PD-1 Immune Checkpoint Inhibitor Pregnancy: Contraindicated in pregnancy — can cause immune-mediated fetal harm

Pembrolizumab

Brand names: Keytruda

Adult dose

Dose: 200 mg every 3 weeks or 400 mg every 6 weeks

Route: Intravenous infusion (over 30 minutes)

Frequency: Every 3 or 6 weeks

Max: 200 mg per 3-week cycle (or 400 mg per 6-week cycle)

Urothelial carcinoma: first-line in cisplatin-ineligible patients with PD-L1 positive tumours, or second-line after platinum-based chemotherapy. Also approved in BCG-unresponsive high-risk NMIBC with CIS

Paediatric dose

Dose: Seek specialist opinion N/A/kg

Route: IV

Frequency: Seek specialist opinion

Max: Seek specialist opinion

Seek specialist opinion

Dose adjustments

Renal

No dose adjustment required

Hepatic

No dose adjustment for mild impairment; withhold for immune-mediated hepatitis

Paediatric weight-based calculator

Patient weight (kg)

Seek specialist opinion

Clinical pearls

PD-L1 testing is required before use in first-line cisplatin-ineligible urothelial carcinoma (CPS score 10 or above for pembrolizumab per NICE TA644)
Immune-related adverse events (irAEs) can affect any organ — most commonly endocrine, GI, hepatic, and pulmonary; can occur weeks to months after last dose
Endocrine irAEs (thyroid, adrenal, pituitary) often require permanent hormone replacement even after discontinuing pembrolizumab
Educate patients with steroid card to carry — for emergency management of adrenal insufficiency if immune-mediated adrenalitis occurs
KEYNOTE-052 and KEYNOTE-045: established pembrolizumab in first- and second-line urothelial carcinoma respectively

Contraindications

Active autoimmune disease requiring systemic immunosuppression
History of severe immune-related adverse events on prior checkpoint inhibitor

Side effects

Immune-related adverse events (irAEs): pneumonitis, colitis, hepatitis, endocrinopathies (thyroiditis, adrenal insufficiency, type 1 diabetes)
Fatigue
Rash
Pruritus
Infusion reactions
Musculoskeletal pain

Interactions

Systemic corticosteroids (reduce efficacy if given prophylactically; needed for toxicity management)
Other immunosuppressants (reduce efficacy)

Monitoring

TFTs and morning cortisol (endocrine monitoring)
LFTs
Renal function
Blood glucose
Chest imaging if respiratory symptoms
Skin and GI symptoms at each visit

Reference: BNFc; BNF 90; NICE TA644 (Pembrolizumab for urothelial carcinoma); KEYNOTE-052; KEYNOTE-045; EAU Bladder Cancer Guidelines 2024. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways