A Phase IB/II Study Evaluating Several Immunotherapy-Based Regimens in Women with Progressive Metastatic Breast Cancer


Full Title

CO39611: A Phase Ib/II, Open- label, Multicenter, Randomized Umbrella Study Evaluating the Efficacy and Safety of Multiple Immunotherapy-Based Treatment Combinations in Patients with Hormone Receptor-Positive HER2-Negative Breast Cancer (MORPHEUS-HR+ Breast Cancer)


This study is evaluating the safety and effectiveness of various immunotherapy-based drug regimens for women with metastatic breast cancer that continues to grow despite treatment and is positive for estrogen and/or progesterone receptors (ER and PR) and negative for the HER2 protein. During the first stage of the study, patients will be randomly assigned to receive one of these treatments:

  • Standard treatment with fulvestrant alone
  • Atezolizumab immunotherapy and fulvestrant
  • Atezolizumab and ipatasertib
  • Atezolizumab, ipatasertib, and fulvestrant

Patients whose cancer stops responding to treatment or continues to grow during the first stage of the study may proceed to the second stage, where they will be randomly assigned to receive atezolizumab and bevacizumab along with one of these hormonal therapies: fulvestrant, exemestane, or tamoxifen.

Atezolizumab is an immunotherapy drug designed to improve the immune system’s ability to recognize and destroy cancer cells by blocking PD-L1, a protein made by some cancers. It is approved for treating bladder and lung cancers; its use in this study is investigational. Ipatasertib is an investigational drug designed to block the activated form of Akt, a protein known to promote the growth of cancer cells. Bevacizumab interferes with the development of blood vessels tumors need to grow and spread. Fulvestrant, exemestane, and tamoxifen all inhibit the ability of estrogen to fuel breast cancer growth.

Atezolizumab and bevacizumab are given intravenously (by vein), fulvestrant by injection, and the others by mouth.


To be eligible for this study, patients must meet several criteria, including but not limited to the following:

  • Patients must have ER/PR-positive HER2-negative metastatic breast cancer that has continued to grow despite treatment with a CDK4/6 inhibitor (such as palbociclib, ribociclib, or abemaciclib).
  • Patients must recover from the serious side effects of prior therapies before entering the study, as well as between stages 1 and 2.
  • For stage 1: Patients must be physically well enough that they are fully ambulatory, capable of all self care, and are capable of all but physically strenuous activities. As an example, patients must be well enough that they would be able to carry out office work or light housework
  • For stage 2: Patients must be able to walk and do routine activities for more than half of their normal waking hours.
  • This study is for women age 18 and older.

For more information about this study and to inquire about eligibility, please contact Dr. Elizabeth Comen at 646-888-4525.