Keytruda (pembrolizumab) is a PD-1 inhibitor that helps the immune system recognize and attack cancer cells. The benefits seen with Keytruda vary by cancer type and by biomarkers, but the overall themes are:
- Longer survival in some settings: In several cancers, Keytruda has shown improvements in overall survival (OS) compared with standard therapies, especially when used in PD-L1–positive tumors or in certain first-line or combination regimens.
- Delayed or durable responses: Some patients experience long-lasting tumor shrinkage or disease control that can persist after treatment ends, which is a notable feature of many immunotherapies.
- Higher response rates in selected groups: Certain cancers and biomarker-defined subgroups (eg, MSI-H/dMMR tumors) have higher response rates to Keytruda.
- Benefit across multiple tumor types: Keytruda is approved for a wide range of cancers and also has a tumor-agnostic approval for MSI-H/dMMR cancers, meaning it can be effective across different tissues if the tumor shows the MSI-H/dMMR biomarker.
- Use as single agent or with chemotherapy: Keytruda can be used by itself (monotherapy) in some settings or in combination with chemotherapy to improve outcomes in others.
How biomarkers influence benefit
- PD-L1 expression: In some cancers, higher PD-L1 expression predicts greater benefit from Keytruda, particularly in monotherapy settings.
- MSI-H/dMMR status: Tumors with MSI-H/dMMR tend to respond better to pembrolizumab, and this is part of the tumor-agnostic approval.
- Tumor mutational burden (TMB) and other factors: May influence likelihood of response in certain contexts.
Examples of where Keytruda has shown benefit (high level)
- Melanoma and non-small cell lung cancer (NSCLC): OS benefit and durable responses in several trials, with greater benefits in biomarker-positive groups or in combination regimens.
- Urothelial (bladder) cancer: OS improvement in patients who progressed after platinum therapy (second-line).
- Head and neck cancer, cervical cancer, and other solid tumors: Trials have demonstrated OS or progression-free survival benefits in various lines of therapy, especially with biomarker selection or in combination with chemotherapy.
- MSI-H/dMMR solid tumors: Tumors across tissue types with this biomarker often show meaningful responses and durable benefit.
Important caveats
- Not every patient or cancer type benefits, and the magnitude of benefit varies by tumor type and biomarkers.
- Immune-related adverse events can occur (eg, inflammation of organs such as lungs, colon, liver, endocrine glands). These require monitoring and sometimes treatment with corticosteroids or other immune-modulating therapies.
- The decision to use Keytruda (and whether it should be used alone or with chemotherapy) depends on cancer type, stage, prior treatments, and biomarker results.
If you tell me the exact cancer type and whether you know the tumor’s biomarker status (PD-L1, MSI-H/dMMR, etc.), I can give more precise, evidence-based examples of expected benefits and relevant trial data. Also, I can point to common side effects to discuss with a clinician.