L-glutamine plumps up sickle-shaped blood cells and prevents blood vessel blockage, say the researchers

US National Human Genome Research Institute

A treatment that reduces the number of blood cells deformed by sickle cell anaemia has passed early tests in people and will soon begin phase III clinical trials.

The trials, which will look at safety and efficacy in a large number of people, were approved in April by the US Food and Drug Administration (FDA) and should begin in September.

Sickle cell anaemia is a hereditary blood disorder for which there is no known cure. The experimental treatment is a pill form of the naturally-occurring amino acid L-glutamine, which plumps up red blood cells deformed by the disease making them less likely to block small blood vessels and cause debilitating pain, says Yutaka Niihara, principal investigator at the Los Angeles Biomedical Research Institute (LA BioMed), where the treatment is being developed.

"In our phase II clinical trial we observed an excellent safety profile and positive trends in reducing the number of crises and hospitalisations in sickle cell disease patients," said Niihara in a press release.

Few other treatments for this disorder have progressed to Phase III.

But the price of the drug is likely to be an issue in developing countries where medication is most needed. The cost of using L-glutamine to treat another disease — short bowel syndrome — is around US$600 per month per patient and Niihara expects initial costs to be similar for sickle cell anaemia.

But he is keen for L-glutamine to be made affordable in developing countries — particularly in Africa where the disease is most prevalent.

"For Africa we would like to plan something via a non-profit organisation so it will be more easily available to people without resources," Niihara told SciDev.Net.

L-glutamine is already sold commercially in many pharmacies in the developed world and it is often sold as a sports supplement. In the LA BioMed trials, however, patients are being given a more concentrated, pharmaceutical–level dose of the amino acid.

Joseph Ojobi, a consultant at the Jos University Teaching Hospital in Nigeria, says the research suggests that sickle cell patients who switch to a protein-rich diet might also be able to alleviate some of their symptoms as protein is a good source of L-glutamine.

But he warns that dietary changes cannot alter the mutated gene that causes sickle cell anaemia and might not alleviate all the symptoms.