WEDNESDAY, Sept. 29, 2004 (HealthDayNews) -- The anti-cancer drug Gleevec, highly touted for slowing the progression of chronic myeloid leukemia, also appears to stall a rare kind of skin cancer, a new study finds.
Eight of 10 patients had their disease controlled with Gleevec or with a combination of Gleevec and surgery, according to a report on the research presented Sept. 29 in Geneva at a meeting of the European Organization for Research and Treatment of Cancer.
The skin cancer, dermatofibrosarcoma protuberans (DFSP), is a malignant tumor that grows in the second layer of the skin. The researchers decided to try Gleevec because earlier research had shown that a gene called the platelet-derived growth factor receptor B (PDGFB) was rearranged in DFSP.
The rearrangement involves a translocation between chromosomes 17 and 22, which results in too much PDGFB, and Gleevec inhibits the PDGFB receptor.
In the trial, the 10 patients were given 800 milligrams of imatinib [Gleevec] daily. Among the eight who responded to treatment, two had a complete response. Four had partial responses and required surgery to make them disease-free.
Two other patients had metastatic DSFP with a more complex genetic profile. One, who had a translocation of chromosomes 17 and 22, had a partial response to Gleevec. However, after seven months of treatment, the disease progressed. The other patient did not have the translocation between chromosomes 17 and 22 and did not respond to Gleevec.
Knowing the genetic profile of the tumor will help determine which patients will respond to Gleevec, the scientists pointed out.
Lead researcher Dr. Grant McArthur, head of the Molecular Oncology and Translational Research Laboratories at the Peter McCallum Cancer Centre in Melbourne, Australia, said in a statement that more than 95 percent of DFSP tumors have the translocation between chromosomes 17 and 22.
"It's difficult to be certain based on only one case, which was very high grade and where there was also the possibility that it may not have been a true DFSP, but our patient without the translocation did not respond to imatinib," he said.
"Nevertheless, our data support the use of imatinib where [translocation] is detected, although our findings cannot be used to make any definite statements about tumors with other molecular abnormalities," he added.
"The most important outcome of our study is that molecular analysis of the tumor can be used to predict a patient's response to treatment where the analysis indicates that the pathway targeted by imatinib is activated," McArthur said.
"This use of Gleevec has been reported previously," said Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society. But he added, "The fact that they were able to get such a substantial number of patients under complete control is certainly striking."
Lichtenfeld said the most important part of the study was the use of genetic analysis to determine which patients would respond to Gleevec.
"They were able to link the response to a certain gene profile and predict whether these patients would respond to the treatment or not," he explained.
"I think it's premature to conclude that this is the definitive answer for the treatment of this cancer," Lichtenfeld said. "But it is not inconsistent with what we are seeing in other types of cancer target therapies. We are seeing gene profiles that predict whether or not a particular patient with a particular cancer is going to respond to a particular drug."
Given the costs of these new cancer-fighting drugs, Lichtenfeld sees genetic profiling as the future in determining which drugs will be effective against particular cancers and which patients are most likely to respond to therapy.
More information
The American Cancer Society can tell you more about skin cancer.
