KEYNOTE 051: a phase 1 / 2 trial aiming to test pembrolizumab in children with a solid tumour (including lymphoma) that has come back or is difficult to treat

This is a trial in children and young people under 18 and the information here is aimed at parents and carers. However, you may also find this information useful if you are a young person with a solid tumour (including lymphoma) or you may wish to share this information with your child if you are a parent or carer. 

This trial is now only recruiting people with Hodgkin lymphoma.

Early results have been published for this trial.

Purpose of trial

The aim of the trial is to see if a new drug called pembrolizumab is safe and helpful in treating children who have a solid tumour or lymphoma that is advanced (widespread) or has come back (relapsed) despite previous treatment.

Pembrolizumab is already used to treat adults with some cancers, but researchers think it could be a useful treatment for children and young people with solid tumours, including lymphoma, too.

This trial aims to:

  • see how the body deals with pembrolizumab
  • find the best dose that can be given without causing serious side effects
  • learn more about side effects in children
  • learn more about how effective the drug is in children.

This trial is now only recruiting people with Hodgkin lymphoma.


This trial has 2 parts.

In part 1, the researchers look for the best safe dose of pembrolizumab that your child can have. They give the drug intravenously (through a drip into a vein, or a central line can be used, if your child has one in place). The dose that your child has, and how often they have the drug, may change. The trial doctor can give you more information. The researchers are also looking at side effects, how your child’s body deals with the drug and how well it works in treating your child’s tumour.

In part 2, everyone has the same dose of pembrolizumab. Your child has pembrolizumab every 2 – 3 weeks. Each treatment takes about half an hour.

If the treatment is helping and the side effects are not too troublesome, your child may continue this treatment for up to 2 years.

The researchers need a sample of tumour tissue from everyone who takes part in this trial. If your child has had an earlier biopsy and there is tissue available, they will request it. If not, they may ask for permission to take another biopsy.

Who can enter

Your consultant can give you advice on whether this trial might be suitable for your child.

Around 310 people are needed for this trial.

Your child may be able to enter if:

  • They have an advanced solid tumour or lymphoma and either previous treatment has not worked or there is no treatment available.
  • They have biopsy tissue available or you give permission for them to have another biopsy in order to test the tissue for markers needed for study entry.
  • Their tumour is measurable by the tests used in the trial.
  • They are well enough to get up and at least play quietly or (if older) are able to look after themselves at least some of the time even if they do need frequent help.
  • (If sexually active) They and their partner are willing to use reliable contraception if there is any chance of pregnancy.
  • Their blood and other health test results are satisfactory.
  • They are between 6 months and 17 years old.

Your child will not be able to enter if:

  • They have had any treatment as part of another clinical trial in the 4 weeks before having treatment in this trial.
  • They have had any problems with their immune system or have any treatment to suppress their immune system (including steroid tablets or injections) in the 7 days before treatment in this trial.
  • They have had a stem cell or organ transplant in the past 5 years.
  • They have had treatment with an anti-cancer monoclonal antibody in the last 4 weeks or haven’t recovered from antibody therapy they had had before that.
  • They have had any other cancer treatment in the last 2 weeks before joining the trial or have not recovered from side effects of earlier treatment (excluding hair loss).
  • They have any other type of cancer that is not in remission.
  • They have had an autoimmune disease that needed treatment in the past two years.
  • They have, or have had, inflammation of the lungs that needed treating with steroids.
  • They have an active infection.
  • They have been treated with a similar drug before.
  • They have HIV, hepatitis C or hepatitis B.
  • They have had a live vaccine within 30 days of starting the trial treatment.
  • They are pregnant or breastfeeding.
  • Any of the study drugs are not suitable for them.
  • They have had a bad reaction to any of the study treatments in the past

Further information

More information about this trial is available at