In aplastic anaemia, bone marrow stem cells that help produce all types of blood cell are destroyed. Destruction is caused in part by T cells.  T cells are immune cells that circulate around the body and normally protect against infection.  In aplastic anaemia, T cells with the CXCR4 protein on their surface are “post-coded” to enter the bone marrow.  This protein can be blocked by new compound BL-8040, preventing T cells from coming into contact with bone marrow stem cells.  This has the potential to stop stem cell destruction.

 The study

A phase 1b trial is being carried out.  This is the earliest type of clinical trial, testing the compound on a small number of patients.  The main purpose of a phase 1 trial is to find the right dose of the drug, balancing desired effect with side effects.  It is not a rigorous test of how well the treatment works.  In this study, patients with severe aplastic anaemia are being given BL-8040 before standard immune-suppressive treatment and once per month after treatment ends.

 The outcome

8 patients have been treated so far:  1 is too early in the study to analyse and 3 had to stop taking the drug due to allergic reactions.  Of the 4 patients who received a course of the drug, 2 achieved complete remissions. The time to response was about 6 months. Researchers noted some promising changes in characteristics of T cells and are looking into this further. 


It is too early to say whether this drug will be beneficial in aplastic anaemia, but it is encouraging to see new compounds being tested.

The study was led by Kadia T et al. MD Anderson Cancer Center, Houston, USA. 

Summary kindly provided by Dr Laura Jardine, National Institute of Health Research Clinical Lecturer in Haematology, Newcastle University