Vectibix 100 Injection

Description of Vectibix 100 (Panitumumab 100 mg) injection

Vectibix 100 injection consists of Panitumumab which is a completely human monoclonal antibody that is used in the targeted therapy of malignancies. Panitumumab is particularly a selective binding agent of epidermal growth factor receptor (EGFR) transmembrane protein on the surface of particular tumour cells. EGFR plays a central role in cell proliferation, survival and differentiation. In a variety of carcinomas, unregulated tumour growth is boosted by aberrant expression of this receptor. Through its interactions with EGFR, Panitumumab disturbs the association between the receptor and its endogenous ligands, and thus disturbs the downstream signalling cascades that support tumour cell proliferation and survival, and, as a result, suppresses the progression of the disease.

Indications of Vectibix 100 (Panitumumab 100 mg) injection

Panitumumab is mostly used in the treatment of  Metastatic colorectal carcinoma and  neoplasmas with wild type KRAS gene and Neoplasms expressing EGFR. The administration is mostly done as monotherapy or with chemotherapy programmes to patients whose malignancy has advanced despite the administration.

Mechanism of Action of Vectibix 100 (Panitumumab 100 mg) injection

Panitumumab is a monoclonal antibody which targets the extracellular domain of epidermal growth factor receptor (EGFR). The EGFR conjugation with a ligand brings about a conformational transition in the protein, which initiates intracellular downstream signalling cascades to promote tumourigenesis, cellular survival and metastatic progression. Panitumumab inhibits binding of ligands thus blocking receptors. This leads to the inhibition of downstream signalling that causes oncogenic proliferation. Moreover, the EGFR blockade can improve the tumour cell responsiveness to the adjunct anticancer treatment.

How to Consume Vectibix 100 (Panitumumab 100 mg) injection

Panitumumab is intravenously administered and is under the supervision of medical personnel in an oncology environment. Infusion is usually conducted every two weeks according to the schedule that has been suggested by the oncologist. Dosage is determined on the body weight and clinical status of a patient. The infusion process is carried out gradually to alleviate adverse reactions to infusion.

Side Effects of Vectibix 100 (Panitumumab 100 mg) injection

1. Common side effects

• Acne-like skin rash
• Fatigue
• Diarrhea
• Nausea
• Dry skin or itching

2. Serious side effects

• Severe skin infections
• Electrolyte imbalance
• Severe diarrhea leading to dehydration
• Infusion reactions

3. Rare side effects

• Interstitial lung disease
• Severe allergic reactions
• Cardiac complications

Safety Advice for Vectibix 100 (Panitumumab 100 mg) injection

Clients on Panitumumab are supposed to have a routine cheque-up, including a periodical test of the electrolytes, haematological variables, and skin reactions.

Breastfeeding: Breastfeeding must be avoided in the course of therapy since the monoclonal antibodies may be transferred into the breast milk and cause the babies to be influenced.

Pregnancy:. The use of panitumumab in pregnancy is contraindicated since exposure of the foetus to EGFR pathway inhibition would interfere with normal developmental events.

 Alcohol: Alcohol intake is to be kept down to a minimum since it can enhance fatigue and dehydration.

Liver: In the case of panitumumab, in combination with chemotherapy, both hepatic monitoring during treatment is recommended.  .

Lungs: Patients need to report persistent cough or dyspnea immediately.

Kidney: The renal functioning is to be monitored during the therapeutic intervention along with the electrolyte concentration examination.

Driving: People who are dizzy or fatigued are discouraged to drive or take up work that involves heavy machinery.

Interaction of Vectibix 100 (Panitumumab 100 mg) injection

• Drug–Drug Interaction

Fluorouracil × Panitumumab
Fluorouracil should be used concomitantly with panitumumab, which can enhance gastrointestinal toxicity and excessive bone marrow.

Oxaliplatin × Panitumumab

Combination therapy has the potential of increasing the risk of severe neutropenia and infections..

Irinotecan × Panitumumab
Such duo could increase the risk of diarrhoea and gastrointestinal irritation.

Paclitaxel × Panitumumab   

Simultaneous administration can increase dermatological toxicity and infusion reactions.

