postMONARCH: A Randomized, Double-Blind, Placebo-Controlled, Phase 3 Study to Compare the Efficacy of Abemaciclib plus Fulvestrant to Placebo plus Fulvestrant in Participants with HR+, HER2-, Advanced or Metastatic Breast Cancer Following Progression on a CDK4 & 6 Inhibitor and Endocrine Therapy

Protocol # :
Breast Neoplasm
Neoplasm Metastasis
Disease Sites
Principal Investigator
Jeselsohn, Rinath, Malka
Site Research Nurses
Abraham, Elizabeth
Beeler, Maureen
Brule, Maurice, N.
Campbell, Margaret
Fleming, Norah, Michelle
Freeman, Stefani, Danielle
Ginter, Lindsey
Hixon, Nicole, R.
Padden, Sarah
Patel, Nikita
Quinn, Caroline
Roche, Kathleen, A.
Rutter, Morgan
Weitz, MaryAnn

Trial Description

This study will evaluate the effect of adding abemaciclib to fulvestrant for the treatment of
hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-)
breast cancer that progressed or recurred after previous treatment with a type of drug known
as a CDK4/6 inhibitor and endocrine therapy. Participation could last up to 5 years,
depending on how you and your tumor respond.

Eligibility Requirements

Inclusion Criteria:

- Have a diagnosis of HR+, HER2- locally advanced or metastatic breast cancer

- Have radiologic evidence of disease progression or recurrence either

- On treatment with a CDK4/6 inhibitor with aromatase inhibitor (AI) as initial
therapy for advanced disease, or

- On/after treatment with a CDK4/6 inhibitor plus endocrine therapy (ET)
administered as adjuvant therapy for early stage breast cancer

- Must be deemed appropriate for treatment with ET

- If female, have a postmenopausal status by natural or surgical means or by ovarian
function suppression

- Have Response Evaluable Criteria in Solid Tumors (RECIST) evaluable disease
(measurable disease and/or nonmeasurable disease)

- Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group scale
(Oken et al. 1982)

- Have adequate renal, hematologic, and hepatic organ function

- Must be able to swallow capsules/tablets

Exclusion Criteria:

- Have visceral crisis, lymphangitic spread, or leptomeningeal carcinomatosis

- Have symptomatic or untreated central nervous system metastasis

- Have received any systemic therapy between disease recurrence/progression and study

- Have received more than 1 line of therapy for advanced or metastatic disease.

- Have received prior chemotherapy for metastatic breast cancer (MBC)

- Have received prior treatment with fulvestrant, any investigational estrogen receptor
(ER)-directed therapy (including selective ER degraders [SERDs] and non-SERDs), any
phosphatidylinositol 3-kinase (PI3K)-, mammalian target of rapamycin (mTOR)-, or
protein kinase B (AKT)-inhibitor