Some with leukemia can safely stop Gleevec

Some leukemia patients may be effectively cured by taking modern cancer pills, giving a small minority of patients the option of discontinuing treatment, French researchers said on Wednesday.

It had been thought that chronic myeloid leukemia (CML) would inevitably return if treatment with drugs such as Novartis’s Gleevec, or imatinib, was discontinued.

But an interim analysis of a small French clinical study published in the Lancet Oncology journal found certain CML patients were able to survive without relapse for up to two years after ending therapy.

So-called tyrosine kinase inhibitor drugs like Gleevec, which was introduced in 2001, have transformed the treatment of CML but cost tens of thousands of dollars a year.

Medical experts have been interested in investigating the idea of stopping treatment, rather than continuing indefinitely as is current standard practice, following evidence of diminishing rates of progression in certain patients.

The French study found that of 69 patients who had done well on Gleevec for at least two years and then stopped taking it, 41 percent remained in complete molecular remission (CMR) after one year and 38 percent were clear for up to two years.

Patients in molecular remission no longer produce an abnormal protein responsible for too many white blood cells being made in the bone marrow, which results in leukemia.

“Sustained deep molecular remission, as we have used as an entry criteria for this trial, is not a frequent outcome of imatinib treatment,” Francois-Xavier Mahon of Universite Victor Segalen Bordeaux and colleagues reported.

“Therefore, patients treated with imatinib who are candidates for treatment interruption are rare ... (and) might represent 10 percent of patients.”

Commenting on the findings, Peter Valent of the Medical University of Vienna said the results showed there was now hope for a drug-induced cure in CML, although questions remained as to whether most patients could be cured and what drugs or combinations of drugs were needed.

SOURCE: The Lancet Oncology , November 2010.