A Phase IB Study of Pretreatment with Obinutuzumab Followed by Cibisatamab plus Atezolizumab Immunotherapy to Treat Metastatic Colorectal Cancer


Full Title

A Phase Ib, Multicenter, Open-label Study to Evaluate the Safety, Efficacy, and Pharmacokinetics of Cibisatamab in Combination with Atezolizumab After Pretreatment with Obinutuzumab in Patients with Previously Treated Metastatic, Microsatellite-stable Colorectal Adenocarcinoma with High CEACAM5 Expression


The purpose of this study is to find the highest dose of obinutuzumab (as pretreatment) followed by cibisatamab and atezolizumab in patients with metastatic colorectal cancer that continues to grow despite prior treatment. All three drugs are immunotherapies.

Cibisatamab, an investigational drug, is a bispecific antibody, which means it binds to two different proteins: one called CEACAM5 on the surface of some colorectal cancer cells and another on T cells called CD3. Cibisatamab may increase the immune system’s ability to fight cancer by activating T cells to kill the tumor.

Obinutuzumab targets a protein called CD20, which is found on the surface of white blood cells called B cells, and may prime the immune system when given before the other two medications. Atezolizumab is used to treat several cancers and works by boosting the ability of the immune system to detect and destroy cancer cells. All three medications are given intravenously (by vein).


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

  • Patients must have metastatic colorectal cancer that persists despite prior treatment that included a fluoropyrimidine, irinotecan, and oxaliplatin.
  • At least 4 weeks must pass between the completion of prior treatment and the receipt of the study treatment.
  • 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.
  • This study is for patients age 18 and older.

For more information about this study and to inquire about eligibility, please contact Dr. Neil Segal at 646-888-4187.





Disease Status

Relapsed or Refractory