Erbitux is part of medicines called monoclonal antibodies, which are substances similar to antibodies produced in the human body itself, with specific binding to some substances, such as certain proteins .
Thus, it works by blocking the growth of tumor cells and preserving healthy tissues.
In the case of the active substance cetuximab, it binds to an epidermal growth factor (EGFR), which is an antigen present in some tumor cells.
Because it is a target medication, acting specifically on sick cells, cetuximab generally causes fewer adverse effects, even though they may occur.
What is Erbitux for? According to the package leaflet, Erbitux is indicated in two situations, being the treatment of patients with mutated RAS metastatic colorectal cancer without expression of the epidermal growth factor receptor (EGFR), and also treatment of patients with squamous cell carcinoma of head and neck.
Learn more about each one and how the medicine is indicated:
RAS metastatic colorectal cancer, not mutated and with epidermal growth factor receptor (EGFR) expression Colorectal cancer is also called bowel cancer. According to data from INCA, it is the third most common cancer among men and the second among women.
In advanced stages, the disease (or the primary tumor) spreads to other parts of the body, that is, it undergoes metastasis. Generally, the liver or lungs are the regions most affected by metastases from this type of cancer.
When it occurs, treatment becomes considerably more difficult and there is a reduction in the survival rate of patients, with approximately 12% of people living longer than 5 years after diagnosis.
RAS is a marker for a group of genes. It is more or less like a specificity that characterizes them. This marker is found in many types of cancer, including colorectal cancer.
In cases of metastatic colorectal cancer, it is estimated that half of the diagnosed people have tumors with an unmutated type of RAS (wild) and the other half have mutant tumors.
This RAS gene has an important triggering mechanism in the proliferation of colorectal disease. In the wild (or not mutated), the attachment of a growth factor to the membrane receptor triggers an enzymatic process that activates cancer-related genes.
With a biomarker test, it is possible to detect the type and status of these genes, helping to choose accurate treatment methods.
This is because the choice of therapies to inhibit the epidermal growth factor receptor (EGFR) has shown good results to treat cases of metastatic colorectal cancer with tumors that have not undergone RAS mutations.
According to the package insert, in this case, Erbitux should be used:
In combination with irinotecan-based chemotherapy or with oxaliplatin plus 5-fluorouracil and folinic acid in continuous infusion; As a single agent in patients who do not respond well to therapy based on oxaliplatin and irinotecan, and who are intolerant to irinotecan. Squamous cell carcinoma of the head and neck Squamous cell carcinoma of the head and neck (HNSCC) represents a high prevalence among cancers of the head and neck – formed by a large group of diseases that affect these regions of the body.
HNSCC originates in the scaly coatings on the surface of the upper mucous membranes, which may include the oral cavity, pharynx, larynx and nasal sinus tract. In advanced stages, it is also easy to metastasize, due to the ease of migrating to the cervical lymph node and reaching the bloodstream.
Due to the rapid onset of the organism, the disease is related to low survival rates.
According to the Brazilian Society of Head and Neck Surgery, the disease affects about 650 thousand people annually in the world.
According to the package insert, Erbitux is indicated as follows for the treatment of squamous cell carcinoma of the head and neck:
In combination with radiotherapy for locally advanced disease in patients who, according to medical criteria, cannot be treated with the combination of chemotherapy plus radiotherapy; In combination with platinum-based chemotherapy for recurrent and / or metastatic disease. What is the active substance in Erbitux and how does it act? The active ingredient in Erbitux is Cetuximab, a monoclonal antibody, with an affinity for epidermal growth factor (EGFR). That is, a substance produced in the laboratory, similar to the human antibody, which specifically acts as a union with the EGFR.
This binding then inhibits the activation of the receptor, causing the transmission of signals that promote or continue the proliferation of cancer to be interrupted.
According to the Brazilian Society of Head and Neck Surgery, it is still possible for the drug to act directly on the action of malignant cells. This is because it is believed that these tumor cells have the capacity to regenerate themselves, repairing the damage caused by chemotherapy and radiotherapy.
