Pembrolizumab was originally studied as a monotherapy - a single agent given on its own. A large proportion of subsequent clinical development has focused on combinations: pairing it with chemotherapy, targeted therapy, or other immunotherapy drugs to improve response rates and expand the populations who benefit.
Pembrolizumab plus chemotherapy
The most established combination approach pairs pembrolizumab with standard chemotherapy regimens. The rationale is that chemotherapy kills tumour cells, releasing tumour antigens and creating an inflammatory environment that enhances the immune response pembrolizumab is trying to generate.
KEYNOTE-189 established the combination in non-squamous NSCLC, regardless of PD-L1 score. KEYNOTE-522 demonstrated significant benefit from pembrolizumab plus chemotherapy in early triple-negative breast cancer. KEYNOTE-590 established the combination in oesophageal cancer. Across these settings, adding pembrolizumab to chemotherapy has consistently improved survival outcomes compared to chemotherapy alone.
Pembrolizumab plus targeted therapy
Pembrolizumab has also been combined with targeted therapies - drugs that act on specific molecular pathways. The most notable approved example is pembrolizumab combined with lenvatinib (a tyrosine kinase inhibitor) in endometrial carcinoma and renal cell carcinoma. KEYNOTE-775 showed a significant survival benefit for this combination in advanced endometrial cancer, particularly in patients without MSI-H tumours - a population that historically had limited treatment options.
In HER2-positive gastric cancer, pembrolizumab is combined with trastuzumab (a HER2-targeted antibody) and chemotherapy, following evidence from KEYNOTE-811.
Dual checkpoint blockade
Combining pembrolizumab (PD-1 inhibitor) with ipilimumab (CTLA-4 inhibitor) targets two separate immune checkpoints simultaneously. This approach is more established in nivolumab-based regimens (nivolumab plus ipilimumab in melanoma and NSCLC) than with pembrolizumab specifically, but the principle is the same: blocking two inhibitory pathways produces a stronger immune activation than either agent alone. The trade-off is a meaningfully higher rate of serious immune-related side effects.
What this means for home-based treatment
Some combination regimens remain hospital-based - particularly those involving IV chemotherapy infusions. Pembrolizumab monotherapy or pembrolizumab as the immunotherapy component of a regimen where other agents have been completed is where home administration is most applicable. An oncologist will advise on which components of any combination regimen can safely be delivered at home.
Receiving combination treatment and wondering about home options?
Our eligibility check takes three minutes and an oncologist reviews it within 24 hours. We can advise on whether the pembrolizumab component of your regimen could be delivered at home.
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