Dec. 6, 2006 -- When first introduced in 2001, Gleevec was hailed as a miracle drug poised to usher in a new age in cancer treatment. Now, five years later, it appears that promise is being fulfilled.
The longest follow-up yet of chronic myeloid(CML) patients treated with Gleevec shows a survival rate of 95% after five years. (The survival rate does not count people who died from causes unrelated to CML or stem-cell transplantation). Before the drug’s introduction, about half of patients died within five years of diagnosis.
And there is more good news. Relapse rates seem to be trending down the longer patients stay on the drug. After three years of treatment, 15% of patients in the study experienced relapses. Two years later, that figure had risen by just 2%.
Gleevec was the first treatment to specifically target cancer cells, leaving healthy cells unharmed. It is marketed by Swiss drug maker Novartis.
The five-year data raise hopes that the novel treatment has turned a deadly leukemia into a largely manageable disease, says Oregon Health & Science University Cancer Institute researcher Brian J. Druker, MD, who led the research team that developed Gleevec.
The findings also bolster hopes that similar drugs will work as well against other cancers. A few of these drugs are already on the market and many more are being investigated.
"My view is that we are at the cusp of a new era in treating cancer," Druker tells WebMD. "Our goal is to convert cancer from a fear diagnosis into a diagnosis that people no longer fear."
Treatment for Life
Gleevec quickly became the treatment of choice for CML after its approval five years ago, and it is now also approved for a specific gastrointestinal cancer and several other rare malignancies.
It does not cure patients of their cancers; it keeps the cancers from growing. Patients taking Gleevec are recommended to maintain treatment for life to help avoid relapse of the disease. It's not yet clear why the drug is not able to cure the disease.
"The hope is that we can take patients with well-controlled disease and cure them, so they no longer need medication," Druker says. "But we are certainly quite happy to have a treatment that controls their disease."
The newly published follow-up included 553 CML patients who were among the first to be treated with Gleevec.
Just 4% of the patients in the study stopped taking the drug because of adverse side effects.
The findings appear in the Dec. 7 issue of The New England Journal of Medicine.
New Concerns About Safety
Until recently, it was thought that Gleevec was largely free of long-term side effects. But a study published last summer raised questions about its long-term safety.
Researchers from Houston’s University of Texas M.D. Anderson Cancer Center presented evidence that the treatment causedin 10 patients who took it. The finding prompted Novartis and the FDA to warn doctors that patients taking the drug should be carefully monitored for signs of heart trouble.
Druker tells WebMD that he has not seen an excess of heart problems in his patients on Gleevec, some of whom have been taking the drug for as long as eight years.
Of the 553 patients in the study, only one developed heart failure that was thought to be related to the treatment, he says.
"If [treatment-related heart problems] occur, our belief is that they are very rare," he says. "And if you balance the benefits vs. the risks, the weight of the evidence favors taking this drug."
There is little argument about that within the medical community.
American Cancer Society spokesman Len Lichtenfeld, MD, calls the introduction of Gleevec "a breakthrough event in the annals of cancer treatment."
"Druker and his colleagues were able to demonstrate that a disease which 30 years ago was considered uniformly difficult to treat and inevitably fatal is now treatable with a drug that is able to produce long, durable and meaningful responses," he says in a news release.