Pembrolizumab and nivolumab treat cancer by blocking which checkpoint inhibitory pathway?

• A CTLA-4 / B7-1/B7-2 interaction, blocking T-cell anergy induction
• B LAG-3 / MHC Class II interaction, preventing regulatory T-cell exhaustion
• C PD-1 / PD-L1 interaction, restoring T-cell cytotoxic function in the tumour microenvironment ✓
• D TIM-3 / Galectin-9 interaction, reducing tumour-infiltrating T-cell apoptosis

Explanation

Pembrolizumab and nivolumab are anti-PD-1 monoclonal antibodies. By blocking the PD-1 receptor on T cells, they prevent PD-L1/PD-L2 (expressed by tumour cells and stromal cells) from delivering the inhibitory 'don't attack' signal to tumour-infiltrating lymphocytes, thereby restoring cytotoxic T-cell activity within the tumour microenvironment. Ipilimumab blocks CTLA-4/B7 interaction; anti-LAG-3 (relatlimab) and anti-TIM-3 agents are emerging checkpoint inhibitors.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.