Search Results (53)

Background and Clinical Significance: Up to 30% of patients with HR+/HER2-early breast cancer (eBC) may experience distant recurrence, and patients with high-risk clinical features have a higher likelihood of recurrence. For these patients, the addition of a CDK4/6 inhibitor to standard adjuvant endocrine therapy (ET) has demonstrated a significant reduction in the risk of invasive and distant recurrence. Despite that, a small subset of patients still experience distant relapse. To date, the characteristics of patients who relapse on adjuvant CDK 4/6i are not well defined. Case Presentation: Here we report the case of a patient with early-stage HR+/HER2− breast cancer at high risk of recurrence, who experienced distant metastatic relapse during adjuvant therapy with abemaciclib plus ET, with a shift in the tumor subtype to triple-negative. Genomic alterations associated with ET and cyclin-dependent kinase 4 and 6 inhibitor resistance were analyzed with next-generation sequencing (NGS) carried out at recurrence. Results showed P53 and PI3KCA pathway alterations, but no ESR1 mutation or RB1 mutations. The duration was 12 months for adjuvant abemaciclib, and the first-line metastatic treatment lasted less than 3 months. Conversely, T-DXd administered due to the presence of HER2-low showed excellent effectiveness. Conclusions: The management of breast cancer relapse occurring during adjuvant therapy with CDK4/6 inhibitors is challenging. Performing a re-biopsy is crucial due to the possible loss of estrogen receptors, which would require a change in therapeutic strategy no longer based on endocrine therapy. In cases that remain luminal, knowledge of the mutational profile may help to offer patients novel targeted treatments. Full article

More than 70% of breast cancers are estrogen receptor-positive (ER⁺). Endocrine therapy that blocks estrogen signaling remains the cornerstone of treatment, yet relapses continue to affect many patients. Cyclin-dependent kinases 4 and 6 (CDK4/6) regulate the G1-S phase transition in the cell cycle, and pharmacological inhibition of this pathway has been successfully leveraged to reduce recurrence. CDK4/6 inhibitors combined with endocrine therapy are now the standard of care, although determining the optimal patient population for treatment remains a key challenge. A newly published study provides important insight, showing that loss of the NF1/neurofibromin tumor suppressor confers greater sensitivity to CDK4/6 inhibition, as these tumors rely heavily on CDK4/6 activity for survival under endocrine therapy. Full article

Malignant Peripheral Nerve Sheath Tumors (MPNSTs) are a deadly subtype of soft tissue sarcoma for which effective therapeutic options are lacking. Currently, the best treatment for MPNSTs is complete surgical resection with wide negative margins, but this is often complicated by the tumor size and location and/or the presence of metastases. Radiation or chemotherapy may be combined with surgery, but patient responses are poor. Targeted treatments, including small-molecule inhibitors of oncogenic proteins such as mitogen-activated protein kinase kinase (MEK), cyclin-dependent kinases 4 and 6 (CDK4/6), and Src-homology 2 domain-containing phosphatase 2 (SHP2), are promising therapeutics for MPNSTs, especially when combined together, but they have yet to gain approval. Immunotherapeutic approaches have been revolutionary for the treatment of some other cancers, but their utility as single agents in sarcoma is limited and not approved for MPNSTs. The immunosuppressive niche of MPNSTs is thought to confer inherent treatment resistance, particularly to immunotherapies. Remodeling an inherently “cold” tumor microenvironment into a “hot” immune milieu to bolster the anti-tumor activity of immunotherapies is of great interest throughout the cancer community. This review focuses on novel therapeutics that target dysregulated factors and pathways in MPNSTs, as well as different types of immunotherapies currently under investigation for this disease. We also consider how certain therapeutics may be combined to remodel the MPNST immune microenvironment and thereby generate a durable anti-tumor immune response to immunotherapy. Full article

