Breast Cancer—Metastatic

Yeon Hee Park, Seock-Ah Im, Kyunghee Park, et al.
The study authors conclude that their study identified prognostic biomarkers as well as post-treatment enrichment of homologous recombination deficiency-related genomic scars and frequent switching into molecular subtypes with aggressive and estrogen independence characteristics. Clinical trial information: NCT03401359.
Javier Pascual, Miguel Gil-Gil, Christoph Zielinski, et al.
The study authors conclude that high tumor CCNE1 mRNA expression identified patients with relative resistance to palbociclib plus fulvestrant. This validates prior observations but without statistical significance for interaction. Assessment of Cyclin E1 protein expression did not show predictive value. Clinical trial information: NCT02028507.
Fabrice Andre, Amit Aggarwal, Xi Rao, et al.
The study authors conclude that their findings describe clinical characteristics and specific genomic alterations noted after progression on CDK4 & 6i +/-endocrine therapy. 
Kimberley T Lee, Elaine Chiao, David Lim, et al.
The study authors identified disparities in the use of CDK4/6i for the first-line treatment of metastatic breast cancer. The observed lower use among patients who received care at the urban Baltimore city site with a trend towards lower use among patients from lower-income neighborhoods. This highlights potential barriers with accessing oral cancer therapies - cost, patient distrust, and/or systemic bias.
Komal L. Jhaveri, Valentina Boni, Joohyuk Sohn, et al.
The study authors conclude that Single-agent giredestrant - a highly potent, nonsteroidal oral selective ER degrader - was well tolerated at all doses. There were no dose-limiting toxicities observed and adverse events were generally low grade and in keeping with expected adverse events for endocrine therapies. Clinical activity was observed at all doses. Clinical trial information: NCT03332797.
Erika P. Hamilton, Judy S. Wang, Timothy J. Pluard, et al.
The study authors conclude that the selective, small molecule covalent antagonist of ERα H3B-6545 has a manageable safety profile and demonstrated single-agent anti-tumor activity in heavily pretreated ER+, HER2- mBC patients. Clinical activity was observed in patients with ESR1 mutations. Clinical trial information: NCT03250676.
Huiping Li, Hanfang Jiang, Yongmei Yin,  et al.
GT0918 is a new chemical entity of AR antagonist with possible AR down-regulation. The study authors conclude that this drug has been shown to be well tolerated and may provide potential clinical benefits to androgen receptor-positive metastatic breast cancer patients. This study demonstrated triple-negative androgen receptor-positive patients had more benefit. Clinical trial information: NCT04103853.
Carlo Palmieri, Hannah M. Linden, Stephen Birrell,  et al.
Enobosarm is a novel oral selective androgen receptor (AR) activating agent in which a higher percentage of AR staining correlates with a greater antitumor activity. The study authors conclude that by targeting and activating AR, enobosarm may represent a new hormone treatment approach for AR+/ER+ MBC. Clinical trial information: NCT02463032.
Marietta Scott, Michel Erminio Vandenberghe, Paul Scorer,  et al.
The study authors show that HER2 IHC1+/2+ (ISH-) by Ventana 4B5 represent a significant proportion of breast cancer patients and more than 50% of ER+ve and PR+ve subtypes. The study demonstrated that the 4B5 assay classed several patients as IHC1+/2+ that are IHC0 by Herceptest, but almost all patients IHC0 by 4B5 were also IHC0 by Herceptest.
Jiayu Wang, Yunjiang Liu, Qingyuan Zhang, et al.
The study authors conclude that RC48-ADC showed consistent efficacy in HER2-positive and HER2-low expressing subgroups. It was demonstrated, that the 2.0 mg/kg Q2W showed a more favorable benefit-risk ratio than other dose levels. No new safety signals were observed. Clinical trial information: NCT02881138; NCT03052634.
Peter Schmid, Seock-Ah Im, Anne Armstrong, et al.
The study authors conclude that durvalumab + paclitaxel demonstrated a tolerable safety profile and response rate as expected for a 1st-line triple-negative breast cancer IO/taxane combination. Durvalumab + trastuzumab deruxtecan showed promising early safety and efficacy in 1st-line HER2-low–expressing triple-negative breast cancer; Clinical trial information: NCT03742102.
Xichun Hu, Jian Zhang, Rujiao Liu, Shuiping Gao, et al.
The study authors conclude that A166 - an antibody-drug conjugate composed of a novel cytotoxic drug (Duo-5, anti-microtubule agent) - had a manageable safety profile and high stability in the circulation with much lower acute hematological and gastrointestinal toxicities in terms of incidence rate and grade. The drug demonstrated promising antitumor activity with clinically meaningful responses in heavily pretreated subjects with HER2-positive breast cancer. Clinical trial information: CTR20181301.