Pembrolizumab (Rx)

Action and Spectrum

Pembrolizumab binds to PD-1 receptor and interacts with the ligands PD-L1 and PD-L2 on the antigen presenting cells and tumor cells. The interaction of PD-1 and PD-L1 is an immune checkpoint and inhibits the immune response and prevent the T cells to attack the cancer cells. Pembrolizumab inhibits PD-1 and allows the T cells to identify and attack the cancer cells more accurately. 

Drug Interaction

Adverse Reaction

Frequency defined   

>10%  

Cardiac arrhythmia  

peripheral edema  

Pruritus  

skin rash  

vitiligo  

Decreased serum bicarbonate  

Hypercalcemia  

Hypercholesterolemia  

Hyperglycemia  

Hyperkalemia  

Hyperthyroidism  

Hypertriglyceridemia  

Abdominal pain  

Constipation  

decreased appetite  

diarrhea   

Hyperbilirubinemia  

increased serum alkaline phosphatase  

Infection  

1-10%  

Acute myocardial infarction  

cardiac tamponade  

ischemic heart disease  

myocarditis  

ericardial effusion  

herpes zoster infection  

Black Box Warning

Pembrolizumab does not have any black box warning because of the mechanism of improving the immune responses.  

Contraindication / Caution

There is not any contraindications which is reported by FDA. It is necessary to take cautions because of the risk of severe immune mediated adverse reactions. It occurs because pembrolizumab activate the immune system and can kill the healthy cells along with the cancer cells. 

Pregnancy / Lactation

Pregnancy warnings:     

• US FDA pregnancy category: Not assigned. 

Breastfeeding warnings:  

• The release of the drug into the human breastmilk is unknown   

Pregnancy Categories:       

Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first trimester or the later trimester.       

Category B: No evidence shown of risk to the fetus found in animal reproduction studies, and there are not enough studies on pregnant women       

Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for a result in humans must take care of potential risks in pregnant women       

Category D: There is adequate data available with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits       

Category X: Drugs listed in this category outweigh risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.       

Category N: There is no data available for the drug under this category

Pharmacology

Pharmacodynamics: 

Pembrolizumab is a monoclonal antibody (mAb) which binds to the PD-1 receptors on the T cells. It blocks the interaction between the PD-1 and PD-L1 and PD-L2 and over produced in the tumor cells. Pembrolizumab promotes the activations and proliferation of T cells and activate the immune response against the tumor cells.  

Pharmacokinetics: 

Absorption: 

Pembrolizumab is administered by IV infusion. It goes to the peak plasma levels at the end of infusion. 

Distribution: 

The volume of distribution is about 7.7 L. It may differ depends on the presence of the tumor or immune system mediated disease.  

Metabolism: 

Pembrolizumab is mainly metabolized by the proteolytic enzymes in the body. It does not go for the hepatic metabolism. 

Elimination: 

The ½ life of pembrolizumab is about 26 days and needs few administration. The elimination is mainly by the reticuloendothelial system. The normal rate of clearance is about 0.2 L per day.    

Adminstartion

Pembrolizumab is mainly administered for every 3 weeks in the dosage of 200 mg or for every 6 weeks in the dosage of 400 mg depending on the particular indications and factors of the patient.

Patient Information Leaflet

Generic Name: pembrolizumab (Rx) 

Pronounced: pem-bro-li-zu-mab 

Why do we use pembrolizumab? 

pembrolizumab is an anticancer drug belongs to sub-class monoclonal Antibody used to treat non-small cell lung cancer (NSCLC), head and neck cancer, melanoma and cervical cancer.