ProT4: a phase 2 trial to test whether giving donor lymphocytes can help prevent lymphoma relapsing after a sibling donor stem cell transplant

This trial aims to find out if giving you a certain type of T lymphocyte or ‘T cell’ (a type of white blood cell that fights infection) from your sibling donor (brother or sister) a few months after a sibling allogeneic stem cell transplant can help reduce complications and prevent your lymphoma coming back.

Purpose of trial

In an allogeneic stem cell transplant, you have chemotherapy. You are then given stem cells to restore your ability to make new blood cells. If you have an allogeneic stem cell transplant using stem cells from your sibling (brother or sister), you are often given lower doses of anti-cancer treatment than if you are given stem cells from a donor who isn’t related to you.

After an allogeneic stem cell transplant, you have immunosuppressive drugs (drugs that dampen down your immune system) to stop graft versus host disease (GvHD), where the donor cells attack your own cells. However, the immunosuppressive drugs also increase your risk of getting an infection. Giving donor T cells a few months after transplant might reduce this risk.

This trial aims to find out if giving you donor T cells can:

  • reduce your risk of infection
  • affect the number of people who get GvHD or how serious it is
  • affect your immune system
  • reduce the risk of your lymphoma coming back.

You can only take part in this trial if your donor agrees to take part as well as they have to be willing to donate the extra T cells.


Participants are randomised to decide whether or not they have extra T-cells after their allogeneic stem cell transplant. For every 2 people who are given extra T cells, 1 person is not. You can’t decide whether or not you have the extra T cells and neither can your doctor. You are told which group you have been randomised to.

Everyone in this trial has an allogeneic stem cell transplant using a regimen (combination of drugs) that includes chemotherapy and an antibody treatment called ‘alemtuzumab’ (MabCampath).

About a month after the transplant, your doctor does tests to see how the treatment has worked. If your lymphoma is in remission (no evidence of lymphoma) you are randomised to either receive extra donor T cells or not. Your donor has to be willing to give extra T cells at this stage.

The extra T cells are given intravenously (into a vein).

Who can enter

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

Around 56 people with lymphoma and other blood cancers are needed for this trial

You may be able to enter if:

  • You have a blood cancer, including any type of non-Hodgkin lymphoma, chronic lymphocytic leukaemia or Hodgkin lymphoma.
  • Your doctor is recommending an allogeneic stem cell transplant using donor cells from your brother or sister.
  • You are having chemotherapy and alemtuzumab as part of your treatment.
  • Your blood and other health test results are satisfactory.
  • You are 18-69.

You will not be able to enter if:

  • You have GVHD after your transplant.
  • Your lymphoma is not in remission after your transplant.
  • You need to continue immunosuppression or have cellular treatments after your transplant. The trial team can advise if this applies to you.
  • You have problems with your liver or kidneys.
  • You are being treated as part of another clinical trial.
  • You are pregnant or breastfeeding.

Further information

More information about this trial is available at