PersevERA trial

4 October 2021

A study to compare GDC-9545 plus palbociclib versus letrozole plus palbociclib in people with estrogen receptor-positive, HER2-negative metastatic breast cancer (PersevERA trial)


GDC-9545 (also known as giredestrant) is an investigational new drug designed to block the female sex hormone called estrogen that contributes to the growth and progression of estrogen receptor-positive breast cancer.  Investigational means that the drug has not been approved by health authorities for cancer treatment or treatment of any other disease.  Palbociclib (IBRANCE and letrozole the two other drugs being used in this study, are currently approved therapies in New Zealand for estrogen receptor-positive metastatic breast cancer).

The purpose of this study is to compare the effects, good or bad, of GDC-9545 given in combination with palbociclib versus letrozole given in combination with palbociclib, on patients with ER-positive, HER2-negative locally advanced or metastatic breast cancer.   We need to find out which combination works best for ER positive breast cancer that has spread to other parts of the body, find out more about side effects, and how treatments affect quality of life.

Scientific Title:

A Phase III randomized, double-blind, placebo-controlled, multicenter study evaluating the efficacy and safety of GDC-9545 combined with palbociclib compared with letrozole combined with palbociclib in patients with estrogen receptor-positive, HER2-negative locally advanced or metastatic breast cancer. Protocol BO41843


Women and men have the hormone estrogen in their body and estrogen can make some breast cancers grow. These are estrogen receptor (ER) positive breast cancers. Treatment for these cancers are either to block the hormone getting to the cancer cells, or to lower the amount of the hormone in the body. These treatments are called hormone therapy. Giredestant is a new hormone therapy drug. It blocks estrogen from getting to the breast cancer cells.

Letrozole is a hormone therapy for women who have gone through the menopause. It works by lowering the level of estrogen in the body. Palbociclib is a targeted drug called a cancer growth blocker. It works by blocking proteins that cancer cells use to grow and divide. Doctors use palbociclib for breast cancer that has spread to the surrounding tissue or to another part of the body. Researchers think that adding giredestrant to palbociclib might work better for people with ER positive breast cancer that has spread.

Enrolment: Open

Ask your Oncologist if this trial is suitable for you.