(RxWiki News) With all the differences that can occur on a molecular level between one person and another, it shouldn't be surprising that a medication may not work as well for everyone.
For most people who have chronic myelogenous leukemia (CML) treatment with Gleevec (imatinib) is successful for preventing the cancer from going into the acute phase, a much more aggressive state of disease. But not everybody responds to Gleevec.
"Ask your doctor about Sprycel."
A long term study led by Neil Shah, MD, PhD, from the University of California at San Francisco showed that Sprycel (dasatinib) was effective for the treatment of chronic myelogenous leukemia if and when Gleevec becomes ineffective.
The six year trial showed that daily dosing of Sprycel caused low levels of side effects over a five year period.
The treatment was effective in reducing acute episodes of the cancer even though the trial focused on patients that did not respond with earlier treatment with Gleevec.
This class of drugs known as BCR-ABL inhibitors targets the specific mutation involved in chronic myelogenous leukemia, although both drugs are slightly different from each other.
Data from a six year period, on a total of 670 patients, demonstrated an overall survival of 78 percent for the patients given Sprycel, with a five percent chance of acute cancer developing.
The study was impressive because many of the patients had not responded to previous treatment with Gleevec.
In comparison, the effectiveness of Gleevec in raising overall survival in new cases of CML has been estimated to vary between 89 and 95 percent, with a 1 percent chance of acute cancer developing.
Initially approved by the U.S. Food and Drug Administration in 2006 for the treatment of chronic myelogenous leukemia that did not respond to treatment with Gleevec, Sprycel is notable for being linked to a rare side effect, causing high blood pressure in the lungs of cancer patient.
More common side effects in about a quarter of the patients in this trial included headache, diarrhea, fatigue and small amounts of liquid in the lungs.
The FDA later granted approval for using Sprycel to treat newly diagnosed cases of chronic myelogenous leukemia in October 2010.
Research presented at conferences should be considered preliminary until publication in a peer-reviewed journal.
Researchers disclosed financial links with ARIAD, Bristol-Myers Squibb, Novartis, Pfizer, IL Yang, Amgen, Chemgenex, Deciphera, Celgene, Genzyme, and Ambit BioSciences.