A More Precise Aim at Cancer

A More Precise Aim at Cancer

In the 4 decades since the US declared the war on cancer there have been just a few notable discoveries. A new type of therapy that targets one tiny aspect of a cancer cell's life is taking aim to save the lives of many.

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Added to Articles on Mon 05/10/2010

Ever since the National Cancer Act became law in 1971, the United States has made the war on cancer a priority. We now know that there are many different reasons why some cells grow uncontrollably and take the lives of more than 1500 Americans every day. In the decades since, there have been a few standing ovations. But a new type of treatment is already causing a shift in how doctors treat cancer.

Much of how we look at cancer treatment today has to do with advancements in molecular biology, a branch of science that looks deep within a cell's inner workings. For one thing, technology has become more sophisticated allowing scientists to map a cell's DNA. When DNA gets damaged, the recipes for chemical signals can get sabotaged and that can make cells misbehave, grow out of control and edge out healthy cells.

Honing in on the unique molecular aspects of cancer cells is at the heart of an amazing new concept in cancer treatment, "targeted therapy". And a growing number of cancer specialists believe that this approach is the future of cancer treatment.

Taking Aim

Targeted therapies are different from traditional cancer therapies. Chemotherapy kills all rapidly dividing cells, healthy or not. The drugs coarse through the blood stream and kill cells that are actively growing and dividing, a hallmark feature of cancer cells, but also one of some healthy cells too. That is why people who receive chemotherapy experience side effects such as hair loss, nausea and gastrointestinal symptoms because the cells of these systems are constantly turning over and dividing making them susceptible to chemotherapy.

Radiotherapy, while a little more precise, also inadvertently kills healthy cells. And even though the radioactive beam is sighted directly above the tumor cells, the beam doesn’t distinguish healthy cells from cancerous ones.

Targeted therapies however are very specific about where they go. They are designed to zero in on a potentially vulnerable aspect of a cancer cell's life. Researchers study features of cancer cells that either don't exist in a healthy cell or are particularly unique to a specific cancer.

Targeted drug therapy can block proteins, enzymes and receptors that fuel cell growth. They can modify mechanisms that turn cell growth on and off, or cause cancer cells to wither away.  Still other targets mimic the body's own immune system as antibodies that recognize and kill something that doesn't belong.

Gleevec

Indication

GLEEVEC^® (imatinib mesylate) tablets are indicated for:

Newly diagnosed adult patients with Philadelphia chromosome–positive chronic myeloid leukemia (Ph+ CML) in the chronic phase. Patients with Ph+ CML in blast crisis (BC), accelerated phase (AP), or in the chronic phase (CP) after failure of interferon-alpha therapy Adult patients with relapsed or refractory Ph+ acute lymphoblastic leukemia (Ph+ ALL) Adult patients with myelodysplastic/myeloproliferative diseases (MDS/MPD) associated with PDGFR (platelet-derived growth factor receptor) gene rearrangements Adult patients with aggressive systemic mastocytosis (ASM) without the D816V c-KIT mutation or with unknown mutational status Adult patients with hypereosinophilic syndrome (HES) and/or chronic eosinophilic leukemia (CEL) who have the FIP1L1-PDGFRα fusion kinase and for patients with HES and/or CEL who are FIP1L1-PDGFRα fusion kinase–negative or unknown Adult patients with unresectable, recurrent, and/or metastatic dermatofibrosarcoma protuberans (DFSP) Patients with KIT (CD117)—positive gastrointestinal stromal tumors (GIST) that cannot be surgically removed, and/or have spread to other parts of the body Adult patients post-surgery who have had their GISTs completely removed

Who should NOT take GLEEVEC

Women who are or could be pregnant. Fetal harm can occur when administered to pregnant women; therefore, women should not become pregnant, as well as be advised of the potential risk to the unborn child if GLEEVEC is used during pregnancy. Women who are breast-feeding should not take GLEEVEC because of the potential for serious adverse reactions in nursing infants. Sexually active females should use adequate birth control while taking GLEEVEC.

Be sure to talk to your doctor and/or nurse about these issues before taking GLEEVEC.