Other EGFR inhibitors × Panitumumab
The combination of several EGFR -targeting medications could potentially increase the adverse effects on the skin.

• Drug–Food Interaction

Panitumumab is intravenously administered hence food intake does not make significant impact on its absorption. Nonetheless, proper hydration is advisable and balanced feeding during treatment.

• Drug–Disease Interaction of Vectibix 100 (Panitumumab 100 mg) injection

Skin Disorders

Panitumumab is usually known to cause dermatological reactions because of the expression of EGFR receptors in skin cells. The pre-existing skin cases can lead to aggravation of the symptoms in patients.

Electrolyte Imbalance 

The medication can cause hypomagnesemia and other electrolyte imbalances; patients having underlying metabolic diseases should be carefully monitored.

Pulmonary Disease 

The possibility of interstitial lung disease is increased among the patients who already have pulmonary conditions.

Gastrointestinal Disorders 

Several severe diarrhoea can be experienced especially when using panitumumab with chemotherapy.

Contraindication of Vectibix 100 (Panitumumab 100 mg) injection

Panitumumab should not be used in patients who experience hypersensitivity to the drug or to its excipients. In addition, its use is considered unsuitable among patients with tumours with the KRAS mutation since the level of therapeutic effectiveness is significantly decreased in this patient group.

Dosage of Vectibix 100 (Panitumumab 100 mg) injection

The dosage depends on the body weight and the treatment programme. It is normally given once every two weeks as a venous intrusion under medical care.

Storage of Vectibix 100 (Panitumumab 100 mg) injection

The drug is to be kept in refrigerator, not exposed to too much heat and light. The vial should be stored in the original packaging till preparation and not accessible to children.

Missed Dose of Vectibix 100 (Panitumumab 100 mg) injection

Due to the fact that the drug is administered in a healthcare facility, the instances of missed doses are not common. In case of an infusion delay, the oncologist will decide how to make an adjustment of the treatment schedule.

Other General Information of Vectibix 100 (Panitumumab 100 mg) injection

During therapy, patients should have good skin care as dermatological reactions are frequent. Skin irritation can be reduced by using moisturisers and not spending too much time in the sun. Medical follow-up should be regular to control the response to treatment and prevent some side effects.

FAQs of Vectibix 100 (Panitumumab 100 mg) injection

1. What is the reason why so many patients experience skin reactions when using Panitumumab?

Normal cutaneous cells have EGFR receptors. Panitumumab inhibits EGFR activity hence disrupting normal skin cell growth and repair leading to acne-like rashes or xerosis.

2. What is the rationale in having genetic testing prior to administration of Panitumumab?

Panitumumab has been shown to be beneficial in tumours that have a wild-type KRAS gene. In case of mutation of the gene KRAS, the drug is not likely to have therapeutic effect; therefore, genetic testing assists in determining the suitability of the treatment.

3. What are the reasons of monitoring electrolyte levels in the course of Panitumumab treatment?

The drug can make one hypomagnesaemic and other electrolyte imbalanced. These changes can be detected early through serial blood tests and thus supplementation can be done accordingly.

4. Is Panitumumab infusible with allergic reactions?

Even though extreme reactions are not frequent as with a few other monoclonal antibodies, the infusion of reactions like fever, chills or respiratory distress can happen. Close observation of patients is done by the healthcare staff during the infusion.

5. What is the normal duration of Panitumumab treatment?

The length of treatment is determined by the reaction of the patient and health condition. The process may continue in a number of cycles as long as the drug is effective and the side effects are manageable.

Fact Box of Vectibix 100 (Panitumumab 100 mg) injection

References

• FDA Prescribing Information – Vectibix (Panitumumab)
  https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/125147s228lbl.pdf
• National Cancer Institute – Panitumumab
  https://www.cancer.gov/about-cancer/treatment/drugs/panitumumab
• DrugBank – Panitumumab
  https://go.drugbank.com/drugs/DB01269
• European Medicines Agency – Vectibix Product Information
  https://www.ema.europa.eu/en/documents/product-information/vectibix-epar-product-information_en.pdf