A study looking at immunotherapy before surgery for gestational trophoblastic tumour (RESOLVE)

Cancer type:

Gestational trophoblastic disease (GTD)




Phase 2

This study is looking at the immunotherapy drug pembrolizumab before surgery for gestational trophoblastic tumour Open a glossary item that has not spread.

It is for people who:

  • have had surgery to try and remove a molar pregnancy Open a glossary item but it hasn’t completely gone and 
  • have now developed a type of gestational trophoblastic tumour which is cancer Open a glossary item and
  • are going to have surgery again to try and remove the cancer

More about this trial

A complete molar pregnancy happens when a sperm fertilises an empty egg that contains no female genes. 

In a complete molar pregnancy, no parts of a baby (foetal tissue) form. There is only molar tissue in the womb. Unfortunately, a molar pregnancy cannot develop into a healthy baby.

Molar pregnancies are benign (not cancerous). You have surgery or drug treatment to get rid of the molar tissue. For most people surgery works well. But for some people, not all molar pregnancy cells are removed. This can sometimes mean the cells grow or they can come back.

Doctors describe this as gestational trophoblastic neoplasia (GTN).

Doctors group GTN into high risk and low risk. It is based on a number of factors, including the size of the tumour and if the cancer has spread. Doctors use the risk group to decide what treatment you need to give the best chance of getting rid of the cancer.

You might have chemotherapy for high risk GTN.

You might have chemotherapy or a second surgery for low risk GTN. Chemotherapy can work well for low risk GTN, but it takes some time and has side effects. People living with GTN who have had chemotherapy have said it can impact their quality of life Open a glossary item. Surgery is quicker, but it does not always work as well as chemotherapy.

Researchers would like to improve treatment for people with low risk GTN. They think that the immunotherapy Open a glossary item drug pembrolizumab could work well before surgery. But they aren’t sure. The are doing this study to try and find out.

Pembrolizumab stimulates the body's immune system Open a glossary item to fight cancer cells. It targets and blocks a protein called PD-1 on the surface of certain immune cells called T cells Open a glossary item. Blocking PD-1 triggers the T cells to find and kill cancer cells.

At the moment, doctors use pembrolizumab to treat high risk GTN when chemotherapy is no longer working. But this is the first time that people with low risk disease are having it.

The main aims of the study are to find out:

  • if people are willing to have this treatment for low risk GTN
  • if having pembrolizumab before surgery is safe
  • how well pembrolizumab before surgery works when compared to surgery alone
  • more about how immunotherapy works and why some cancers, including GTN, can escape the immune system

Who can enter

The following bullet points are a summary of the entry conditions for this study. Talk to your doctor or the study 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 gestational trophoblastic neoplasia (GTN). This is after having surgery for a complete molar pregnancy and it did not go away or came back.
  • have human chorionic gonadotrophin (hCG) levels that have either stayed the same for 3 weeks or have been going up for 2 weeks. You have blood tests to check for this hormone Open a glossary item.
  • have a hCG level under 20,000 IU/L. Your doctor will know this.
  • have a molar pregnancy that doctors think is low risk and may respond well to treatment in the study. Your doctor can explain more.
  • are well enough to carry out all your normal activities, apart from heavy physical work (performance status of 0 or 1
  • have satisfactory blood test results
  • are willing to use reliable contraception during treatment and for at least 6 months after your second surgery. This is advice given to everyone, the level of hCG in your blood increases with pregnancy, and this increases the risk of the cancer coming back.
  • are at least 18 years old

Who can’t take part

Cancer related
You cannot join this study if any of these apply. You:

  • have cancer that has spread
  • have had another type of cancer apart from non melanoma skin cancer Open a glossary item within the last 2 years
  • have types of GTN called choriocarcinoma, placental site trophoblastic tumour Open a glossary item (PSTT) or epithelioid trophoblastic tumour (ETT)
  • are not able to have pembrolizumab and surgery because of cancer treatment you have had in the past. Your doctor will know more.

Medical conditions
You cannot join this study if any of these apply. You:

  • have uncontrolled vaginal bleeding
  • have, or have had, an immunodeficiency disorder which causes your body to have a reduced response to infection
  • are having steroid treatment, apart from very small doses, in the week before your first dose of pembrolizumab
  • are having any other medicine which dampens down the immune system in the week before your first dose of the study drug. Your doctor will know which medicines these are.
  • have an active autoimmune disease Open a glossary item which has needed treatment in the last 2 years. You may still be able to take part if you are having medication which replaces what your body would make naturally, such as thyroxine or insulin. Your doctor will know more.
  • have had lung inflammation (pneumonitis) not caused by an infection and you needed steroids. Or you have pneumonitis at the moment.
  • have HIV, have hepatitis B, active hepatitis C or active tuberculosis Open a glossary item

You cannot join this study if any of these apply. You:

  • have any physical conditions, mental health conditions or treatment which means it may be more difficult for you to take part. Your doctor can explain more.
  • have had a solid organ transplant Open a glossary item
  • have had a live vaccine Open a glossary item recently. Please note the current COVID-19 vaccinations are not live.
  • are pregnant

Trial design

This is a phase 2 study. The study team need 20 people to take part.

