Novartis' cancer therapy Glivec (imatinib) can now be used in Europe to treat certain patients with gastrointestinal stromal tumours (GIST) up to three years after surgery.
The European Commission (EC) has approved an update to the labelling for the drug, which is the current standard of care for stomach cancer, authorising 36 months of adjuvant therapy for adults with KIT (CD117)-positive GIST whose estimated risk of GIST disease recurrence is more than 50 per cent.
Previously, Glivec had only been available in Europe to treat adults with GIST that could not be removed with surgery or had spread to other parts of the body, as well as adults who were at risk of GIST coming back after surgical removal.
The latest approval was based on a trial of 397 patients that compared a 36-month regimen to a 12-month regimen of Glivec to treat KIT+ GIST after surgery.
Results of the study showed that at five years, 66 per cent of patients taking Glivec for three years after surgery were free of cancer recurrence compared to 48 per cent who had received Glivec for only one year after surgery.
Almost all patients in the trial experienced side effects while taking Glivec and 26 per cent of patients in the 36-month group discontinued their treatment for reasons other than GIST recurrence, compared to 13% in the 12-month group.
Overall survival was also improved after five years in patients taking the extended treatment, with 92 per cent of patients using Glivec for three years after surgery alive compared to 82 per cent who had received Glivec for only one year after surgery.
Hervé Hoppenot, president of Novartis Oncology, described the approval as a “key milestone” in the treatment of GIST.
"With this clinical evidence, physicians now have a strong basis for recommending three years of treatment for these patients with KIT+ GIST after surgery," he said.
GIST is a rare cancer of the GI tract that is estimated to affect 5,000 people in the EU each year.
Most cases of the disease are caused by a mutation to the c-kit gene which produces the KIT protein. This protein causes cells in the GI tract to grow and divide when the body needs to produce more.
However, in people with KIT+ GIST, the c-kit gene is constantly signalling the body needs to produce the KIT protein. Glivec works by inhibiting the c-kit gene and blocking the signal to create more abnormal cells with the KIT protein.
In the US, the Food and Drug Administration (FDA) has Glivec under priority review in the extended indication with a decision expected in the first half of 2012.
Glivec, which is also approved in several other cancers including chronic myeloid leukaemia (CML), was Novartis' second biggest drug of 2011 after Diovan, taking in $4.66bn during the year.