Background: Cyclin-dependent kinases 4 and 6 (CDK4/6) are pivotal regulators of the cell cycle, whose dysregulation is closely linked to cancer progression. While synthetic CDK4/6 inhibitors such as Palbociclib and Ribociclib are clinically effective, their use is limited by significant adverse effects. Methods: In this study, the aqueous root extract of Thottea siliquosa, a traditionally used medicinal plant, was evaluated for its potential as a natural CDK4/6 inhibitor. Phytochemical profiling using GC-MS identified bioactive compounds, which were subsequently subjected to molecular docking, ADME prediction, and in vitro cell-based assays using HCT116 and L929 cells. Results: The docking results revealed that Isocorydine (−7.4 kcal/mol for CDK4 and −7.2 kcal/mol for CDK6) and Thunbergol (−6.5 kcal/mol for CDK4 and −7.0 kcal/mol for CDK6) exhibited promising binding affinities comparable to standard CDK inhibitors, Palbociclib (−7.2, −8.3 kcal/mol) and Ribociclib (−7.1, −8.1 kcal/mol). Among the other tested natural compounds, Squalene (−7.1 kcal/mol for CDK4) and 2-palmitoylglycerol (−5.2 kcal/mol for CDK4, −4.9 kcal/mol for CDK6) demonstrated moderate binding affinities. ADME analysis confirmed favorable drug-like properties with minimal toxicity alerts. The extract displayed dose-dependent cytotoxicity with an IC₅₀ of 140 μg/mL and reduced cell migration in HCT116 cells, indicating potential anti-proliferative effects. These findings suggest that T. siliquosa root extract, through synergistic phytochemical interactions, holds promise as a multi-targeted, plant-based therapeutic candidate for CDK4/6-associated cancers, warranting further in vitro and in vivo validation. Full article

Background/Objectives: Sacituzumab govitecan (SG) is an antibody–drug conjugate targeting Trop-2, approved for use in metastatic triple-negative breast cancer (mTNBC) and more recently in the hormone receptor-positive/HER2-negative (mHRPBC) subtype. While clinical trials have demonstrated its efficacy, real-world data—especially those involving both molecular subtypes—remain scarce. This multicenter, retrospective study aimed to evaluate real-world observational data describing the clinical outcomes, safety, and prognostic factors associated with SG treatment in patients with mTNBC or mHRPBC. Methods: A total of 68 patients treated with SG between 2022 and 2025 were included from multiple oncology centers in Turkey. Patients with mTNBC were required to have received at least one prior chemotherapy line, while mHRPBC patients had received at least two prior chemotherapy lines in addition to cyclin-dependent kinase 4 and 6 inhibitors (CDK 4/6) plus hormone therapy. The clinical outcomes—including the progression-free survival (PFS), overall survival (OS), and objective response rate (ORR)—were evaluated. Univariate and multivariate analyses were performed to identify factors influencing outcomes. Adverse events (AEs) were also documented and graded according to National Cancer Institute Common Terminology Criteria for Adverse Events version 5 (NCI-CTCAE v5.0). Results: The cohort included 35 (51.5%) mTNBC and 33 (48.5%) mHRPBC patients. The median PFS was 6.1 months, and the median OS was 12.5 months, with no significant differences between subtypes. The ORR was 52.9%, with a complete response observed in 10.3% of patients. A high Eastern Cooperative Oncology Group Performance Status (ECOG PS) and liver metastasis were independent predictors of poorer PFS and OS. Prior immunotherapy did not negatively impact SG’s efficacy. SG was generally well tolerated; the most common AEs were alopecia, anemia, neutropenia, and diarrhea. Treatment discontinuation due to AEs was rare (2.9%). Conclusions: SG was associated with similar clinical outcomes and tolerability in both the mTNBC and mHRPBC subtypes. Although the real-world PFS and OS outcomes mirror those seen in clinical trials, the absence of a control group means that these findings should be interpreted descriptively rather than as confirmation of treatment efficacy. Importantly, this study provides one of the first real-world datasets evaluating SG in the mHRPBC subgroup, highlighting its potential role beyond clinical trials. These results support SG as a valuable therapeutic option in heavily pretreated patients, warranting further prospective and biomarker-driven studies. Full article

Cyclin-dependent kinases (CDKs) are pivotal in regulating cell cycle progression and transcription, making them crucial targets in cancer research. The two types of CDKs that regulate different biological activities are transcription-associated CDKs (e.g., CDK7, 8, 9, 12, and 13) and cell cycle-associated CDKs (e.g., CDK1, 2, 4, and 6). One characteristic of cancer is the dysregulation of CDK activity, which results in unchecked cell division and tumor expansion. Targeting transcriptional CDKs, which control RNA polymerase II activity and gene expression essential for cancer cell survival, has shown promise as a therapeutic approach in recent research. While research into selective inhibitors for transcriptional CDKs is ongoing, inhibitors that target CDK4/6, such as palbociclib and ribociclib, have demonstrated encouraging outcomes in treating breast cancer. CDK7, CDK8, and CDK9 are desirable targets for therapy since they have shown oncogenic roles in a variety of cancer types, such as colorectal, ovarian, and breast malignancies. Even with significant advancements, creating selective inhibitors with negligible off-target effects is still difficult. This review highlights the need for more research to optimize therapeutic strategies and improve patient outcomes by giving a thorough overview of the non-transcriptional roles of CDKs in cancer biology, their therapeutic potential, and the difficulties in targeting these kinases for cancer treatment. Full article

