INTRODUCTION
Millions of people suffer from cancer and lose their lives every year. We startle when we hear about cancer. The fear of losing our loved ones and chemotherapy that shakes the whole body to its core takes root in our hearts and minds.
Let’s talk about the most sold medicine in the world: Keytruda (pembrolizumab) is manufactured by Merck & Co., holding the top position and selling over 29 billion USD.
Cancer immunotherapy: Currently researchers pay more attention to boosting the body’s immune system to recognize and fight tumor-specific cells and show long-sustained effects compared to chemotherapy, which is short-term and kills fast-growing normal cells too.
Mechanism of action
Keytruda is a humanized IgG4-kappa monoclonal antibody. Targeting program death receptors (PD-1) present on the T-cells allows T-lymphocytes to detect and destroy cancer cells. It blocks PD-1 receptor ligands such as PD-L1 and PD-L2, which are expressed in tumors, conveying a signal to the T cells, resulting in the restoration and generation of an immune response cascade.
What makes it unique from other existing anticancer drugs?
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Diversity: It targets approximately 20 types of cancer, making it a first-line drug of choice.
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Long-sustained effects: owing to a 22-day half-life, it enables it to continue to fight malignant cells for extended periods.
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Less recurrent dose: instead of daily or weekly IV administration, it only needs to be administered after 2-3 weeks owing to prolonged stays in the body.
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Immunomodulatory: maintain the immune system to cope with melanoma cells.
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Bioavailability: Infused intravenously, it reaches 100% in systemic circulation immediately and completely.
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Prolonged median progression-free survival (PFS): more than 10 months compared to chemotherapy (6 months).
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Overall survival (OS) rate: 34% of patients have shown 10 years of OS compared to 23.6% of older therapies (ipilimumab).
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Combined therapies: Keytruda alone shows higher efficacy than chemotherapy.
Uses
non-small cell lung cancer, head and neck cancer, cervical cancer, Hodgkin’s lymphoma, breast cancer, skin cancer, etc.
Immunointerceded implications
Colitis
Pneumonitis
Hepatitis
Endocrinopathies
Thyroiditis, etc.
Modes of Application 
Administered intravenously (IV) and subcutaneously (SC).
Dosage and Recurrence
3 weeks - frequently 200 mg or 2 mg/kg
6 weeks - often 400 mg
Side effects : Nausea, vomiting, pain, fatigue, rash, itching, diarrhea, anorexia, etc.
Conclusion
Keytruda’s versatility, safety, efficacy profile, and systematic targeting approach set it distinct from other market-available drugs, making it physicians’ first choice of drug in cancer treatment. The study needs to be continued, and in-depth studies are required in immunocompromised patients.
What do you know about cancer immunotherapy and other particular ongoing research on cancer?
MBH/PS