For doctors

What is it?

Vectibix is a concentrate that is made up into a solution for infusion (drip into a vein). It contains the active substance panitumumab.

What is it used for?

Vectibix is used to treat metastatic carcinoma 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 on its own in patients whose tumour cells have a protein on their surface called the epidermal growth factor receptor (EGFR) and which contain a non-mutated ‘ KRAS’. KRAS is a gene that, when mutated in tumour cells, stimulates tumour growth. Vectibix is used 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 it used?

Treatment with Vectibix should be supervised by a doctor who has experience in the use of anticancer therapy. It should only be started once detection of non-mutated KRAS has been performed by an experienced laboratory using a reliable 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.

How does it 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 KRAS. 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 it been studied?

Vectibix has been studied in one main study involving 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 how long the patients lived without their disease getting worse. The results of the study were analysed separately in 243 patients whose tumours contained KRAS that had not mutated and in 184 patients in whom the KRAS gene contained a mutation.

What benefits has it shown during the studies?

The patients with non-mutated 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.

What is the risk associated?

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 1 patient in 10) are acneiform dermatitis (skin inflammation resembling acne), rash, exfoliative rash (flaky rash), erythema (reddening of the skin), skin exfoliation (skin flaking), pruritus (itching), dry skin, skin fissures (cracks in the skin), diarrhoea, nausea (feeling sick), vomiting, abdominal pain (stomach ache), constipation, fatigue (tiredness), pyrexia (fever), paronychia (nail bed infection), dyspnoea (difficulty breathing), cough, nail disorders and hypomagnesaemia (low blood magnesium levels). 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).

Why has it 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 non-mutated KRAS. Every year, the European Medicines Agency will review any new information that may become available and this summary will be updated as necessary.

How has it been studied?

The company that makes Vectibix will supply the results of additional studies looking at the safety and effectiveness of the medicine in patients with colorectal cancer with and without mutated KRAS. These include a study looking at the use of Vectibix in combination with other medicines in patients whose disease has been treated before, as well as 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 KRAS mutations.

Further information

The European Commission granted a conditional marketing authorisation valid throughout the European Union for Vectibix to Amgen Europe B.V. on 3 December 2007. The conditional marketing authorisation has been renewed every year since then. europa.eu/Find medicine/Human medicines/European Public Assessment Reports. For more information about treatment with Vectibix, read the package leaflet (also part of the EPAR) or contact your doctor or pharmacist.

This summary was last updated in 10-2010.

Name

Vectibix 20 mg/ml concentrate for solution for infusion

Composition

Each ml of concentrate contains 20 mg panitumumab.

Each vial contains either 100 mg of panitumumab in 5 ml, 200 mg in 10 ml, or 400 mg in 20 ml.

When prepared according to the instructions given in section 6.6, the final panitumumab concentration should not exceed 10 mg/ml.

Panitumumab is a human monoclonal IgG2 antibody produced in a mammalian cell line (CHO) by recombinant DNA technology.

Excipient:
Each ml of concentrate contains 0.150 mmol sodium, which is 3.45 mg sodium.
For a full list of excipients, see section 6.1.

Pharmaceutical Form

Concentrate for solution for infusion.

Colourless solution that may contain, translucent to white, visible amorphous, proteinaceous panitumumab particles.