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Lung Oncology Pregnancy: Contraindicated — PD-1/PD-L1 blockade can cause immune-mediated fetal harm; effective contraception required during and for 4 months after last dose

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 dose (Q3W) or 400 mg per dose (Q6W)
PD-1 immune checkpoint inhibitor. First-line NSCLC (TPS >=50%, no EGFR/ALK mutation). With chemotherapy for TPS <50%. Continue until disease progression, unacceptable toxicity, or 2 years.

Paediatric dose

Dose: 2 mg/kg
Route: IV infusion
Frequency: Every 3 weeks
Max: 200 mg per dose
Licensed for certain paediatric indications; seek specialist oncology opinion for respiratory tumours

Dose adjustments

Renal

No dose adjustment required

Hepatic

No dose adjustment for mild-moderate hepatic impairment; limited data in severe impairment

Paediatric weight-based calculator

Licensed for certain paediatric indications; seek specialist oncology opinion for respiratory tumours

Clinical pearls

  • KEYNOTE-024 (Reck et al. NEJM 2016): pembrolizumab vs platinum-doublet in TPS >=50% NSCLC — mPFS 10.3 vs 6.0 months; OS 30 vs 14.2 months. Landmark trial.
  • KEYNOTE-189: pembrolizumab + pemetrexed/platinum for non-squamous NSCLC regardless of TPS — PFS and OS benefit. Standard of care for TPS <50%.
  • PD-L1 TPS scoring essential: TPS >=50% = monotherapy; TPS 1-49% or <1% = combination with chemotherapy
  • irAE management: grade 2 pneumonitis — hold, prednisolone 1 mg/kg; grade 3-4 — discontinue permanently, high-dose steroids
  • MSI-H/dMMR or TMB-high tumours: pembrolizumab approved tumour-agnostically — relevant for NSCLC with these biomarkers

Contraindications

  • Pregnancy
  • Active autoimmune disease requiring systemic treatment
  • Hypersensitivity

Side effects

  • Immune-mediated pneumonitis (3-4%)
  • Immune-mediated colitis
  • Immune-mediated hepatitis
  • Immune-mediated endocrinopathies (hypothyroidism, hypophysitis, adrenal insufficiency)
  • Immune-mediated nephritis
  • Infusion reactions
  • Fatigue
  • Rash

Interactions

  • Systemic corticosteroids — may reduce efficacy if used before cycle 1; use for irAE management
  • Other immunosuppressants — avoid before starting

Monitoring

  • PD-L1 TPS score
  • LFTs
  • TFTs, cortisol, ACTH
  • Creatinine
  • Chest imaging
  • Blood glucose

Reference: BNFc; BNF 90; KEYNOTE-024 (Reck et al. NEJM 2016); KEYNOTE-189 (Gandhi et al. NEJM 2018); NICE TA447; SPC Keytruda. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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