A Study of Palbociclib in Combination With Fulvestrant or Tamoxifen as Treatment for Metastatic Breast Cancer

Metastatic Breast Cancer Clinical Trial

Official title: Palbociclib in Combination With Fulvestrant or Tamoxifen as Treatment for Hormone Receptor Positive Metastatic Breast Cancer Previously Exposed to Inhibitors of the PI3K Pathway: A Phase II Study With Pharmacodynamics Markers

Status Completed

Clinical Trial Summary

This phase II trial studies the side effects of palbociclib when given together with fulvestrant or tamoxifen citrate in treating patients with hormone receptor positive breast cancer that has spread from where it started to nearby tissue or lymph nodes (locally advanced) or has spread to other places in the body (metastatic). Palbociclib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Hormone therapy using fulvestrant or tamoxifen citrate may fight breast cancer by blocking the use of estrogen by the tumor cells. Giving palbociclib together with fulvestrant or tamoxifen citrate may work better in treating hormone receptor positive breast cancer.

Clinical Trial Description

Patients will be randomly allocated in a 1:1 ratio to take either 100 mg or 125 mg of palbociclib. Randomized treatment assignments will be made by permuted blocks, generated by our collaborating statistician at Dana-Farber Cancer Institute.

PRIMARY OBJECTIVES:

I. To evaluate the incidence of grade 3/4 neutropenia in patients with hormone receptor positive (HR+) advanced breast cancer previously exposed to chemotherapy, treated with fulvestrant or tamoxifen (tamoxifen citrate) in combination with palbociclib at a dose of 100mg or 125mg.

SECONDARY OBJECTIVES:

I. To evaluate progression-free survival with 100 mg and 125 mg dosing of palbociclib.

II. To evaluate inhibition of retinoblastoma (RB) phosphorylation in tumor and in skin at 100 mg and 125 mg dosing of palbociclib.

III. To evaluate the correlation between inhibition of RB phosphorylation in skin and tumor.

IV. To evaluate the correlation between inhibition of RB phosphorylation and progression-free survival (PFS).

V. To evaluate the objective response and clinical benefit rate of palbociclib given at 100 mg or 125 mg.

VI. To evaluate the toxicity associated with palbociclib given at 100 mg and 125 mg in combination with fulvestrant or tamoxifen.

VII. To evaluate markers of resistance to palbociclib and fulvestrant or tamoxifen in circulating plasma tumor deoxyribonucleic acid (DNA) (ptDNA).

OUTLINE: Patients are randomized to 1 of 2 treatment arms.

ARM I: Patients receive low-dose palbociclib orally (PO) on days 1-21. Patients also receive tamoxifen citrate PO on days 1-28 or fulvestrant intramuscularly (IM) on days 1 and 15 of cycle 1 and then on day 1 only in subsequent cycles. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity.

ARM II: Patients receive high-dose palbociclib PO on days 1-21. Patients also receive tamoxifen citrate PO on days 1-28 or fulvestrant IM on days 1 and 15 of cycle 1 and then on day 1 only in subsequent cycles. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. ;

Related Conditions & MeSH terms

• Breast Neoplasms
• Hormone Receptor Positive
• Metastatic Breast Cancer

• NCT number: NCT02384239
• Study type: Interventional
• Source: University of California, San Francisco
• Status: Completed
• Phase: Phase 2
• Start date: October 19, 2015
• Completion date: January 31, 2021