FYI: Article: Gleevec Interferes With Bone Growth

[Guest guest]

Hi all,

I thought you might find this of interest. I still get annoyed by

articles that state that Gleevec has minimal to no side effects -- and

then you have studies like this one showing that Gleevec is working in

more ways than thought. Remember when Gleevec first was in development

(us oldbies here) and some of the " experts " said it was so targeted that

it had no effect on other organ systems? Years later, they clearly are

still finding out that is not the case. (Also, note the blurb here about

" protrusion of the eyes " -- Huh??? For pete's sake; someone got

confused.)

~ G.

Cancer Drug Gleevec Can Interfere With Bone Growth

05.10.06, 12:00 AM ET

WEDNESDAY, May 10 (HealthDay News) -- Gleevec, the drug that has brought

life and hope to patients with some otherwise untreatable cancers, can

interfere with bone formation, researchers have found.

It's a side effect, they say, that deserves careful watching but should

not stop use of the medication.

" This is a new type of side effect that we discovered in part because

some of our patents on Gleevec developed low levels of serum phosphate,

a mineral important in bone synthesis and modeling, " said Dr. Ellin

Berman, a member of the leukemia service at Memorial Sloan-Kettering

Cancer Center in New York City. She's also lead author of a paper on the

finding that appears in the May 11 issue of the New England Journal of

Medicine.

" In some patients it developed very quickly, " Berman said. " In some

patients, phosphate levels were very, very low. Then we brought in

kidney specialists and then bone specialists. What we found was

surprising. It had not been described before. "

The patients were being treated for chronic myelogenous leukemia (CML),

a blood cancer whose outlook has been transformed by Gleevec. The drug

has changed the potential life expectancy of CML patients from a few

years to perhaps decades.

The detection of the drug's effect on bone means patients being treated

with Gleevec for either CML or intestinal cancers called

gastrointestinal stromal tumors " have to be screened for abnormalities

of bone, " Berman said. " What Gleevec appears to do is inhibit bone

synthesis and bone remodeling. "

The new finding focused on just 16 patients who were found to have low

serum phosphate levels, and its ultimate importance has yet to be

determined, Berman said. " This suggests that Gleevec may have long-term

effects on bone, not bone marrow but bone structure itself, " she said.

" We are trying to put the entire picture together. Is everyone on

Gleevec at risk, or just some people? Do we need to look at the entire

bone structure? "

But doctors at Memorial Sloan-Kettering are continuing to use Gleevec --

with careful monitoring of bone structure and function. " Bone is a

dynamic organ, which is constantly being made and remodeled, " Berman

said.

Dr. Marshall Lichtman, executive vice president of research and medical

programs at the Leukemia and Lymphoma Society, called the

Sloan-Kettering report " an important observation. It certainly will be

helpful for physicians caring for patients with CML. But what we don't

know yet are the implications of this over the long run. "

Side effects such as the one reported now " are probably predictable,

because we are inhibiting enzymes in normal tissue as well as diseased

tissue, " Lichtman said. " The remarkable thing is how well-tolerated this

drug is, considering that it inhibits the action of critical enzymes. "

Only mild side effects of Gleevec have been reported before, such as

gastrointestinal upset and slight protrusion of the eyes. While the

ultimate impact of the newly reported effect is unknown, " we have to

take steps to prevent any long-term significant bone disease, " Lichtman

said.

Berman said there may even be a positive side to the discovery. " Gleevec

may have a role in disease where bone synthesis and turnover need to be

turned off, " she said. For example, it could be helpful when cells from

a cancer elsewhere in the body move into a bone. Stopping bone synthesis

could help control that problem, she said.