Cetuximab, then, can act to prevent recovery from this damage. In addition, there is inhibition of blood vessels due to the recovery of damage and also the action of the drug, which prevents its growth.
What are the side effects? As with other medications, the use of Erbitux can have adverse effects. They will not necessarily occur and, when they do, they can vary in frequency and intensity according to each patient.
According to the package leaflet, the most common adverse effects are related to the infusion itself, which can very commonly cause fever , chills, dizziness and difficulty breathing.
Commonly, they are also hives, chest pains, fainting and severe difficulty in breathing with rapid development. Skin-related reactions tend to be quite common as well.
The package insert indicates that at least 80 out of every 100 patients can manifest a condition, with the majority being present during the first 3 weeks of treatment.
Very common are skin changes such as acne , itching, dry skin, flaking, increased amount of hair and changes in the nails (for example, inflammation of the tissues below them).
Other reactions that may be common or very common are:
Inflammation of the lining of the intestine, mouth and nose (which can cause nosebleeds); Decreased concentration of magnesium in the blood; Increased amount of some liver enzymes in the blood; Headache; Tiredness; Irritation and redness in the eyes; Diarrhea; Feeling sick; Vomiting; Loss of appetite; Reduction of blood calcium levels. Does the package insert have contraindications? Yes. According to the package insert, there are two cases contraindicated to the use of the medication Erbitux. The first is hypersensitivity ( allergy ) to the active substance cetuximab and the other is that the diagnosis indicates a mutated RAS tumor or if the RAS status of the tumor is unknown.
Therefore, it is important to perform a RAS test, which will help the medical team to identify whether the condition is a wild (unaltered) or mutated RAS. That’s because some people have cells that undergo genetic modification, generating mutated RAS.
Thus, even if there is a blockage of EGF receptors, there is still a signal to the cells to proceed with the proliferation of tumor cells and the drug has no effect.
The RAS test occurs by means of a biopsy, in which fragments of the tumor tissue are analyzed.
Merck Laboratory Program for Erbitux The Merck company has the Conviva Bem Program, which provides assistance to patients undergoing cancer treatment. By registering on the site, people can receive newsletters, news about therapies and medications, as well as tips on well-being and ways to better deal with the stages of the disease.
The main idea of the program is to provide emotional and educational support to patients and families, bringing more comfort and tips on how to maintain an adequate routine, clarifying doubts and publicizing actions aimed especially at people undergoing treatment.
To do this, simply register on the program website or by phone.
Price and where to buy Erbitux On average, the values of Erbitux 5mg / mL, box with 1 vial with 20mL of solution for intravenous use are between R $ 750 and R $ 1030 *.
The presentation of Erbitux 5mg / mL, box with 1 vial with 100mL of solution for intravenous use can vary between R $ 3700 to R $ 5300, approximately *.
* Prices consulted in November 2019. Prices may change.
Is Erbitux approved by ANVISA? Yes. Erbitux is approved by ANVISA, having registered and, therefore, allowed for sale since 2006, in the Antineoplastic category.
Is Cetuximab offered by SUS? No. Cetuximab is not supplied by SUS directly. However, people with indication of use can file a lawsuit, requesting the cost of treatment.
Likewise, people who have health plans can file a lawsuit against the plan, which, if unsuccessful, should pay for treatment.
In both cases, it is necessary to initially make an administrative request – either in SUS or in the administration of the private health plan -, requiring medication.
If there is a denial, the person must resort to legal channels, presenting the Medical Report (LME), medical prescription, justification and 3 different pharmacy budgets.
To facilitate this process, it is possible to count on the advice of quotation on high-cost drugs , Consulta Remédios. By filling out the form, in a short time, the person receives the 3 necessary budgets.
It is indicated that all doubts about how to start the process and what the correct procedures should be clarified with the doctor who prescribed the medication, followed by the assistance of a lawyer.
Cetuximab is among the active substances called target therapy. Produced to act with high specificity in diseased cells, it is indicated for use in some cases of metastatic colorectal cancer and also squamous cell carcinoma of the head and neck.
Approved by ANVISA, Erbitux, from the Merck laboratory, is a drug option that has shown good results in these indicated charts.
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