Approximately 70–80% of breast cancers are estrogen receptor-positive (ER+), with 65% of these cases also being progesterone receptor-positive (ER+PR+). In most cases of ER+ advanced breast cancer, endocrine therapy (ET) serves as the first-line treatment, utilizing various drugs that inhibit ER signaling. These include tamoxifen, a selective estrogen receptor modulator (SERM); fulvestrant, a selective estrogen receptor degrader (SERD); and aromatase inhibitors (AIs), which block estrogen synthesis. However, intrinsic or acquired hormone resistance eventually develops, leading to disease progression. The combination of ET with cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6is) has been shown to significantly increase progression-free survival (PFS) and, in some cases, overall survival (OS). CDK4/6is works by arresting the cell cycle in the G1 phase, preventing DNA synthesis, and enhancing the efficacy of ET. This review highlights the key mechanisms of resistance to ET, whether used alone or in combination with biological agents, as well as emerging therapeutic strategies aimed at overcoming resistance. Addressing ET resistance remains a work in progress, and in the near future, better patient selection for different therapeutic approaches is expected through the identification of more precise biological and genetic markers. In particular, liquid biopsy may provide a real-time portrait of the disease, offering insights into mechanisms driving ET resistance and cancer progression. Full article

Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors have transformed the treatment landscape for patients with hormone receptor-positive (HR+)/HER2-negative (HER2−) breast cancer. However, their efficacy is influenced by various clinical and biological factors, including patient age, tumor biology, and treatment-related toxicities. The aim of this study is to evaluate the impact of demographic, clinical, and tumor-related characteristics on the efficacy of CDK4/6 inhibitors in a cohort of patients with metastatic HR+/HER2− breast cancer. We conducted a retrospective cohort study analyzing the outcomes of 95 patients with metastatic ER-positive, HER2-negative breast cancer (BC) treated with CDK4/6 inhibitors (ribociclib, palbociclib, and abemaciclib) in combination with endocrine therapy. The patient demographics, tumor characteristics, and treatment regimens were examined, with a primary focus on progression-free survival (PFS), overall survival (OS), time on treatment (TOT), and the influence of clinical and biological factors. Younger patients (under 50 years) demonstrated higher tumor aggressiveness, reflected by higher Ki67 levels and histological grades, which negatively impacted their survival outcomes. Ribociclib was associated with the highest survival benefit, particularly in younger patients. Older patients (over 50 years) showed greater rates of comorbidities and toxicity, with dose reductions correlated with improved survival outcomes. This study highlights the significance of personalized treatment strategies based on patient age, comorbidities, and tumor biology. Ribociclib shows superior efficacy in younger, less comorbid patients, while palbociclib remains a viable option for older patients with higher comorbidity burdens. Full article

Breast cancer is the most frequently diagnosed neoplasm in the world. It can be classified into four main subtypes, each of them showing differences in the expression of hormone receptor (HR), human epidermal growth factor receptor 2 (HER2), and in cell metabolism. Since 2015, when The U.S. Food and Drug Administration (FDA) approved the first cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor that regulates the cell cycle, treatment of HR+/HER2− BC has become much more effective. Currently, palbociclib, ribociclib, and abemaciclib are more often used both in combination with endocrine therapy as well as in monotherapy. Their application has been extensively verified in many clinical trials such as PALOMA-1,2,3, MONALEESA-1,2,3,7, and MONARCH-1,2,3, which allowed the verification of differences in their effectiveness, dosage, and adverse effects. Subsequent studies, MonarchE and NATALEE, examined the role of these inhibitors as adjuvant therapy, as well as at verifying their safety. Moreover, dalpiciclib is being investigated in HR+/HER2− BC treatment. This article will summarize clinical efficacy, recommendations, and differences in toxicity profile between palbociclib, ribociclib, and abemaciclib and will also discuss the possibility of using dalpiciclib in the treatment of breast cancer. Full article

