Kareem has leukemia!

Almost exactly 10 years ago, I was attending my first meeting of the American Society of Hematology as an employee of the American Cancer Society. But, instead of attending meetings, I spent much of my time on the phone with reporters. It was at that meeting that the results were reported of the first clinical trials in patients with chronic myelogenous leukemia (CML) of imatinib, the drug later named Gleevec. Because the results were so outstanding they became national news and as the “expert” at the ACS, I was asked to talk to reporters who dialed the ACS number for information.

Great “breakthrough” drugs for treating cancer rarely live up to their press hype. This one did. Before Gleevec became standard therapy for CML, the diagnosis was a death sentence. The term chronic meant that instead of killing patients in one years as most acute leukemias do, it took around 5 years for CML to do the deed. But still, it did. Newer drugs had extended the time from 3 to 5 years, but still this was no great deal, particularly since many of the patients with CML tend to be younger than the average cancer patient – often in their 40s and 50s.

The newer treatments also turned out to be devastatingly toxic and led to severe fatigue in the patients who took them. But if you are young and have a family, you struggle on with the treatment. Now here comes this drug with almost no side effects, a pill taken once or twice a day, and it causes the disease to disappear. It truly fell into the category of miracle drugs and also became a hopeful harbinger of a new era in cancer treatment called targeted therapy.

Targeted therapy differs from chemotherapy the way a car bomb differs from an assassin’s bullet. Chemotherapy is a car bomb. It kills normal cells along with the cancer cells – just fewer of them. Targeted therapy aims at a specific site on the cancer cell that is responsible for its growth. CML has that site. Somehow, in the DNA molecules of patients with CML, a mistake has occurred and two chromosomes have gotten tangled up so that two specific genes that are supposed to be kept far apart, now sit next to each other. This leads to the production of a protein that acts as an accelerator for the growth of these cells and the development of the leukemia.

Gleevec blocks this protein so it can’t do its job and so the cells don’t proliferate anymore. Cancer researchers have used this model to look for other drugs that target abnormal growth-promoting proteins and they have found some. But none work nearly as well as does Gleevec.

Right now, a person with CML taking Gleevec has a 90 percent chance of being alive after 8 years (remember the drug has only been available for 10 so there isn’t much information on longer use). One problems with the drug is that it must be taken continuously – stop the drug and the leukemia comes back. A second is that the cells can become resistant to it. Fortunately, newer more powerful versions of Gleevec have been developed and they can often reverse this resistance.

Obviously it is better not to have this disease, and I am sure Kareem, one of my favorite basketball players of all time, can’t be happy about it. Still we have come a long way and with a little luck, he will live out his normal life span.