Genomic Complexity Predicts Resistance to Endocrine Therapy and CDK4/6 Inhibition in Hormone Receptor-Positive (HR+)/HER2-Negative Metastatic Breast Cancer.

Purpose: Clinical biomarkers to identify patients unlikely to benefit from CDK4/6 inhibition (CDK4/6i) in combination with endocrine therapy (ET) are lacking. We implemented a comprehensive circulating tumor DNA (ctDNA) analysis to identify genomic features for predicting and monitoring treatment resistance.

Experimental Design: ctDNA was isolated from 216 plasma samples collected from 51 patients with hormone receptor-positive (HR+)/HER2-negative (HER2-) metastatic breast cancer (MBC) on a phase II trial of palbociclib combined with letrozole or fulvestrant (NCT03007979).

A phase II trial of an alternative schedule of palbociclib and embedded serum TK1 analysis.

Palbociclib 3-weeks-on/1-week-off, combined with hormonal therapy, is approved for hormone receptor positive (HR+)/HER2-negative (HER2-) advanced/metastatic breast cancer (MBC). Neutropenia is the most frequent adverse event (AE). We aim to determine whether an alternative 5-days-on/2-days-off weekly schedule reduces grade 3 and above neutropenia (G3 + ANC) incidence.

The Phase II MutHER Study of Neratinib Alone and in Combination with Fulvestrant in HER2-Mutated, Non-amplified Metastatic Breast Cancer.

Purpose: HER2 mutations (HER2mut) induce endocrine resistance in estrogen receptor-positive (ER+) breast cancer.

Patients And Methods: In this single-arm multi-cohort phase II trial, we evaluated the efficacy of neratinib plus fulvestrant in patients with ER+/HER2mut, HER2 non-amplified metastatic breast cancer (MBC) in the fulvestrant-treated (n = 24) or fulvestrant-naïve cohort (n = 11). Patients with ER-negative (ER-)/HER2mut MBC received neratinib monotherapy in an exploratory ER- cohort (n = 5).

Retrospective Analysis of Treatment Patterns and Effectiveness of Palbociclib and Subsequent Regimens in Metastatic Breast Cancer.

Cyclin-dependent kinase (CDK) 4/6 inhibitors are now the standard of care for hormone receptor-positive (HR+), HER2-negative (HER-) metastatic breast cancer (MBC). However, guidelines are lacking regarding their optimal sequencing with other available agents. This study examines physician practice patterns and treatment outcomes of palbociclib and subsequent therapies in a real-world setting.

Neutrophil-to-lymphocyte ratio as a predictor of survival in patients with triple-negative breast cancer.

Purpose: Peripheral blood lymphopenia and elevated neutrophil-to-lymphocyte ratio (NLR) have been associated with poor outcomes in various malignancies. However, existing literature has largely focused on baseline parameters. The aim of this study is to assess the impact of radiation therapy (RT) and chemotherapy on absolute lymphocyte counts (ALC) and NLR in relation to survival outcomes in patients with triple-negative breast cancer (TNBC).

Serum thymidine kinase 1 activity as a pharmacodynamic marker of cyclin-dependent kinase 4/6 inhibition in patients with early-stage breast cancer receiving neoadjuvant palbociclib.

Background: Thymidine kinase 1 (TK1) is a cell cycle-regulated enzyme with peak expression in the S phase during DNA synthesis, and it is an attractive biomarker of cell proliferation. Serum TK1 activity has demonstrated prognostic value in patients with early-stage breast cancer. Because cyclin-dependent kinase 4/6 (CDK4/6) inhibitors prevent G/S transition, we hypothesized that serum TK1 could be a biomarker for CDK4/6 inhibitors.

Neratinib Efficacy and Circulating Tumor DNA Detection of Mutations in Nonamplified Metastatic Breast Cancer.

Based on promising preclinical data, we conducted a single-arm phase II trial to assess the clinical benefit rate (CBR) of neratinib, defined as complete/partial response (CR/PR) or stable disease (SD) ≥24 weeks, in nonamplified metastatic breast cancer (MBC). Secondary endpoints included progression-free survival (PFS), toxicity, and circulating tumor DNA (ctDNA) detection. Tumor tissue positive for was required for eligibility.

NeoPalAna: Neoadjuvant Palbociclib, a Cyclin-Dependent Kinase 4/6 Inhibitor, and Anastrozole for Clinical Stage 2 or 3 Estrogen Receptor-Positive Breast Cancer.

Cyclin-dependent kinase (CDK) 4/6 drives cell proliferation in estrogen receptor-positive (ER) breast cancer. This single-arm phase II neoadjuvant trial (NeoPalAna) assessed the antiproliferative activity of the CDK4/6 inhibitor palbociclib in primary breast cancer as a prelude to adjuvant studies. Eligible patients with clinical stage II/III ER/HER2 breast cancer received anastrozole 1 mg daily for 4 weeks (cycle 0; with goserelin if premenopausal), followed by adding palbociclib (125 mg daily on days 1-21) on cycle 1 day 1 (C1D1) for four 28-day cycles unless C1D15 Ki67 > 10%, in which case patients went off study due to inadequate response.

A Phase I Trial of BKM120 (Buparlisib) in Combination with Fulvestrant in Postmenopausal Women with Estrogen Receptor-Positive Metastatic Breast Cancer.

Purpose: This trial was conducted to determine the maximum tolerated dose (MTD) and preliminary efficacy of buparlisib, an oral pan-class I PI3K inhibitor, plus fulvestrant in postmenopausal women with metastatic estrogen receptor positive (ER(+)) breast cancer.

Experimental Design: Phase IA employed a 3+3 design to determine the MTD of buparlisib daily plus fulvestrant. Subsequent cohorts (phase IB and cohort C) evaluated intermittent (5/7-day) and continuous dosing of buparlisib (100 mg daily).

Localization of a mutant p53 response element on the tissue inhibitor of metalloproteinase-3 promoter: mutant p53 activities are distinct from wild-type.

Missense mutations in the p53 gene have been observed in greater than 60% of all human tumors. Recent evidence indicates that some mutations in p53 arise as the cancer progresses from a benign tumor to a metastatic tumor and that these mutations in p53 actively contribute to the process of cancer progression. Previously, we reported that the expression of the gene encoding the tissue inhibitor of metalloproteinase-3 (TIMP-3) is repressed in cells expressing codons 248 and 281 mutant p53 alleles.