A Phase 2 Study of Dostarlimab in People With Previously Untreated Rectal Cancer


Full Title

A Phase 2, Single-Arm, Open-Label Study with Dostarlimab Monotherapy in Participants with Untreated Stage II/III dMMR/MSI-H Locally Advanced Rectal Cancer


The purpose of this study is to see how well dostarlimab immunotherapy works in people with rectal cancer. The people in this study have stage 2 or 3 rectal cancer. Their cancers are also mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H). dMMR and MSI-H cancer can happen when a cell cannot repair mistakes made during the cell division process.

Dostarlimab blocks a protein that normally puts the brakes on the immune system. Releasing this brake boosts the power of the immune system to find and kill rectal cancer cells. Dostarlimab is given intravenously (by vein). If it works well, some people may not need rectal cancer chemotherapy, radiation therapy, and surgery.

Who Can Join

To join this study, there are a few conditions. You must:

  • Have dMMR or MSI-H stage 2 or 3 rectal cancer.
  • Not have had prior treatment for rectal cancer.
  • Be well enough to walk and take care of yourself. You must be able to do activities such as office work or light housework.
  • Be age 18 or older.


For more information or to see if you can join this study, please call Dr. Andrea Cercek’s office at 646-888-4189.




Phase II (phase 2)

Disease Status

Newly Diagnosed


ClinicalTrials.gov ID