor-positive Breast Cancer

Remarkable progress has recently been made in the treatment of locally advanced, hormone receptor-positive, HER2-negative breast cancer with a high risk of recurrence, thanks to the addition of abemaciclib to endocrine therapy. This combination has led to a significant improvement in invasive disease-free survival. However, despite the combination's acceptable safety profile, 38% of patients experience grade 3 or higher diarrhea, and 23% experience grade 3 or higher neutropenia. This toxicity can lead to the premature discontinuation of treatment, limiting the benefits of this molecule. As with all oral therapies, the pharmacokinetics of abemaciclib lie at the intersection of efficacy and toxicity and can be modified by several external factors. The hypothesis of the study is that abemaciclib's toxicity is correlated with its plasma levels and that its concentration is modified by certain patient characteristics. To this end, a pharmacokinetic model of abemaciclib could be developed using a prospective, multicenter, real-world blood dosage study. This study will describe the relationship between abemaciclib concentration and diarrhea and severe neutropenia, as classified by CTCAE, as well as potential clinical and drug interactions. It is hoped that this model demonstrates the importance of monitoring abemaciclib concentrations. This could lead to a therapeutic trial in which the abemaciclib dose is adjusted according to concentration to limit toxicity while maintaining efficacy.

Evaluation of Adherence to Cell Cycle Inhibitors Used as Adjuvant Therapy in Patients With Localized Breast Cancer at High Risk of Recurrence.

Hormone receptor-positive (HR+) breast cancers represent the most common histological subtype of breast cancer, accounting for approximately 75% of cases, regardless of HER2 (human epidermal growth factor receptor 2) status (1). Adjuvant endocrine therapy (ET), including tamoxifen and aromatase inhibitors (AIs), is an effective pharmacological treatment for improving the prognosis of HR+ breast cancer, reducing the risk of recurrence by up to 50% (2-3-4-6). Despite its proven prognostic benefit, the full potential of endocrine therapy is not realized due to patient non-adherence (i.e., failure to comply with prescribed treatment). Adjuvant endocrine therapy is generally prescribed for a duration of 5 to 10 years. However, up to 40% of patients discontinue treatment prematurely, and 30% take the medication less frequently than prescribed. Poor adherence and low treatment persistence carry a substantial mortality burden: non-adherence is associated with a 49% increase in all-cause mortality. A retrospective analysis of a large database including more than 8,700 patients showed a 10-year survival rate of 80.7% among women who continued treatment, compared with 73.6% among those who discontinued adjuvant therapy prematurely (p \< 0.001). Among patients who continued treatment, the survival rate was 82% in those who were fully adherent, versus 78% in those who were only partially adherent (7-16). The literature has documented a wide range of risk factors associated with non-adherence to or discontinuation of long-term adjuvant endocrine therapy. Treatment-related adverse effects, including hot flashes, joint stiffness, and sexual dysfunction, are common and may lead to treatment discontinuation. Fear of side effects may also prevent some patients from initiating or maintaining endocrine therapy. Others may not be fully convinced of the necessity of adjuvant endocrine therapy, particularly in the absence of overt signs of cancer. In addition, supportive care required to manage side effects is often inadequately reimbursed, making low income-combined with broader socioeconomic factors-a potential barrier to optimal adherence. Some patients may also experience difficulties remembering to take their medication regularly. The relative importance and contribution of these factors to non-adherence may evolve over time. Other factors may also play a role, including sociodemographic characteristics (low income, living alone, or unemployment). Nevertheless, a residual risk of recurrence persists after five years of well-conducted standard endocrine therapy, extending up to two decades after diagnosis, particularly in patients with early-stage breast cancer stages II and III. In this higher-risk population, two phase III trials, monarchE and NATALEE, have recently evaluated the addition of a cell cycle inhibitor (CDK4/6 inhibitor) to standard adjuvant endocrine therapy and reported positive results with a reduction in the risk of relapse. In the NATALEE trial, quality of life was assessed in all patients in the ribociclib plus aromatase inhibitor group (n = 2,549) versus the aromatase inhibitor alone group (n = 2,552). Mean scores did not differ significantly from baseline for any of the analyzed domains. Similarly, no significant change from baseline was observed in either treatment group. However, it is important to note that 33.8% of patients discontinued ribociclib and 20% discontinued both endocrine therapy and ribociclib in the NATALEE trial, which is consistent with data from the literature. In the monarchE trial, 16.6% of patients discontinued abemaciclib, and 6% discontinued both abemaciclib and endocrine therapy, while only 0.8% discontinued endocrine therapy in the control group. These findings are not consistent with previously published data. To our knowledge, no real-world study has evaluated CDK4/6 inhibitors in combination with endocrine therapy in the adjuvant treatment of HR+/HER2-negative breast cancer. AdheRA is a prospective multicenter cohort study of patients with early-stage HR+/HER2-negative breast cancer at high risk of recurrence, eligible for a combination of endocrine therapy and a CDK4/6 inhibitor such as abemaciclib or ribociclib in the adjuvant setting, aiming to assess treatment adherence and the reasons for non-adherence.

