FDA Approves 'Breakthrough' Leukemia Drug
In effect, Gleevec has been designed to crank down this biological throttle. "So far, we have evidence from over 1,000 patients that Gleevec reduces that level of cancerous bone marrow and blood ... but it's long-range effect on survival remains to be shown," says FDA Acting Principal Deputy Commissioner Bernard Schwetz, DMV, PhD.
The unknowns are not raining on Gleevec's approval.
"This is a great day for cancer research. For the past 30 years, cancer researchers have tried to identify the critical abnormalities that drive the growth in cancers. ... That approach of understanding cancer at its root can be applied in developing drugs to kill the cancers without harming normal cells -- [that] can now be applied to every single cancer," Drucker tells WebMD.
That, he says, could make cancer treatment as manageable as diabetes, high blood pressure, or elevated cholesterol. However, because every cancer is different, there might have to be hundreds or thousands of targeted molecules against specific tumors.
Nonetheless, some evidence suggests that Gleevec's targeted therapy approach may work in a rare intestinal cancer as well as brain or lung cancers, says Willis.
"What is remarkable about this drug -- its specificity for its molecular target -- also means that its potential utility will be limited to those cancers that have those targets," says Klausner.
Over time, cancer cells also may build up resistance to the specific molecules aimed against them.
"Maybe in the future, we'll combine two or three targeted agents," says Drucker.
Meanwhile, Novartis says it wants to make sure that everyone has access to the life-saving drug, regardless of income. "We are going to put in place a comprehensive patient assistance program so low-income CML patients are not denied therapy," says Daniel Vasella, MD, Novartis' president.
Susan Dreger is already one satisfied customer. She started on Gleevac last June after all else failed, and in three months, she experienced a dramatic difference.
"I went from a hard time getting out bed some days to basically picking up my life where I'd left off four years ago when I was diagnosed [with CML]," she says.
New studies on the effectiveness of Gleevac in solid tumors are set to be presented at next week's meeting of the American Society of Clinical Oncology in San Francisco -- another indication of the potential of targeted cancer therapies.