pembrolizumab: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
pembrolizumab: clinical details
Prescribing considerations
- Treatment initiation and supervision require clinicians experienced in cancer care.
- Confirm PD-L1 or MSI/MMR status with a validated test when required by the licensed indication.
- Review autoimmune disease, previous pneumonitis or severe checkpoint-inhibitor toxicity, active infection, viral infection, organ impairment and transplant history.
- Educate patients about delayed and multisystem immune-related toxicity and issue the patient alert card.
- The subcutaneous formulation is authorised for adults; selected paediatric uses require the intravenous formulation.
Contraindications and cautions
- Hypersensitivity to pembrolizumab or any formulation excipient.
- Pre-existing autoimmune disease, transplant history and previous severe immune-mediated toxicity are not absolute product contraindications but require careful individual benefit-risk assessment.
Monitoring
- Assess new symptoms before each administration and after treatment ends; immune-related effects can involve multiple organs simultaneously.
- Monitor liver, renal and thyroid function at baseline and periodically; assess glucose and pituitary or adrenal function when clinically indicated.
- Investigate suspected pneumonitis, colitis, hepatitis, nephritis, endocrinopathy, severe skin toxicity, myocarditis, neurological toxicity or administration reactions promptly, excluding alternative causes.
- Record the product name and batch number for biological traceability.
Clinical pharmacology
Pembrolizumab is a humanised IgG4 monoclonal antibody that blocks PD-1 binding to PD-L1 and PD-L2, increasing T-cell activity. It is cleared by protein catabolism rather than conventional hepatic drug-metabolising pathways.
Formulation and product differences
- The intravenous product is a concentrate requiring dilution before infusion.
- The subcutaneous product is a ready-to-use solution containing recombinant berahyaluronidase alfa to facilitate administration into subcutaneous tissue.
- Intravenous and subcutaneous products have different routes, preparation requirements and authorised paediatric populations; label and formulation checks are essential to prevent medication error.
- Patients may switch route at a planned treatment visit when clinically appropriate.
pembrolizumab preparations and strengths
Solution for infusion
Route: Intravenous
Strengths: 25 mg/mL
Injection
Route: Parenteral
Strengths: 395 mg, 790 mg
pembrolizumab interactions
Formal pharmacokinetic interaction studies are limited. Pembrolizumab is broken down like other antibodies, so conventional metabolism-based interactions are not expected.
Systemic corticosteroids or other immunosuppressants
Avoid routine immunosuppression before starting where possible because it may reduce pembrolizumab's immune activity; these treatments may still be required to manage immune-related toxicity or support combination therapy.
Other anticancer treatments
Combination treatment can substantially change adverse effects and monitoring requirements, so the accompanying product information must also be reviewed.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.