Adjuvant Abemaciclib for Locoregional Recurrence of HR-positive, HER2-negative Breast Cancer (JCOG2313, AURA)

The JCOG2313 trial is a multicenter, randomized, phase III study designed to evaluate the efficacy and safety of adjuvant abemaciclib in combination with endocrine therapy versus endocrine therapy alone in patients with hormone receptor (HR)-positive, HER2-negative breast cancer who have undergone curative treatment for their first locoregional recurrence (LRR). Although HR-positive, HER2-negative breast cancer generally has a favorable prognosis, LRR-such as ipsilateral breast tumor recurrence (IBTR), chest wall recurrence, or regional lymph node recurrence-remains a clinically significant event that increases the risk of distant metastasis. While endocrine therapy is standard in this setting, the benefit of adding chemotherapy or other agents remains unclear, and treatment strategies vary widely. Abemaciclib, a CDK4/6 inhibitor, has shown survival benefit in the adjuvant setting for high-risk early breast cancer. However, its role in post-LRR adjuvant treatment has not been evaluated in a randomized setting. This study aims to determine whether the addition of abemaciclib to endocrine therapy can improve invasive disease-free survival (IDFS) in patients after LRR. Eligible patients are randomized 1:1 to receive either endocrine therapy alone or endocrine therapy plus abemaciclib (150 mg twice daily for 2 years). The primary endpoint is IDFS. Secondary endpoints include distant recurrence-free survival, breast cancer-specific survival, overall survival, and safety. A total of 290 patients will be enrolled. Randomization is stratified by site of recurrence, endocrine resistance, perioperative chemotherapy, and institution. Additionally, a prospective ancillary study will assess circulating tumor DNA (ctDNA) as a biomarker for molecular residual disease (MRD). Plasma samples will be collected at predefined time points to evaluate the prognostic and predictive value of ctDNA for relapse and treatment response. The JCOG2313 trial addresses an unmet need in the management of HR-positive, HER2-negative LRR and may contribute to the establishment of a new standard systemic therapy and personalized monitoring strategies.

Predicting clinicAL outcoMes During First-line CDK4/6 Inhibitors Plus Endocrine Therapy in Patients With Advanced Hormone REceptor-poSitive HER2-negative Breast Cancer: the Retrospective-prospective Multicenter Italian PALMARES-2 Study

PALMARES-2 is a retrospective/prospective, observational, multicenter, population-based study, aiming at providing real-world evidences on HR+/HER2- aBC patients treated with first-line CDK4/6i plus ET. The present study has the objective to collect data coming from different sources, i.e. RWD, medical images and biological samples, from patients treated with CDK4/6i as first-line of therapy for HR+/HER2- aBC. In consideration of the complexity of data collected and different objectives of the study, this master protocol foresees different sub-studies, which encompasses different methodologies for data collection, data extraction and analyses.

Retrospective Observational Study of the Safety and Toxicity Management of Abemaciclib in Combination with Adjuvant Hormone Therapy in Patients with RH+ ,HER2-nonoveramplified Breast Cancer, Real-life Data (MONARCHE29)

Overall survival at 8 years under treatment for localized hormone-dependent breast cancer is 93.3% (1). Adjuvant therapy, especially hormone therapy, helps reduce the risk of recurrence. However, the risk of relapse remains significant, estimated at around 20% according to studies. The SOFT study, which compares the type of hormone therapy used in premenopausal patients, estimates a relapse risk of 21.1% at 8 years (1), especially when there is initial lymph node involvement. In fact, in cases of lymph node involvement, the cumulative relapse rate at 10 years after stopping hormone therapy ranges between 19% and 36% (2), and the risk of death from breast cancer 20 years after stopping hormone therapy is estimated at 28% to 49% (2). CDK4/6 inhibitors first demonstrated their efficacy at the metastatic stage. Abemaciclib improved median survival to 46.7 months compared to a median of 37.3 months with hormone therapy alone (Monarch 2 (3) and Monarch 3 (4)). Palbociclib showed in PALOMA-2 (5) an improvement in progression-free survival (24.8 months versus 14.5 months) without an improvement in overall survival. Ribociclib, in turn, demonstrated in MONALEESA 2 (6) an improvement in PFS (25.3 months versus 16 months) and in overall survival (63.9 months versus 51.4 months). These treatments have become the standard first-line treatment for patients with RH+ HER2 non-amplified breast cancer. Given the results in advanced lines, CDK4/6 inhibitors have been the subject of studies in localized breast cancer, particularly in this high-risk population where the recurrence rate remains significant. The MONARCH-E study, published on September 20, 2020 (7), led to the approval of Abemaciclib by European authorities at the time of the initial publication (median follow-up of 15.4 months) and to reimbursement starting in May 2023 after a second interim analysis (8) in this at-risk population, with a 5.6% reduction in relapse risk after 42 months of follow-up compared to hormone therapy alone. It is crucial to clearly define the at-risk population in order to offer them treatment intensification while maintaining a satisfactory quality of life. The group benefiting from Abemaciclib presented grade III toxicity in 43% of cases and grade IV toxicity in 2.5%. Real-world data are needed to better understand the management and toxicity of this treatment.