Colorectal cancer is a life-threatening disease that affects millions of people around the world. It is the third most diagnosed cancer.
Fortunately, advances in medical science have led to the development of new treatments that can fight this deadly disease. One such treatment is Vectibix (panitumumab).
By targeting a protein found on the surface of cancer cells, Vectibix slows the growth and spread of cancer cells, providing hope to patients and their families. However, like all cancer treatments, Vectibix has some side effects that must be closely monitored.
In this article, we will take a closer look at Vectibix, its uses, how it works, its potential benefits, and risks.
What Is Vectibix?
Vectibix is a medication used to treat metastatic colorectal cancer (mCRC), particularly wild-type RAS mCRC.
Clinical trials have been conducted to assess the safety and effectiveness of Vectibix for cancer treatment. Notable trials include the PRIME trial, which demonstrated that Vectibix combined with chemotherapy had a longer progression-free survival in metastatic colorectal cancer patients.
The ASPECCT trial compared Vectibix to another EGFR-blocking medication and showed that it worked just as well compared to the EGFR treatment already on the market.
From these analyses, it was concluded that the benefits of Vectibix outweigh its side effects. Due to its efficacy, the U.S. FDA approved the drug in 2006.
Although these trials suggest Vectibix can be an effective treatment option, it is important to discuss the benefits and risks with your doctor before starting treatment.
What Is Vectibix Used For?
Primarily, Vectibix is used as a first-time treatment to manage wild-type RAS metastatic colorectal cancer. It is usually combined with another chemotherapy regimen known as FOLFOX (fluorouracil, leucovorin, and oxaliplatin) to address this illness.
Wild-type RAS refers to cancer that doesn’t have mutations in the NRAS and KRAS genes. It is not advisable to undergo this therapy if you have RAS-mutant tumors or if your RAS status is unknown. This is because the mutant tumors may stir up serious side effects without you benefiting from the medication.
Vectibix may also be used alone, depending on the progression of the disease. This is usually after a patient has had oxaliplatin-, irinotecan-, and fluoropyrimidine-containing chemotherapies.
Ultimately, the goal of using Vectibix is to lengthen patient survival rates and slow down cancer cell growth.
How Does Vectibix Work?
Vectibix belongs to a class of drugs called monoclonal antibodies. Monoclonal antibodies are artificially created proteins that act like human antibodies to target and destroy a specific molecule or protein in the body. Through this mechanism, Vectibix inhibits the activity of epidermal growth factor receptor (EGFR), a protein found on the surface of certain cancer cells.
EGFR is responsible for regulating cell growth and survival, including cancer cells. And by targeting it, Vectibix blocks its activity. It prevents signals from being transmitted inside the cell, thus interrupting the cell growth and division process, resulting in cell death.
Side Effects
Vectibix can lead to several side effects, some of which can be severe. The following are some common side effects that patients may experience while taking this medication:
- Skin rash and itching: This is the most common side effect. The rash can range from mild to severe and may require treatment with topical or oral medications. Symptoms may include redness, acne-like rash, skin peeling, openings in the skin, and nail infections.
- Fatigue
- Nausea and vomiting
- Diarrhea
- Abdominal pain
- Headache
- Constipation
- Eye disorders: Vectibix can cause eye disorders, such as corneal erosion or ulceration.
This is in no way an exhaustive list of the side effects patients may experience. Hence, you should report any reactions you notice to your healthcare provider, no matter how subtle. Your doctor can also provide guidance on managing side effects.
In addition to these common side effects, Vectibix can also cause more serious side effects, such as:
- Pulmonary fibrosis: Vectibix can cause scarring of the lungs, which can be life-threatening.
- Severe skin reactions: This medication can cause severe skin reactions, such as Stevens-Johnson syndrome or toxic epidermal necrolysis, which can be life-threatening.
Dosage
The dosage of Vectibix can vary depending on your weight and response to treatment. It is important to follow the dosage instructions provided by your healthcare provider.
For the treatment of metastatic colorectal cancer, the recommended dosage of Vectibix is 6 mg/kg given as an intravenous infusion every 2 weeks. The first infusion should be given over 60 minutes, and subsequent infusions can be given over 30-60 minutes if the patient tolerates the medication well. Doctors may make adjustments if patients react negatively.
It is important that you receive this medication from a healthcare provider who has been trained in its administration. The medication requires specialized preparation and administration. In addition, regular monitoring may be necessary to evaluate the effectiveness of the medication and monitor for potential side effects.
Precautions
There are several precautions that you should take into consideration when and after using Vectibix:
- Hypersensitivity infusion reactions: Some people may experience allergic reactions such as fever, chills, and rash during or after infusing Vectibix. These patients should be monitored for signs of allergic reactions.
- Skin toxicity: Vectibix may cause severe acne-like rash, dry skin, and nail changes. Patients should use sunscreen and avoid excessive sun exposure, as well as keep their skin clean and moisturized. Topical or oral medications may be used to manage skin toxicity.
- Pulmonary fibrosis: The medication has been linked to interstitial lung disease and pulmonary fibrosis, which can be fatal. Patients should be monitored for signs of respiratory distress.
- Electrolyte imbalances: Vectibix may cause imbalances in electrolytes such as magnesium, calcium, and potassium, which can lead to serious complications. Blood tests may be necessary to monitor electrolyte levels during treatment.
- Eye disorders: Vectibix may cause eye disorders such as corneal erosion or ulceration. Patients should be monitored for symptoms such as eye pain, redness, or sensitivity to light.
- Pregnancy and breastfeeding: Pregnant or breastfeeding women should not take this medication as it may cause fetal harm. It is not known if the medication is excreted in breast milk. Birth control should be used during treatment and for at least 2 months following the last dose of Vectibix.
- Interactions with other medications: Vectibix may interact with other medications, including some chemotherapy drugs and immunosuppressive medications. You should inform your doctor of all medications you are taking including over-the-counter (OTC) medications and herbal supplements.
Overall, it’s advisable that you follow all instructions provided by your healthcare provider to minimize the risk of complications.
Cost
Vectibix’s cost varies based on dosage, frequency, and healthcare coverage. Prices differ across countries due to local policies and systems. Discuss the cost with your healthcare provider or pharmacist and explore available resources to make it affordable.