Guidelines for the first-line treatment of Hormone Receptor-positive, HER2-negative advanced or recurrent breast cancer have shifted to combination therapies of a CDK4/6 inhibitor and endocrine therapy. However, determining an optimal subsequent therapy following CDK4/6 inhibitor progression remains challenging, especially for tumors lacking actionable mutations. Real-world data suggest that fulvestrant monotherapy is frequently selected in this post-CDK4/6 inhibitor setting. This review examines its therapeutic potential in this evolving landscape. A systematic literature search using PubMed and ClinicalTrials.gov identified 153 clinical trials published between 2017 and November 2024, from which ten studies met our strict inclusion criteria, focusing solely on fulvestrant monotherapy. These trials encompassed 1038 patients who had prior exposure to CDK4/6 inhibitors. The selected studies were categorized into three groups: monotherapy trials (EMERALD, SERENA-2, AMEERA-3, and ELAINE-1), combination therapy trials (CAPItello-291 and VERONICA), and CDK4/6 inhibitor rechallenge trials (post-MONARCH, PACE, PALMIRA, and MAINTAIN). The median progression-free survival for fulvestrant monotherapy was 3.18 months (range 1.9–5.3 months). Factors affecting the efficacy of fulvestrant monotherapy in second-line therapy include prior treatments, treatment duration, and genetic mutations. Given that the efficacy of fulvestrant was short-lived in the second or subsequent lines, participating in clinical trials is a vital option until a novel alternative treatment choice becomes available. Full article

Background and Objectives: Breast cancer is the most common malignant neoplasm worldwide and the most prevalent one among women. It represents the leading cause of cancer-related death among females. Cyclin-dependent kinase 4 and 6 inhibitors disrupt the cell cycle, inducing cellular senescence and, ultimately, apoptosis. Consequently, they have become a novel type of adjuvant therapy for the treatment of advanced or metastatic breast cancer characterised by positive hormone receptors and human epidermal growth factor receptor 2 (HER-2) negative. Methods: A systematic review was conducted, analysing the available literature on cyclin-dependent kinase 4 and 6 inhibitors published over the last five years. The aim was to evaluate the efficacy and safety of adding these drugs to the standard endocrine therapy for this pathology. Results: The combination of cyclin-dependent kinase 4 and 6 inhibitors with endocrine therapy was shown to improve progression-free survival, overall survival, and chemotherapy-free intervals in patients who received this combination therapy. Conclusions: The addition of CDK4/6 inhibitors to endocrine therapy in the treatment of advanced or metastatic breast cancer with positive hormone receptors and HER-2 negative significantly improved PFS, median survival, and chemotherapy-free intervals compared with the use of hormonal treatments alone or in combination with a placebo. Currently, CDK4/6 inhibitors are becoming established as a new standard treatment for this pathology, offering lower toxicity than chemotherapy. However, it is necessary to deeply investigate the mechanisms of treatment resistance and develop effective therapies to overcome them. Full article

Background and Objectives: Early-onset breast cancer (EOBC), particularly in patients under 40, presents with distinct biological characteristics and worse survival outcomes compared to late-onset cases. Despite intensive treatments, EOBC patients, especially those with hormone receptor-positive, HER2-negative (HR+/HER2-) subtypes, show poorer prognosis. CDK4/6 inhibitors, combined with endocrine therapy (ET) have become the standard for HR+/HER2- metastatic breast cancer, yet younger patients are underrepresented in clinical trials. This study aims to evaluate the efficacy of ribociclib and palbociclib with ET in HR+/HER2- metastatic breast cancer, addressing the critical gap in understanding treatment outcomes in younger patient populations. Materials and Methods: This multicenter, retrospective study evaluated the efficacy and safety of cyclin-dependent kinase 4 and 6 (CDK 4/6) inhibitors, ribociclib, and palbociclib, in combination with endocrine therapy in patients with hormone receptor-positive and human epidermal growth factor receptor 2-negative metastatic breast cancer. Results: A total of 198 patients treated between 2019 and 2023 were analyzed for progression-free survival, overall survival, and prognostic factors. Very early-onset breast cancer, which is diagnosed before the age of 35, was identified as an independent prognostic factor for poor progression-free survival. Additional factors associated with poorer outcomes included liver metastasis, progesterone receptor negativity, high tumor grade, and the concurrent use of fulvestrant with CDK4/6 inhibitors. Both ribociclib and palbociclib demonstrated similar efficacy, and dose reductions due to treatment-related adverse events did not compromise therapeutic outcomes. Conclusions: This study is the first to focus specifically on the treatment of early-onset breast cancer with CDK4/6 inhibitors, providing critical insights into the unique challenges faced by this patient population. The findings underscore the urgent need for personalized treatment strategies, routine genetic testing, and dedicated clinical trials designed to address the specific needs of these high-risk subgroups. By advancing our understanding of the clinical and molecular landscape of early-onset breast cancer and very early-onset breast cancer, this study lays the groundwork for improving outcomes in these underserved patients through tailored therapeutic approaches. Full article

