All of the 25 people treated with venetoclax and ibrutinib for 6 months or more in the CLARITY clinical trial responded to treatment. Around a third of these had no detectable chronic lymphocytic leukaemia (CLL) cells in their blood or bone marrow, suggesting they may be able to stop treatment. All of the people in the CLARITY trial had been treated for CLL before.
These results were presented at the annual American Society of Hematology (ASH) meeting in December 2017.
Treatments such as venetoclax and ibrutinib are very effective in treating CLL when taken on their own but they usually need to be taken every day to keep CLL under control. The CLARITY trial results support the idea that combining these treatments could allow the disease to be controlled well enough for treatment to stop.
The side effects were as expected, including serious infections and neutropenia (a shortage of white blood cells called ‘neutrophils’ that fight infection) but these were successfully treated. A problem called ‘tumour lysis syndrome’ that can occur when lots of cancer cells are broken down quickly was successfully avoided with the dosing schedule used and by pausing treatment if blood tests suggested this may occur.
The trial is no longer recruiting participants but treatment is continuing and longer-term results will be reported when they are available.
A larger trial, FLAIR, is now comparing venetoclax and ibrutinib with standard treatment for people with CLL who have not had treatment before.
With thanks to Professor Peter Hillmen, Chief Investigator, and Dr Francesca Yates, Senior Trial Co-ordinator, for reviewing this article.