Novel Therapeutics in Advanced Breast Cancer: A Review of Current Phase I Clinical Trials

Breast Cancer is estimated to account for approximately 15.5% of all new cancer cases in 2024. While the five-year relative survival rate for women with breast cancer has steadily increased to 91.2% from 2014 to 2020, there remains an unmet need for the treatment of high-risk, early-stage breast cancer and advanced breast cancers. There are a number of ongoing Phase I clinical trials to evaluate the safety, efficacy, pharmacokinetics, and pharmacodynamics of novel therapeutics in breast cancer. This review article aims to provide an overview of early phase therapeutics for patients with advanced breast cancer.

There are a number of promising early therapeutics being evaluated for the treatment of breast cancer. Encouraging data from numerous ongoing phase I trials evaluating cyclin-dependent kinase inhibitors (CDKi), such as PF-07220060, selective estrogen receptor degraders (SERDs), such as imlunestrant, and antibody-conjugate drug therapies, such as Dato-DXd, have pushed these drugs into further stages of development.

This article reviews the recently completed and ongoing Phase I clinical trials for novel therapeutics including CDKi therapies, endocrine therapies, and antibody-drug conjugates for the treatment of advanced breast cancer (aBC). Ultimately these novel therapeutics could have an important impact on patients with advanced breast cancer.