Background: Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors are the standard of care for hormone receptor (HR)+/human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer in combination with endocrine therapy. However, the real-world efficacy and safety of standard versus reduced doses in elderly patients remain unclear. This study aims to compare the clinical outcomes of standard versus reduced doses of CDK4/6 inhibitors in elderly patients with metastatic breast cancer. Methods: This multicenter retrospective cohort study included 158 patients aged ≥70 years diagnosed with HR+/HER2-negative metastatic breast cancer who received either standard or reduced doses of CDK4/6 inhibitors (Ademaciclib, Ribociclib, Palbociclib) as first-line therapy. Progression-free survival (PFS), overall survival (OS), and adverse events (AEs) were evaluated. PFS and OS were estimated using the Kaplan–Meier method, and comparisons between groups were performed using a log-rank test. Results: Of the total population, 108 patients (68.4%) received the standard dose, and 50 patients (31.6%) received a reduced dose. The standard-dose group had significantly longer median PFS compared to the reduced-dose group (21.3 vs. 15.2 months, p = 0.014), while the median OS did not differ significantly (37.2 vs. 37.2 months, p = 0.103). Subgroup analyses revealed no significant differences in PFS or OS between standard and reduced doses for Ademaciclib and Ribociclib, while Palbociclib at standard dose showed superior PFS (21.9 vs. 12.7 months, p = 0.029) and OS (50.5 vs. 28.6 months, p = 0.026). The incidence of Grade 2–4 AEs was higher in the standard-dose group (74.2% vs. 56.8%, p = 0.044). Conclusions: Dose reduction of CDK4/6 inhibitors, particularly Ademaciclib and Ribociclib, is a viable option in elderly patients, maintaining comparable OS outcomes to standard dosing while reducing the risk of adverse events. Palbociclib at standard dose may offer superior outcomes. These findings support personalized dosing strategies to optimize efficacy and tolerability in frail or elderly patients. Full article

Lung cancer is a leading cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC) is the most prevalent lung cancer subtype. Ciclopirox olamine (CPX), an off-patent fungicide, has been identified as a new anticancer agent. Prexasertib (PRE), a Chk1 inhibitor, is in phase 1/2 clinical trials in various tumors. The anticancer effect of the combination of CPX with PRE on NSCLC cells is unknown. Here, we show that CPX is synergistic with PRE in inhibiting cell proliferation and inducing apoptosis of NSCLC (A549 and A427) cells. Combined treatment with CPX and PRE significantly increased the cell population in the G1/G0 and sub-G1 phases, compared to the single treatment with CPX or PRE. Concurrently, the combined treatment downregulated the protein levels of cyclins (A, B1), cyclin-dependent kinases 4, 6, 2 (CDK4, CDK6, CDK2), cell division cycle 25 B, C (Cdc25B, Cdc25C), and upregulated the protein levels of the CDK inhibitors p21 and p27, leading to decreased phosphorylation of Rb. In addition, the combined treatment increased DNA damage, evidenced by increased expression of γH2AX. In line with this, the combined treatment induced more apoptosis than either single treatment. This was associated with increased expression of DR4, DR5, Fas, and FADD and decreased expression of survivin, resulting in activation of caspase 8 and caspase 3 as well as cleavage of poly (ADP ribose) polymerase (PARP). Taken together, the results suggest that inhibition of Chk1 with PRE can enhance the anticancer activity of CPX at least partly by decreasing cell proliferation and increasing apoptosis in NSCLC cells. Full article

Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors are approved for the treatment of human epidermal growth factor receptor 2 (HER-2)-negative, hormone receptor-positive breast cancer. The cardiovascular toxicity of CDK4/6 inhibitors is not well understood. This study aims to profile the cardiac events associated with CDK4/6 inhibitors. Reports from 2015Q1 to 2024Q1 were obtained from the FDA Adverse Event Reporting System (FAERS). Reports identifying palbociclib, ribociclib, and abemaciclib as the primary suspect were examined for cardiovascular toxicity, including hypertension, cardiac failure, cardiomyopathy, arrhythmia, myocardial infarction, and myocarditis. Signal detection was performed using the proportional reporting ratio (PRR), reporting odds ratio (ROR), and information component (IC). A total of 69,139 reports were analyzed. The median time to adverse events was 69 days (interquartile range [IQR], 18–260 days). Of these, 2065 reports documented cardiac adverse events. Ribociclib and QT prolongation were re-confirmed as a signal (PRR 8.43, ROR 8.65, IC025 2.86). Hypertension and cardiac failure were the most frequently reported cardiovascular toxicities. This study demonstrates that the use of CDK4/6 inhibitors is associated with cardiovascular adverse events, such as heart failure and hypertension. Further research is needed to understand the mechanisms and risk factors contributing to the cardiovascular toxicity of CDK4/6 inhibitors. Full article