Planned clinical trial of a new drug for aplastic anaemia at King’s College Hospital

King’s College Hospital, London are developing a clinical trial for a new treatment for patients with aplastic anaemia who have not responded to the standard immune suppressing drugs, ATG and ciclosporin. This trial has been made possible due to exciting breakthrough results from the research laboratory at King’s. The new treatment is with a drug called low dose interleukin-2 (IL-2). This drug stimulates a key part of the immune system that is lacking in aplastic anaemia, the T regulatory cells (or ‘Tregs’). King’s plan to give this drug to patients with aplastic anaemia who have not responded to standard treatment, to assess its safety and how effective it is. As part of this clinical trial, they will also be doing a very important research study to examine exactly how IL-2 works in aplastic anaemia.

 

Here is a summary of some information about this drug and the trial.

  1. What is IL-2?

Interleukin -2 (Il-2) is a type of antibody called a ‘monoclonal antibody’, which is a single pure type of antibody. It mostly stimulates particular immune cells (Tregs). It also suppresses other types of immune cells that are too active in aplastic anaemia.

  1. Why do we think it may work in aplastic anaemia?

We know that the immune system in aplastic anaemia is disturbed and destroys bone marrow stem cells, resulting in low blood numbers. Immune suppressing drugs like ATG and ciclosporin work in up to two thirds of patients, but IL-2 has a more specific (targeted) effect on the immune system, especially through increasing Tregs. Recent research in the laboratory at King’s has defined Tregs and their subtypes using the very latest and state of the art technology called ‘CyTOF’ that can examine up to 40 protein markers on single cells. This can also clearly separate out aplastic anaemia Tregs from normal Tregs, and predict which patients will respond to immune suppressing drugs. Importantly, laboratory results shows that IL-2 can increase the numbers of Tregs in aplastic anaemia patients.

  1. Has low dose IL-2 been used before?

Yes. Low dose IL-2 is being used in clinical trials to treat other immune conditions such as diabetes, inflammation of the bowel such as Crohn’s disease, lupus and other types of immune arthritis. Also, at low doses the drug is very safe to give to a patient. IL-2 is given as an injection under the skin (‘subcutaneous’).

  1. Why is there a need for a new drug?

We know that only about a third of patients respond to ATG and ciclosporin, and some patients relapse afterwards. For those who don’t respond, eltrombopag may be available but only just under half will respond to that drug. Some patients may later develop MDS or acute leukaemia. Also, not all patients are able to have a bone marrow /stem cell transplant.

 

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