An experimental vaccine that boosts the immune system has produced good results in treating patients with chronic myeloid leukaemia (CML), Italian scientists said on Friday.

Treatment of the condition - a slow-progressing cancer in which too many white blood cells are made in the bone marrow - was revolutionised in 2001 with the approval of Novartis AG’s drug Glivec, which is sold as Gleevec in the United States. But that medicine does not eradicate the disease completely, and patients can develop resistance.

Monica Bocchia of the University of Siena and her colleagues found that a vaccine targeting a protein derived from a faulty chromosome, which is implicated in CML, improved the condition of patients significantly.

A group of 16 patients with stable disease, who were taking either Glivec or interferons, were given six vaccinations of the experimental vaccine. All but one showed an improvement, and seven reached complete cytogenetic remission, with no faulty chromosomes detected during cell division.

“Our preliminary data suggest that the addition of this vaccine to patients treated with conventional treatment might favour further reduction of the residual disease,” Bocchia reported in the Lancet medical journal.

Bocchia said her group was seeking funding for larger randomised clinical trials of the vaccine, which was developed by her scientific team rather than a commercial company.

Both Novartis and Bristol-Myers Squibb Co are working on experimental drugs aimed at patients with CML who no longer respond to treatment with Glivec.