A trial looking at a drug called dostarlimab for people with advanced cancer

Please note - this trial is no longer recruiting patients. We hope to add results when they are available.

Cancer type:

All cancer types
Secondary cancers




Phase 1
This trial is for people with cancer that has spread or continued to grow despite other treatments (advanced cancer). 
The first part of the trial is closed. Doctors are looking for people to join the 2nd part of this trial.
The 2nd part of this trial is for people with 1 of the following types of advanced cancer: 
  • womb (endometrial) cancer
  • non small cell lung cancer (NSCLC)
  • a type of cancer that has a specific change in the DNA called microsatellite instability (MMR/MSI)  

More about this trial

For advanced cancer you usually have chemotherapy. This uses cytotoxic drugs to kill the cancer. 
In this trial, doctors are looking at another type of cancer treatment called immunotherapy. It stimulates the immune system to fight the cancer. 
Dostarlimab (also known as TSR-042) is a type of immunotherapy called a monoclonal antibody. It works by attaching to a protein called PD-1 on the surface of cancer cells. This helps the immune system to recognise and attack the cancer. 
Everyone taking part in this trial has dostarlimab. The main aims of this trial are to:
  • learn more about the side effects of dostarlimab 
  • find out how well dostarlimab works as a treatment for advanced cancer

Who can enter

The following bullet points list the entry conditions for this trial. Talk to your doctor or the trial team if you are unsure about any of these. They will be able to advise you. 
Who can take part
You may be able to join this trial if all of the following apply. You:
  • have cancer that has spread or continued to grow despite other treatments (advanced cancer)
  • have satisfactory blood test results
  • are well enough to carry out your normal activities apart from heavy physical work 
  • are willing to have a sample of tissue taken (biopsy) if there isn’t a suitable sample available and you are going to take part in the 2nd part of this trial
  • are willing to use reliable contraception during treatment and for 5 months afterwards if there is any possibility that you or your partner could become pregnant
  • are at least 18 years old
As well as the above, 1 of the following must also apply. You have advanced:
As well as the above, there are other entry conditions that will affect whether you can join the 2nd part of this trial. It depends on the type of cancer you have and what treatment you have already had. Your doctor can tell you more about all the entry conditions that will apply to you. 
Who can’t take part
You cannot join this trial if any of these apply. 
Cancer related
  • have cancer spread in your brain, spinal cord or the membranes that surround the brain (carcinomatous meningitis)  
  • have had dostarlimab or any other similar drug 
  • have had another cancer in the last 2 years apart from carcinoma in situ of the cervix or non melanoma skin cancer that has been successfully treated  
  • have had chemotherapy or targeted drugs in the past 3 weeks
  • have had radiotherapy in the past 3 weeks unless it was radiotherapy to help with symptoms (palliative radiotherapy)
  • have moderate or severe side effects from previous treatment with chemotherapy, radiotherapy or surgery  
Medical conditions
  • have an infection that needs treatment that reaches your whole body (systemic treatment)
  • have taken part in a clinical trial or have had an investigational treatment in the past month
  • had drugs that damp down your immune system (immunosuppressants) in the last week 
  • have an autoimmune disease that needed systemic treatment in the last 2 years, apart from treatment to replace something that the body makes such as thyroxine 
  • have lung problems such as interstitial lung disease 
  • have heart problems such as an irregular heart beat (arrhythmia) or you have had a heart attack in the last 3 months
  • have fits (seizures) that aren’t controlled 
  • drink an amount of alcohol or take an amount of drugs that are a concern for your doctor
  • have HIV
  • have hepatitis B or hepatitis C 
  • have any other medical condition that the trial team think could affect you taking part 
  • are pregnant or breastfeeding 
  • have had a live vaccine in the past 2 weeks 
  • are sensitive to dostarlimab or anything it contains

Trial design

This is an international phase 1 trial. Researchers hope that around 680 people worldwide will take part. 
This trial is in 2 parts. In part 1 researchers looked for the best dose of dostarlimab. This part is now closed. Researchers are now looking for people to join part 2.  
In part 2 doctors want to find out how well dostarlimab works as a treatment. Everyone has the best dose of dostarlimab found during part 1.
You have dostarlimab as a drip into a vein every 3 weeks. This continues for 12 weeks (3 months). You then have dostarlimab every 6 weeks. It takes about 30 minutes each time. 
You continue to have treatment for as long as it is helping you and the side effects aren’t too bad. 
Blood tests
You have extra blood tests as part of this trial. You have them before the start of treatment and at set times during the trial. 
Doctors want to:
  • find out what happens to dostarlimab in your body
  • look for proteins in the blood that can help doctors to find out how the cancer responds to treatment
Tissue sample
The trial team will ask to use a tissue sample of your cancer taken at the time of your diagnosis or during any treatment you have had. 
You need to have a tissue sample taken (a biopsy) if there isn’t a suitable sample available. 
Doctors want to look:
  • at the cancer DNA 
  • for changes in a gene called POLE 
  • for microsatellite instability (MMR/MSI)   

Hospital visits

You see a doctor and have some tests before starting treatment. The tests might include: 
  • a physical examination
  • blood tests
  • urine test
  • heart trace (ECG)
  • a CT scan or MRI scan 
During treatment, you see the trial team every 3 weeks. You have blood tests and a physical examination each time you see them. They will ask you questions about your health. This continues for 3 months. You then see them every 6 weeks. 
You have a CT scan or MRI scan 3 months after the start of your treatment. You then have a CT scan or MRI scan:
  • every 6 weeks for 9 months
  • then every 12 weeks 
This continues for as long as the treatment is helping you and the side effects aren’t too bad. 
After you finish treatment, you see the trial team after a month. You then see or speak with the trial team:
  • after 2 months
  • then every 3 months

Side effects

The trial team monitor you during the time you have treatment and afterwards. You have a phone number to call them if you are worried about anything. The team will tell you about all the possible side effects before starting the trial. 
The most common side effects of dostarlimab are:

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Dr Ellie Im

Supported by


Cancer Research UK trial number


If you have questions about the trial please contact our cancer information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Last reviewed:

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