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Leukaemia drug tested

Tuesday 3 November 2009

British scientists have “created a new drug that 'kills' leukaemia - even in worst affected adults”, reported the Daily Mail.

Although the Daily Mail’s headline may suggest that this drug has been tested in humans, this was not the case. As explained much further down the article, this research is at a very early stage. In laboratory experiments, the chemical showed some potential as it killed cancer cells that were resistant to existing drug treatments.

However, much more research would be needed to identify how safe and effective this drug is in animals before it could be tested in humans. Many drugs that show promise in the lab are proven unsafe or ineffective in later animal testing.

This is early research and any potential treatment using this chemical is a long way off.

Where did the story come from?

The research was carried out by Dr Anthony M McElligott and colleagues at Trinity College Dublin and other centres in Ireland, Northern Ireland and Italy. It was published in the peer-reviewed journal Cancer Research. The research was funded by Enterprise Ireland, Cancer Research Ireland and the Higher Education Authority of Ireland.

The newspapers correctly reported that the development of this drug is at an early stage and that it may be years before it can be used. However, the Daily Mail ’s headline that the drug “‘kills’ leukaemia – even in worst affected adults” may lead people to believe that this drug has been tested in patients, which is not the case. Headlines in other news sources, such as BBC News and The Daily Telegraph, are more accurate and simply state that the drug has been shown to kill leukaemia cells.

What kind of research was this?

This laboratory study looked at the effects of a chemical called PBOX-15 (pyrrolo-1,5-benzoxazepine-15) on leukaemia cells extracted from people with chronic lymphocytic leukaemia (CLL). The authors say that new treatments are needed for CLL, particularly for patients who do not respond well to existing therapies.

There are many stages in developing and testing potential new drugs. Laboratory studies such as this one are used to identify the effects of the drug on affected cells and tissues. This is important for directing further study but cannot reliably predict what other effects a drug such as PBOX-15 might have in a living body. This study will need to be followed up with research in animals to assess how safe and effective the drug might be in humans.

What did the research involve?

The researchers took blood samples from 55 patiens with CLL who had not yet begun treatment for their condition. From these samples, white blood cells affected by leukaemia were isolated in the laboratory and exposed to PBOX-15  to see whether they died.

The researchers also compared the effects of the chemical with the effects of fludarabine, a chemotherapy drug, on CLL cells. They also carried out experiments to look at the effect of PBOX-15 on normal bone marrow cells taken from three healthy donors.

What were the basic results?

The researchers found that PBOX-15 killed CLL cells in the laboratory. The drug could also kill CLL cells with characteristics normally associated with a poor outcome of the disease.

Comparison testing showed that PBOX-15 was more effective than fludarabine at killing fludarabine-sensitive CLL cells. PBOX-15 also killed CLL cells that had a genetic mutation that made them resistant to fludarabine treatment.

Testing on three donor bone marrow samples found that PBOX-15 was more toxic to CLL cells than to normal bone marrow cells.

How did the researchers interpret the results?

The researchers concluded that PBOX-15 can kill both high-risk and low-risk CLL cells, and shows “significant clinical potential”.


Although the study shows that PBOX-15 can kill isolated human CLL cells in the laboratory, it cannot reliably predict what other effects it might have in a living body.

There are many stages to developing and testing potential new drugs, which can take many years and are not guaranteed to be successful. The early development stages involve laboratory studies such as this one, which are used to identify the effects of the drug on affected cells and tissues. These early tests are important to establish whether future research is worthwhile.

Following the results of this initial study, the drug seems to be a candidate for further research, which would need to identify how safe and effective this drug is in animals before it could be tested in humans.

Analysis by Bazian
Edited by NHS Website

Links to the headlines

New drug 'can kill leukaemia cells resistant to other treatments'

The Daily Telegraph, 3 November 2009

Drug 'can kill leukaemia cells'

BBC News, 3 November 2009

British scientists create new drug that 'kills' leukaemia - even in worst affected adults

Daily Mail, 3 November 2009

Links to the science

McElligott AM, Maginn EN, Greene LM et al.

The novel tubulin-targeting agent pyrrolo-1,5-benzoxazepine-15 induces apoptosis in poor prognostic subgroups of chronic lymphocytic leukemia

Cancer Research 69, 8366, November 1 2009