Targeted Therapy for Leukemia May Prove a Breakthrough
STI571 also blocks molecular pathways known to be involved in other cancers, and other research teams are currently testing its effectiveness in these other cancers. Druker has tried the drug in another form of leukemia that typically affects children and adolescents, called acute lymphoblastic leukemia, or ALL, with good results.
A team of Finnish researchers led by Heikki Joensuu, MD, PhD, a specialist in oncology and head of the department of oncology at Helsinki University Central Hospital in Finland, has shown the drug is effective in a woman with a gastrointestinal tumor that had started to spread to the liver. STI571 shrank the tumors even though this patient had not responded to any other therapy. Studies on STI571 for CML, ALL, and stomach cancer are published in the April 5 issue of The New England Journal of Medicine.
John M. Goldman, MD, co-wrote an editorial that accompanied these studies. He considers STI571 a real breakthrough in the treatment of CML because it is far more effective than currently available therapy and has far fewer side effects, at least in the short term.
Because the drug has only been used for a couple of years, however, there is no proof that its positive effects are long lasting or that it really lengthens people's lives. Researchers, therefore, must continue to compare STI571 to available therapies for CML, says Goldman. And, he notes, younger, healthier patients might do best with a more radical therapy, like bone marrow transplantation, that is more dangerous but is also known to cure CML when it is successful. Goldman is from the Imperial College School of Medicine in London.
According to Goldman, STI571 is now being tested for patients with lung, prostate, and brain tumors.
And how is Littrell doing? "I got on the [STI571] pills in December ," she says. "I didn't have to have the [second] transplant. I didn't miss any work -- I continued my life in normal fashion. We go snowmobiling in the winter and boating in the summer. ... This drug has just been a miracle. ... It's literally given me a future. My prognosis with a second transplant was 20% chance of survival in the first year." Currently, her long-term prognosis is unclear, but Littrell and her doctor are very optimistic.