When imatinib (Gleevec) appeared on the market just over 2 decades ago, it revolutionized the treatment of chronic myelogenous leukemia (CML) and transformed it from a grim diagnosis into a largely treatable form of blood cancer. New generations of tyrosine kinase inhibitors (TKIs) have continued to expand options for patients, and many can look forward to normal lifespans.
But these medications cause side effects and can be expensive. Long-term data doesn’t exist for the newer therapies, so no one knows whether they can harm patients over time. None of this is particularly unusual for medications to treat chronic illness, but now there’s a twist:
“Our focus has changed because the results of treatment are so good,” hematologist-oncologist Ehab L. Atallah, MD, of the Medical College of Wisconsin, Milwaukee, said in an interview. “We’re trying to get people off their medication.”
Gleevec: A new age dawns
In the early 1990s, before the era of TKIs, the 5-year relative survival rate from CML was just 27%, and the 10-year rate was only 9.5%, according to a. “If someone showed up with CML, their only option was to go to a bone marrow transplant. About half survived the transplant, and half of those had significant complications from it,” Dr. Atallah said. According to him, just about everyone who didn’t get transplantation would go on to die.
Then came Gleevec, which received Food and Drug Administration approval in 2001. It ushered in the era of “targeted” cancer treatment by specifically killing CML cells, instead of relying on traditional chemotherapy’s carpet-bombing approach.
“Gleevec and other TKIs have revolutionized how CML is treated, and patients are now living normal lives,” hematologist-oncologist Catherine Lai, MD, MPH, of the University of Pennsylvania, Philadelphia, said in an interview.
Alan Fahnestock, a 68-year-old retired telecommunications specialist in north-central Washington state, is one of the fortunate patients.
He was diagnosed with CML in 2004 after he underwent a thoracic CT scan in light of his tobacco use. “My GP found something odd in my lungs and referred me to a pulmonologist, who couldn’t figure it out either. He transmitted blood samples to my eventual hematologist/oncologist,” Mr. Fahnestock said in an interview. “It’s not clear to me that anybody ever figured out what the ‘oddity’ was. It has since apparently gone away. But the oncologist ran all the tests and came up with CML.”
Mr. Fahnestock hadn’t noticed any symptoms, although “this is, perhaps, because I tend not to pay a lot of attention to such things, having abused my body fairly severely over the years and having been borderline anemic since I was a kid. I don’t really expect to feel great and am a bit of a fatalist: I just get on with things until I no longer can.”
His physician prescribed Gleevec. “I had no particularly notable side effects, and carried on with my life pretty much as if nothing had happened,” Mr. Fahnestock said. He stayed on the drug for almost 20 years.