Novartis announced new data showing a significant improvement in both recurrence-free survival and overall survival for patients taking Glivec (imatinib) for three years after surgery to remove KIT (CD117)-positive Gastrointestinal Stromal Tumours (GIST) compared to one year of treatment. These data will be presented at the 47th American Society of Clinical Oncology (ASCO) plenary session on Sunday, June 5.

The results show that at five years 66% of patients taking Glivec for three years remained free of cancer recurrence (primary endpoint) compared to 48% who had received Glivec for only one year (p<.0001). Moreover, 92% of patients taking Glivec for three years were alive (secondary endpoint) compared to 82% who had received Glivec for only one year (p=.019). Median patient follow-up was 54 months.

The 400-patient phase III trial, conducted by the Scandinavian Sarcoma Group (SSG) and the Sarcoma Group of the Arbeitsgemeinschaft Internistische Onkologie (AIO), is the first prospective multi-centre clinical trial to demonstrate a survival benefit of adjuvant Glivec therapy for KIT+ GIST with extended three years of therapy relative to one year of therapy. The side effect profile in the clinical trial was consistent with that reported in previous studies with Glivec.

“This study confirms the hypothesis that extending the duration of Glivec treatment for patients following surgery improves recurrence-free survival. For the first time, an effect on overall survival was found,” said Heikki Joensuu, MD, PhD, Professor, Oncology, University of Helsinki and principal investigator of the study. “Results from this trial may positively impact clinical practice by helping physicians create the optimal treatment plan for patients with operable KIT+ GIST.”

GIST are a rare, life-threatening cancer of the gastrointestinal tract. The major cause of GIST is an abnormal form of the protein KIT, which causes cells to grow uncontrollably and become cancerous. Patients with GIST are at risk of recurrence following complete resection of primary GIST.

“Over the past nine years Glivec has provided KIT+ GIST patients with the first effective drug treatment option in the metastatic setting and later in the adjuvant setting,” said Hervé Hoppenot, president, Novartis Oncology. “Now we see exciting new data showing that by extending post-surgical treatment duration to three years, Glivec has significant impact on overall survival in patients with KIT+ GIST. This is important news for GIST patients and the GIST community.”

The SSG XVIII clinical trial was conducted by the Scandinavian Sarcoma Group (SSG), and the Sarcoma Group of the Arbeitsgemeinschaft Internistische Onkologie (AIO). SSG XVIII is a multi-centre, prospective, randomized study for the evaluation of adjuvant treatment with Glivec of histologically verified KIT+ GIST with a greater than 50% risk of GIST recurrence despite complete removal of all macroscopic GIST tissue at surgery.

The primary endpoint of the study was to compare the recurrence-free survival in GIST patients with a greater than 50% estimated risk of disease recurrence within the first five years following the diagnosis and treatment with adjuvant Glivec for 12 or 36 months. The secondary endpoints included overall survival and treatment safety.

Four hundred patients entered the study and the median follow-up was 54 months. Recurrence-free survival was longer in the 36-month group compared to the 12-month group (HR 0.46, 95% CI 0.32-0.65; p<.0001; five-year recurrence-free survival 66% vs. 48%, respectively). Patients assigned to 36 months of Glivec had longer overall survival (HR 0.45, 95% CI 0.22-0.89; p=.019; five-year overall survival 92% vs. 82%, respectively). Glivec was generally well tolerated. The proportion of patients who discontinued Glivec during the assigned treatment period for reasons other than GIST recurrence was 26% in the 36-month group and 13% in the 12-month group.

Glivec is approved in more than 110 countries, including the US, EU and Japan, for the treatment of all phases of Ph+ CML. Glivec is also approved in the US, EU and other countries for the treatment of patients with KIT (CD117)-positive GIST, which cannot be surgically removed and/or have already spread to other parts of the body (metastasized). In the US and EU, Glivec is approved for the post-surgery treatment of adult patients following complete surgical removal of KIT (CD117)-positive GIST.

Not all indications are available in every country and indications may differ.

Glivec can cause fetal harm when administered to a pregnant woman. Women should not become pregnant, and should be advised of the potential risk to the unborn child.

Glivec is often associated with edema (swelling) and serious fluid retention. Studies have shown that edema (swelling) tended to occur more often among patients who are 65 and older or those taking higher doses of Glivec.

Cytopenias (reduction or lack of certain cell elements in blood circulation), such as anaemia, have occurred. If the cytopenia is severe, your doctor may reduce your dose or temporarily stop your treatment with Glivec.

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. Cases of fatal liver failure and severe liver injury requiring liver transplants have been reported with both short-term and long-term use of Glivec.

Bleeding may occur. Severe gastrointestinal (GI) bleeding has been reported in patients with KIT+ GIST. GI tumor sites may be the cause of this bleeding.

In patients with hypereosinophilic syndrome (a condition with increased eosinophils, which are a type of white blood cell) and heart involvement, cases of heart disease (cardiogenic shock/left ventricular dysfunction) have been associated with the initiation of Glivec therapy.

Skin reactions, such as fluid-filled blisters, have been reported with the use of Glivec. Clinical cases of hypothyroidism (reduction in thyroid hormones) have been reported in patients taking levothyroxine replacement with Glivec.

Long-term use may result in potential liver, kidney, and/or heart toxicities; immune system suppression may also result from long-term use.

GI perforation (small holes or tears in the walls of the stomach or intestine), in some cases fatal, has been reported.

Growth retardation has been reported in children taking Glivec. The long-term effects of extended treatment with Glivec on growth in children are unknown.

Cases of Tumour Lysis Syndrome (TLS), which refers to a metabolic and electrolyte disturbance caused by the breakdown of tumour cells, have been reported and can be life-threatening in some cases.

Almost all patients with KIT+ GIST treated with Glivec experience side effects at some time. Some common side effects you may experience are fluid retention, muscle cramps or pain and bone pain, abdominal pain, loss of appetite, vomiting, diarrhoea, decreased haemoglobin, abnormal bleeding, nausea, fatigue and rash.

Glivec is sometimes associated with stomach or intestinal irritation. Glivec 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).

If you are experiencing any of the mentioned side effects, please be sure to speak with your doctor immediately.

Do not take any other medications without talking to your doctor or pharmacist first, including Tylenol (acetaminophen); herbal products (St. John's wort, Hypericum perforatum); Coumadin (warfarin sodium); rifampin; erythromycin; metoprolol; ketoconazole; and Dilantin (phenytoin). Taking these with Glivec may affect how they work, or affect how Glivec 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 that may affect how Glivec works.

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