Warnings and precautions

Edema (swelling) and severe fluid retention have occurred. Your doctor will weigh you regularly and manage unexpected weight gain by drug interruption and diuretics. Cytopenias (reduction or lack of certain cell elements in blood circulation) such as anemia, have occurred. Your doctor will perform complete blood counts weekly for the first month, biweekly for the second month, and periodically thereafter. In most cases, your doctor will reduce or interrupt your GLEEVEC therapy; in rare cases, your doctor may discontinue treatment. Severe congestive heart failure and left ventricle dysfunction have been reported, particularly in patients with other health issues and risk factors. Patients with heart disease or risk factors will be monitored and treated for the condition. Severe liver problems (hepatotoxicity) may occur. Your doctor will check your liver function before beginning treatment and continue to monitor liver function as needed. Bleeding may occur. Severe gastrointestinal (GI) bleeding has been reported in patients with newly diagnosed PH+ CML and KIT+ GIST. GI tumor sites may be the cause of this bleeding in KIT+ GIST. GI perforation (small holes or tears in the walls of the stomach or intestine), in some cases fatal, has been reported. In patients with certain conditions associated with high eosinophil levels (eg, HES, MDS/MPD and ASM), beginning Gleevec has been associated with cardiogenic shock/ left ventricle dysfunction Skin reactions, such as fluid filled blisters, have been reported with the use of GLEEVEC. Clinical cases of hypothyroidism have been reported in patients taking levothyroxine replacement during treatment with GLEEVEC. Your doctor should closely monitor your TSH levels. Long-term use may result in potential liver, kidney, and/or heart toxicities; immune system suppression may also result from long-term use. GLEEVEC can cause fetal harm when administered to a pregnant woman. Women should be aware of the potential harm to the fetus.

Important safety information

The following serious side effects have been reported in patients taking GLEEVEC:

Severe fluid retention, which can cause swelling around the eyes or swelling of the lower legs, lungs, and heart; fatal in rare cases Low levels of certain blood cells Heart failure/cardiogenic shock Liver problems Skin blistering Hemorrhage (abnormal bleeding) Low levels of thyroid hormone

Your doctor will check you closely for any side effects to stop more serious complications from occurring. Patients with heart disease or risk factors for heart failure should also be monitored carefully.

GLEEVEC is sometimes associated with stomach or intestinal irritation. GLEEVEC should be taken with food and a large glass of water to minimize this problem. There have been rare reports, including deaths, of stomach or intestinal perforation (a small hole or tear).

Common side effects of GLEEVEC

A majority of patients treated with GLEEVEC experience side effects at some time. Most side effects are mild to moderate in severity. Some common side effects you may experience include:

Fluid retention Muscle cramps or painAbdominal painVomitingDiarrheaHemorrhage (abnormal bleeding)NauseaFatigueRash

Some mild to moderate side effects can be managed with the help of other medicines and advice from your doctor. However, in some cases, your dose of GLEEVEC may be stopped for awhile or may be changed.

Take GLEEVEC exactly as prescribed. Do not change your dose or stop taking GLEEVEC unless you are told to do so by your doctor. If you miss a dose, take your dose as soon as possible, unless it is almost time for your next dose. In this case, your missed dose should not be taken. A double dose should not be taken to make up for any missed dose. You should take GLEEVEC with a meal and a large glass of water.

Be sure to inform your doctor if you are or think you may be pregnant. You should not breast-feed while taking GLEEVEC.

Do not take any other medications without talking to your doctor or pharmacist first, including over-the-counter medications such as Tylenol^® (acetaminophen); herbal products (St. John's Wort, hypericum perforatum); Coumadin^® (warfarin sodium); rifampin; erythromycin; and Dilantin^® (phenytoin). Taking these with GLEEVEC may affect how they work, or affect how GLEEVEC works.

You should also tell your doctor if you are taking or plan to take iron supplements. Patients should also avoid grapefruit juice and other foods which may affect how GLEEVEC works.

Tell your doctor if you experience side effects during therapy with GLEEVEC, including fever, shortness of breath, blood in your stools, jaundice (yellowing of the skin and/or eyes), sudden weight gain, symptoms of heart failure, or if you have a history of heart disease or risk factors for heart disease.

After GLEEVEC's approval, the following adverse events have been reported in patients treated with GLEEVEC: compression of the heart due to increased fluid, GI perforation (holes in the stomach or intestine), and sudden lung failure. These events, including some fatalities, may or may not have been drug related.

Please see the full Prescribing Information.

http://www.gleevec.com/index.jsp?usertrack.filter_applied=true&NovaId=2935376854629484199

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