Active Substance: panitumumab
Common Name: panitumumab
ATC Code: L01XC08
Marketing Authorisation Holder: Amgen Europe B.V.
Active Substance: panitumumab
Authorisation Date: 2007-12-03
Therapeutic Area: Colorectal Neoplasms
Pharmacotherapeutic Group: Antineoplastic agents
Vectibix is indicated for the treatment of adult patients with wild-type RAS metastatic colorectal cancer (mCRC):
- in first-line in combination with FOLFOX.
- in second-line in combination with FOLFIRI for patients who have received first-line fluoropyrimidine-based chemotherapy (excluding irinotecan).
- as monotherapy after failure of fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy regimens.
What is Vectibix?
Vectibix is a medicine that contains the active substance panitumumab. It is available as a concentrate that is made up into a solution for infusion (drip) into a vein.
What is Vectibix used for?
Vectibix is used to treat metastatic cancer of the colon or rectum. This is cancer of the large intestine (bowel) that has spread to other parts of the body. Vectibix is used in patients whose tumour cells contain non‑mutated (wild-type) ‘RAS’. RAS is a group of genes including those known as KRAS and NRAS; when mutated (changed) forms of RAS are present in tumour cells they stimulate tumour growth. About half of the patients with metastatic cancer of the colon or rectum have wild-type RAS tumours. Vectibix is used:
- in combination with ‘FOLFOX’ chemotherapy (oxaliplatin, 5-fluorouracil and folinic acid) as first-line treatment (patients who have not been treated before);
- in combination with ‘FOLFIRI’ chemotherapy (irinotecan, 5-fluorouracil and folinic acid) in patients who have already received fluoropyrimidine-based chemotherapy (excluding irinotecan);
- on its own after treatment has stopped working with combinations of anticancer medicines that include a ‘fluoropyrimidine’ (such as 5‑fluorouracil), oxaliplatin and irinotecan.
The medicine can only be obtained with a prescription.
How is Vectibix used?
Treatment with Vectibix should be supervised by a doctor who has experience in the use of anticancer therapy. It should only be started after the presence of wild-type RAS (KRAS and NRAS genes) has been confirmed by an experienced laboratory using a validated test method.
The recommended dose of Vectibix is 6 mg per kilogram body weight given once every two weeks as an infusion. The recommended infusion time is around 60 minutes, but larger doses may need 90 minutes. The dose may need to be modified if severe skin reactions occur.
How does Vectibix work?
The active substance in Vectibix, panitumumab, is a monoclonal antibody. A monoclonal antibody is an antibody (a type of protein) that has been designed to recognise and attach to a specific structure (called an antigen) that is found on certain cells in the body. Panitumumab has been designed to attach to EGFR, which can be found on the surface of certain cells, including cells in some tumours. As a result, these tumour cells can no longer receive the messages transmitted via EGFR that they need for growth, progression and spreading (metastasis).
Panitumumab does not seem to work in tumour cells that contain mutated RAS. This is because their growth is not controlled by signals transmitted via EGFR and they continue to grow even when the EGFR is blocked.
How has Vectibix been studied?
Vectibix has been studied in three main studies. The first involved a total of 463 patients with metastatic cancer of the colon or rectum whose disease had got worse during or after previous treatment that included a fluoropyrimidine, oxaliplatin and irinotecan. The effects of Vectibix in addition to ‘best supportive care’ were compared with those of best supportive care alone. Best supportive care is any medicines or techniques to help patients, such as antibiotics, painkillers, transfusions and surgery, but not other anticancer medicines. The main measure of effectiveness was progression-free survival (how long the patients lived without their disease getting worse). The results of the study were analysed separately in 243 patients whose tumours contained wild-type KRAS and in 184 patients in whom the KRAS gene contained a mutation.
The second main study involved 1,183 patients with metastatic cancer of the colon or rectum who had not been treated before for their metastatic cancer. Vectibix in combination with FOLFOX chemotherapy was compared with chemotherapy alone. The main measure of effectiveness was progression-free survival.
The third main study involved 1,186 patients with metastatic cancer of the colon or rectum who had been treated before. It compared Vectibix in combination with FOLFIRI chemotherapy with chemotherapy alone. The main measures of effectiveness were progression-free survival and overall survival (the length of time the patients lived).
What benefit has Vectibix shown during the studies?
The patients with wild-type KRAS in their tumours who received Vectibix in addition to best supportive care lived for an average of 12.3 weeks without their disease getting worse. This compared with 7.3 weeks in those who received best supportive care alone. In contrast, there was no effect of Vectibix in the patients with mutated KRAS in their tumours, with both groups of patients living for an average of around 7.3 weeks without their disease getting worse.
In the second study, patients with wild-type KRAS receiving Vectibix in combination with FOLFOX lived for 10 months without the disease getting worse compared with 8.6 months for patients receiving FOLFOX alone. In a more recent analysis of the same study, patients with wild-type RAS receiving Vectibix in combination with FOLFIX lived for an average of 10.8 months without the disease getting worse.
In the third study, patients with wild-type KRAS receiving Vectibix in combination with FOLFIRI lived for 14.5 months compared with 12.5 months in patients receiving FOLFIRI alone. Patients receiving Vectibix also had a longer period of time without their disease getting worse: 6.7 months versus 4.9 months.
What is the risk associated with Vectibix?
In studies, 93% of the patients receiving Vectibix had side effects affecting the skin, although most of these were mild or moderate. The most common side effects with Vectibix (seen in more than 2 patients in 10) are diarrhoea, nausea (feeling sick), vomiting, constipation, abdominal pain (stomach ache), fatigue (tiredness), pyrexia (fever), lack of appetite, paronychia (nail-bed infection), rash, acneiform dermatitis (skin inflammation resembling acne), pruritus (itching), erythema (reddening of the skin) and dry skin. For the full list of all side effects reported with Vectibix, see the package leaflet.
Vectibix must not be used in patients who have had a severe or life-threatening hypersensitivity (allergic) reaction to panitumumab or any of the other ingredients in the past. It must not be used in patients with interstitial pneumonitis or pulmonary fibrosis (lung diseases). Vectibix must not be used with oxaliplatin-containing chemotherapy in patients whose tumour contains the mutated RAS gene or for whom the RAS status is not known.
Why has Vectibix been approved?
The CHMP concluded that Vectibix’s benefits are greater than its risks and recommended that it be given marketing authorisation.
Vectibix has been given ‘conditional approval’. This means that there is more evidence to come about the medicine, in particular its safety and effectiveness in patients whose tumours contain wild-type RAS. Every year, the European Medicines Agency will review any new information that may become available and this summary will be updated as necessary.
What information is still awaited for Vectibix?
The company that makes Vectibix will supply the results of additional studies looking at the safety and effectiveness of the medicine in patients with cancer of the colon or rectum. These include a study to confirm the effectiveness of Vectibix, given on its own, in its approved use.
The company will also collect information to check that patients are adequately tested for RAS mutations.
What measures are being taken to ensure the safe use of Vectibix?
The company that markets Vectibix will ensure that all doctors who are expected to prescribe Vectibix are provided with educational material informing them of the importance of carrying out a RAS test before treatment with Vectibix and only using Vectibix in patients whose tumour is confirmed to contain the wild-type RAS gene.
Other information about Vectibix
The European Commission granted a conditional marketing authorisation valid throughout the European Union for Vectibix on 3 December 2007.
For more information about treatment with Vectibix, read the package leaflet (also part of the EPAR) or contact your doctor or pharmacist.
Source: European Medicines Agency
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