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BRUIN: A phase 1/2 trial of a new treatment called pirtobrutinib in people with relapsed or refractory chronic lymphocytic leukaemia, small lymphocytic lymphoma or other non-Hodgkin lymphoma

This is a phase 1 (early phase) trial of an experimental treatment. Little is known about the safety and effectiveness of this treatment. You might not benefit from the treatment, but the trial will give important information about this new treatment, which could help other people in the future.

Early results from the first 170 people with CLL/SLL to take part in this trial are available.

Purpose of trial

The trial is in three parts. Only the third part of the trial is currently open to people in the UK:

  • The first part of the trial aims to find the best dose of pirtobrutinib to use for people with chronic lymphocytic leukaemia (CLL) or non-Hodgkin lymphoma. This part of the trial has completed.
  • The next part aims to test the safety of pirtobrutinib combined with venetoclax, or with venetoclax plus rituximab, in people with chronic lymphocytic leukaemia (CLL) that has not responded (refractory) or has come back (relapsed) after previous treatment. This part of the trial is taking place in the US.
  • The final part aims to test how well the best dose of pirtobrutinib on its own works in people with relapsed or refractory CLL or non-Hodgkin lymphoma. This part of the trial is open to people in the UK.


Everybody taking part in this trial in the UK has treatment with pirtobrutinib  (also known as LOXO-305). You have it as tablets that you take every day. You are assigned to a group based on the type of lymphoma or CLL you have, and the treatment you’ve had in the past.

  • Pirtobrutinib is a targeted treatment that blocks a protein called ‘BTK’ on B cells (the type of white blood cells that become abnormal in B-cell lymphomas). BTK is part of a pathway that helps B cells to stay alive and divide. Blocking BTK can make B cells die or prevent them dividing. Pirtobrutinib is a tablet that you take by mouth.

Who can enter

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

Around 860 people are needed for this trial.

You may be able to enter the trial in the UK if:

You won't be able to enter the trial in the UK if:

  • You have any health problems that your doctor thinks might make it unsafe for you to have the trial treatment.
  • Your lymphoma is currently affecting your central nervous system (CNS; brain and spinal cord). (You might be able to enter if you have had previous treatment for CNS lymphoma but it is currently under control.)
  • You are being treated for low blood counts due to an autoimmune reaction.
  • You still have significant side effects from your previous treatment.
  • You have a bowel problem that stops you absorbing food properly.
  • You have been treated with LOXO-305 before.
  • You are currently being treated, or have recently been treated, with another anticancer medicine.
  • You’ve had a stem cell transplant or CAR T-cell therapy in the last 60 days.
  • You’ve had major surgery in the last 4 weeks.
  • You’ve had radiotherapy in the last 7 days.
  • You are taking or have taken certain other drugs.
  • You’ve had significant heart disease in the last 6 months.
  • You have HIV.
  • You have any infections that are not controlled by medicine.
  • You have another cancer, unless it is in remission and is expected to stay in remission for at least 2 years.
  • You are pregnant or breastfeeding.
  • You’ve ever had a bad reaction to the ingredients of any of the drugs used in the trial.

Further information

More information about this trial is available at