It is a randomised trial. You are put into a group by a computer. Neither you nor your doctor will be able to decide which group you are in. There are 2 treatment groups. 

You have 1 of the following:

  • group 1 - surgery
  • group 2 - pembrolizumab before surgery

Group 1
You have an internal ultrasound scan to make sure it’s safe for you to have surgery. You don’t take part in the study if surgery is not a good option for you. Your doctor will talk you through the next steps for treatment if this is the case.

Around 2 weeks after having tests to make sure you can join the study you have surgery. 

Group 2
You have 1 dose of pembrolizumab within 3 days of having tests to make sure you can join the study.

You have pembrolizumab as a drip into a vein. It takes around half an hour.

Your team plan your surgery for around 2 weeks after you have pembrolizumab. 

On the day of surgery, you have an internal ultrasound scan to make sure it’s safe for you to have surgery. Your doctor will talk you through the next steps for treatment if it’s not safe to go ahead.

Samples for research
You have blood tests for research before, during and after treatment. The researchers want to use the samples to:

  • learn more about how well treatment is working
  • look for biomarkers Open a glossary item which might help them to understand if treatment works better for some people than others
  • develop and test new cancer treatments in the future

The study team would like to store tissue samples after your second surgery for future research. And they would like to access a tissue sample from your first surgery. They want to use these samples to learn more about GTN and the immune system.

Hospital visits

You see the doctor and have tests before you can take part. These include:

The study team will also look at the results of any tests or scans you had at diagnosis.

You have chance to talk to your surgical team about any questions you have. They discuss with you the risks and benefits of surgery when you sign the consent form Open a glossary item. And they can give you an idea of what recovery will be like.

Group 2 

MRI scans
You might be offered 2 MRI scans if you are in group 2. The study team would like to use the scans to look at your cancer before, and after, you have pembrolizumab. 

You have the first MRI scan when you have tests to see if you can join the trial. You have the second MRI scan 2 days before your second surgery is due to happen.

This part of the study is optional. You can say no to having MRI scans and still take part in the main study.

Between pembrolizumab and surgery
You see the study team:

  • 1 week after pembrolizumab
  • 11 to 14 days after pembrolizumab

You have blood tests and a physical examination at these visits. The team want to see how you are doing after pembrolizumab and before surgery.

Follow up – Everyone taking part

The study team monitor everyone taking part after surgery.

You have blood and urine tests to measure your human chorionic gonadotrophin (hCG) hormone level. You have:

  • blood and urine tests weekly until your hCG level is normal
  • urine tests once a month once hCG has returned to normal, until it’s been a year since surgery

You can do the hCG blood and urine samples at home or locally in your community. You then send the samples back to the study team. Your study team will go through this carefully with you.

You will be contacted by the study team at the hospital after surgery to see how you are getting on. You will hear from them at around:

  • 2 weeks
  • 6 weeks
  • 3 months

You have blood tests for research and talk about any side effects of treatment at each visit. You have a physical examination or blood tests to check your general health at some visits if you are in group 2.

You might have these appointments over the phone. You take research blood kits home if you’re having a phone appointment. They contain everything your local GP or hospital need to take your blood sample. You post the blood samples back to the study team.

Side effects

The study team monitor you during treatment and afterwards. Contact your advice line or tell your doctor or nurse if any side effects are bad or not getting better.

Pembrolizumab can affect the immune system Open a glossary item. This may cause inflammation Open a glossary item and other reactions in different parts of the body. For many people the inflammation and reactions are not too bad. For some people they can cause serious side effects. 

These side effects could happen during treatment or months after treatment has finished. Rarely, these side effects could be life threatening. Your doctor or nurse can explain what these side effects are, the risk of them happening and what to look out for.
If you have any of these side effects tell your doctor or nurse as soon as possible. You should tell them that you are on or have been on an immunotherapy.

The most common side effects of pembrolizumab are:

  • skin problems such as itchy skin, rash or loss of skin colour
  • loose poo (diarrhoea)
  • cough
  • joint, back or tummy (abdominal) pain
  • fever
  • low level of thyroid Open a glossary item hormone, so you may feel tired, gain weight, feel cold, or have constipation Open a glossary item
  • low levels of salt in the blood, so you may feel tired, confused, have a headache, muscle cramps or feel sick

We have more information about pembrolizumab including possible side effects.

Your surgical team will talk with you about the possible side effects of surgery.



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 Ehsan Ghorani

Supported by

Cancer Research UK
Cancer Research UK Imperial Centre: Clinical Trials Section
Imperial College London
NIHR Imperial Biomedical Research Centre

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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