A trial looking at pembrolizumab for people with non small cell lung cancer (PePS2)

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

Cancer type:

Lung cancer
Non small cell lung cancer




Phase 2

This trial is for people who are not able to be very active. Doctors measure your general health and activity using a scale called performance status Open a glossary item. This trial is for people with a performance status of 2.

More about this trial

People with non small cell lung cancer (NSCLC) sometimes have symptoms from their cancer that can make them less active. They have a lower performance status (or PS) and this often excludes them from taking part in clinical trials.

We know from previous research that pembrolizumab (also called Keytruda) can help people with lung cancer. But most research has been done in people with a good performance status (performance status of 0 or 1).

Pembrolizumab is a type of biological therapy called a monoclonal antibody. It helps your immune system attack the cancer and stops it from growing.

In this trial, doctors want to find out if pembrolizumab can also help people who have a performance status of 2. They are looking for people who are up and about more than half of the day, can look after themselves but who can’t do any work.

The main aims of this trial are to:

  • find out if pembrolizumab can help people with a performance status of 2
  • find out more about how well pembrolizumab works as a treatment
  • learn how well people cope with side effects
  • look for substances that doctors can measure (biomarkers) which might tell them how the treatment is working

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.

You may be able to join this trial if all of the following apply. You

  • Have NSCLC
  • Are willing to have a sample of your cancer taken (a biopsy Open a glossary item) if there is no suitable sample available that doctors can use to test for a marker called PD-L1. If you already had this test done in the past, the trial team will check the result before you start treatment. 
  • Have had all standard treatments Open a glossary item that your doctor thinks it could help you
  • Are well enough to be up and about for at least half of the day (performance status of 2) and this has not changed in the past 2 weeks    
  • Have had a CT scan Open a glossary item of your chest and tummy (abdomen) in the past 28 days
  • Have at least 1 area of cancer that can be seen on a scan and measures at least 10 mm
  • Have satisfactory blood tests results
  • Are at least 18 years old
  • Are willing to use reliable contraception during treatment and for 90 days after the final dose of pembrolizumab if there is any possibility you or your partner could become pregnant

You cannot join this trial if any of these apply.

Cancer related

  • Your cancer has spread to your brain or the tissues (membranes) surrounding your brain (leptomeningeal disease)
  • You have had radiotherapy in the past 4 weeks
  • You have had treatment with chemotherapy or a biological therapy in the past 4 weeks (1 week if it was the drugs erlotinib, gefitinib, afatinib or crizotinib)
  • You have had pembrolizumab or any other drug that affects a protein called PD-1
  • You have moderate or severe side effects from previous cancer treatment  
  • You have had a severe allergic reaction to monoclonal antibodies Open a glossary item in the past
  • You have had another cancer, unless it has been successfully treated and it hasn’t come back in the past 5 years

Medical condition

  • You have had an autoimmune disease Open a glossary item that needed treatment in the past 2 years unless it was treatment to replace something the body makes such as thyroxin or insulin
  • You have taken drugs that damp down your immune system (immunosuppressants) such as steroids in the past 7 days  
  • You have had a blockage in your bowel (bowel obstruction) or other bowel problems (such as diverticulitis) that your doctor thinks makes you at risk of having a bowel obstruction
  • You have an infection Open a glossary item that needs treatment
  • You have had lung problems such as pneumonitis Open a glossary item or your lungs can’t get rid of carbon dioxide Open a glossary item very well (reduced transfer coefficient or KCO)
  • You have a build up of fluid in the abdomen (ascites) or in the layer of tissue between your lungs (pleura) that isn’t controlled by treatment
  • You have HIV
  • You have hepatitis B or hepatitis C
  • You have tuberculosis (TB)
  • You have any other serious medical condition or mental health problem that the trial team think could affect you taking part


  • You have had a live vaccine Open a glossary item in the past 30 days
  • You take or have taken drugs or drank an amount of alcohol that is a concern for your doctors in the past 12 months    
  • You are pregnant or breastfeeding 

Trial design

This is a phase 2 trial. Researchers need about 60 people from the UK to take part.

Everyone taking part has pembrolizumab. You have it as a drip into a vein every 3 weeks. It takes about 30 minutes each time.

You continue to have pembrolizumab for as long as your cancer doesn’t get worse and the side effects aren’t too bad. You can have it for up to 24 months.

Quality of life questionnaires

Everybody taking part completes quality of life questionnaires before starting treatment and then:

  • every time you have pembrolizumab
  • at the end of treatment
  • 28 days after your last treatment

The questionnaires ask about how you have been feeling and how the treatment affects your daily activities.

Blood and poo (stool) samples

You have some extra blood tests as part of this trial. The researchers want to:

  • look for cancer DNA Open a glossary item in your bloodstream (circulating DNA)
  • learn how the treatment works
  • look for chemicals released by your immune system (such as proteins and cytokines Open a glossary item)

You have the extra blood tests before starting the treatment and at set times during the trial.

The study team will also ask you to give a stool sample before starting treatment. They want to look for gut bacteria Open a glossary item, to see if it can change the way the treatment works.

Tissue samples

You may also need to have a biopsy Open a glossary item (sample of your cancer) before you start treatment. This is to check if there is a marker on your cancer called PD-L1.

Researchers can use a sample of your cancer taken in the past (archival tumour sample). If there is not a suitable sample available, the researchers will ask you to have a biopsy.   

They also ask you to have an extra biopsy at the end of your treatment. You do not need to agree to this extra biopsy if you don’t want to. You can still take part in this trial.

Hospital visits

You see a doctor and have some tests before taking part. These tests might include:

  • blood tests
  • urine test
  • heart trace (ECG Open a glossary item)
  • a physical examination
  • a CT scan

You see the trial doctor for blood tests and a physical examination every 3 weeks.

You have a CT scan every 9 weeks while you are having treatment.

This continues for as long as your cancer stays the same and does not get worse. If your cancer gets worse you stop having pembrolizumab.

If you stop having treatment because the side effects are too bad, you have a CT scan every 9 weeks. This continues for as long your cancer doesn’t get worse or until you start a new cancer treatment.

When you finish your treatment you see the trial team:

  • after 28 days 
  • then every 4 weeks, for 6 months

After 6 months the trial team will phone you every 12 weeks to see how you are.

Side effects

The trial team monitor you during the time you have treatment and you will 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 you start the trial.

The most common side effects of pembrolizumab are:

We have more information about pembrolizumab.

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

Professor Gary Middleton

Supported by

Cancer Research UK Clinical Trials Unit (CRCTU)
Institute of Cancer and Genomic Sciences
Merck, Sharp & Dohme
University of Birmingham 

Questions about cancer? Contact our 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.

Over 60,000 cancer patients enrolled on clinical trials in the UK last year.

Last reviewed:

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