Effects of Lasofoxifene Versus Fulvestrant on Vaginal and Vulvar Symptoms in Patients With ESR1-Mutated, ER+/HER2-, Metastatic Breast Cancer From the ELAINE 1 Study.

Background: Lasofoxifene, a novel endocrine therapy (ET), showed antitumor activity versus fulvestrant in women with ESR1-mutated, metastatic breast cancer (mBC) that progressed on prior ET (phase 2, ELAINE 1 study). We investigated changes in genitourinary syndrome of menopause (GSM) vulvar-vaginal symptoms with lasofoxifene and how patient/disease characteristics affect baseline vulvar-vaginal symptoms in ELAINE 1.

Methods: Women were randomized to oral lasofoxifene 5 mg/day or IM fulvestrant 500 mg (days 1, 15, and 29, then every 28 days) until disease progression/severe toxicity.

Central Nervous System Metastases in Breast Cancer.

Breast cancer metastasizing to the central nervous system (CNS) encompasses two distinct entities: brain metastases involving the cerebral parenchyma and infiltration of the leptomeningeal space, i.e., leptomeningeal disease.

Results of a patient-level pooled analysis of three studies of trastuzumab deruxtecan in HER2-positive breast cancer with active brain metastasis.

Background: Brain metastases (BMs) are common in human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer, increasing morbidity and mortality. Systemic therapy for BMs can be effective, with the triple combination of trastuzumab, capecitabine, and tucatinib being a potential standard. More recently, intracranial activity of antibody-drug conjugates has been reported, but the size of individual studies has been small.

Abemaciclib Plus Fulvestrant in Advanced Breast Cancer After Progression on CDK4/6 Inhibition: Results From the Phase III postMONARCH Trial.

Purpose: Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) combined with endocrine therapy (ET) are the standard first-line treatment for hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC); however, disease progression occurs in almost all patients and additional treatment options are needed. Herein, we report outcomes of the postMONARCH trial investigating a switch in ET with/without CDK4/6 inhibition with abemaciclib after disease progression on CDK4/6i.

Methods: This double-blind, randomized phase III study enrolled patients with disease progression on previous CDK4/6i plus aromatase inhibitor as initial therapy for advanced disease or recurrence on/after adjuvant CDK4/6i + ET.

Practical treatment strategies and novel therapies in the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway in hormone receptor-positive/human epidermal growth factor receptor 2 (HER2)-negative (HR+/HER2-) advanced breast cancer.

Mutations in the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway occur in 30%-40% of patients with advanced hormone receptor-positive/human epidermal growth factor receptor 2 (HER2)-negative (HR+/HER2-) breast cancer. For most patients, endocrine therapy with a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor is the first-line treatment. Recent studies indicate that adding inavolisib, a PI3Kα inhibitor, to palbociclib/fulvestrant benefits patients with endocrine-resistant HR+/HER2- metastatic breast cancer with a PIK3CA mutation.