Active, not recruiting • Phase III • Stage IV • ER positive • PR positive • HER2 negative • Medical Oncology • Post-Menopausal • Interventional

The following is imported from ClinicalTrials.gov:

A Comparative Study of AZD9833 Plus Palbociclib Versus Anastrozole Plus Palbociclib in Patients With ER-Positive HER2 Negative Breast Cancer Who Have Not Received Any Systemic Treatment for Advanced Disease

Brief Summary

The study is intended to show superiority of AZD9833 in combination with palbociclib (a CDK4/6 inhibitor) versus anastrozole (an aromatase inhibitor) and palbociclib as the initial treatment of patients with hormone receptor-positive (ER-positive), human epidermal growth factor 2-negative (HER2-negative) advanced/metastatic breast cancer. INFORMATION FOR TRIAL PARTICIPANTS In this trial, the researchers will look at how well camizestrant with palbociclib works, compared with anastrozole with palbociclib, in participants with breast cancer that has either spread into other parts of the body at the time of diagnosis, or has come back after at least 2 years of standard endocrine treatment. Participants in this trial will have breast cancer that has ER proteins but does not have overexpression of HER2 protein.

Description

A Randomised, Multicentre, Double-Blind, Phase III study will evaluate the safety and efficacy of AZD9833 (next generation oral SERD) in combination with palbociclib versus anastrozole in combination with palbociclib for the treatment of patients with ER-positive breast cancer. The goal of the study is to demonstrate superiority of AZD9833 over anastrozole in the context of combination with palbociclib in first line setting. INFORMATION FOR TRIAL PARTICIPANTS Researchers are looking for a better way to treat breast cancer. In people with cancer, some cells have grown out of control to form tumours. The trial drugs palbociclib, camizestrant, and anastrozole are designed to work by blocking the cancer's ability to grow. Camizestrant is also called AZD9833. Palbociclib and anastrozole are already available as treatments for people with certain type of breast cancer. In this trial, the researchers want to find out how well taking camizestrant with palbociclib, or anastrozole with palbociclib, works in participants with breast cancer that has ER proteins but does not have overexpression of HER2 protein. The researchers will look at which trial treatments help the participants live longer with cancer before it gets worse. The trial will split participants into 2 groups: Participants in Group 1 will take camizestrant, palbociclib, and a placebo matched with anastrazole. Participants in Group 2 will take anastrozole, palbociclib, , and a placebo matched with camizestrant. A placebo looks like a treatment but does not have any medicine in it. A computer program will be used to randomly choose the treatments each participant gets. This helps make sure the groups are chosen fairly. Researchers do this so that comparing the results of each treatment will be as accurate as possible. The participants will take their trial treatments in periods called "cycles". Each cycle will last 28 days. During each cycle, the participants will take: camizestrant or anastrozole once daily by mouth palbociclib once daily by mouth for 21 days. Then, they will not take any palbociclib for 7 days Some participants will also get either goserelin or leuprorelin once every month. Participants could get goserelin or leuprorelin if: They are medically determined yet to reach menopause status They are male They will get this treatment as an injection under the skin or into a muscle. Goserelin and leuprorelin work by decreasing the amount of sex hormones made by the body which will lead to reduction of ER production. This can help stop breast cancer from growing. Participants will take trial treatment until the cancer gets worse or they leave the trial. Participants will visit their trial site several times throughout the trial. At these visits, the trial doctors will check the health of the participants. They will also take blood samples and do scans of the participants' tumors.