Chronic myeloid leukemia is usually treated first with a imatinib (Gleevec) that targets the protein BCR-ABL. If there is a recurrence due to resistance to the imatinib, individuals are then treated with dasatinib (SPRYCEL), which targets in BCL-ABR in a different way. Unfortunately, resistance to dasatinib is now being seen.

A study by researchers led by Charles Sawyers at Memorial Sloan-Kettering Cancer Center suggests that treating patients with both drugs in the beginning might decrease the chance of recurrence or at the very least, increase the time before such a relapse occurs. The authors suggest that treating patients with both drugs at first may prevent the emergence of the drug-resistant forms.

A third drug that can target both dasatinib- and imatinib resistant BCR-ABL is currently in trials.

In the January issue of Blood, a study shows that in rare cases of chronic myelogenous leukemia (CML), treatment with Gleevec can be discontinued.

The researchers think that some patients treated with Gleevec (imatinib mesylate) that go into extended remissions can stop the drug. They add that patients continue strict monitoring for relapse.

Twelve patients were put into remission with Gleevec for over two years. Six of these patients experienced a relapse within five months after being taken off the drug. When Gleevec was restarted, residual disease again declined.

The other six patients remain in remission after nine to twenty four months follow up.

Despite these results the researchers say 'we do not widely recommend imatinib discontinuation at the present time".

I do have a few questions myself that the article did not address:

Does Gleevec have severe side effects that warrants stopping it at all?

Do they think that Gleevec can potentially cure the patient and some might be able to stop treatment all together?

Sprycel is an oral agent that has recently been approved by the FDA. It works by stopping the production of proteins involved in cancer growth.

The American Society of Hematology presented results that stated that treatment with Sprycel (dasatinib) provides better outcomes compared to giving higher doses of Gleevec (imatinib), in patients with chronic myeloid leukemia (CML), who have stopped responding to standard doses of Gleevec.

In the clinical trial the patients were either treated with Sprycel or increased doses of Gleevec to see who had the better response.

Study results indicated:

• Patients who had achieved a major anticancer response with the standard dose of Gleevec initially, achieved a 35 percent complete response to Sprycel, compared with only 7 percent of those treated with the increased doses of Gleevec.
• Patients who did not receive a major anticancer response with the standard dose of Gleevec initially, achieved a 44 percent major anticancer response to Sprycel, compared to only 7 percent of those treated with the increased doses of Gleevec.
• The main side effect of Sprycel was low levels of blood cells, which may be partly corrected with the use of Neulasta.

The research has concluded that Sprycel provides superior responses to increased-doses of Gleevec among patients with chronic-phase CML who have stopped responding to prior Gleevec therapy.

Acute lymphoblastic leukemia (ALL) is uncommon in adults between 15 and 50 years of age but occurs more frequently in individuals over 50 years of age. The Philadelphia chromosome is a specific gene mutation that occurs in about 20 percent of all ALL cases. The Philadelphia chromosome occurs when specific genetic information is switched. Patients who are Philadelphia chromosome positive typically do not respond well to standard therapies.

Researchers want to find new strategies to improve outcomes for Philadelphia chromosome positive ALL patients. Gleevec has shown some anticancer responses in these patients who no longer responded to standard treatments.

According to a study was done and published in the journal Leukemia, the survival at one year was 66 percent for those patients who received chemotherapy and Gleevec. Among comparison subjects the survival at one year was 43 percent.

What also sounded very promising was that the probability of surviving for one year without a relapse was 58 percent for those in the study and only 11 percent among comparison patients.