FDA-Approved Indications for Keytruda
Keytruda (pembrolizumab), from Merck, targets multiple cancers as a PD-1 inhibitor that blocks immune evasion by tumor cells. The FDA has approved it for over 30 indications across solid tumors, blood cancers, and specific biomarkers, often in combination with chemotherapy or other therapies. Key approvals include:
- Melanoma: Unresectable or metastatic cases, and adjuvant treatment post-surgery.[1]
- Non-small cell lung cancer (NSCLC): Advanced cases with PD-L1 expression, high tumor mutational burden, or as first-line with chemo; also neoadjuvant/adjuvant settings.[1]
- Head and neck squamous cell carcinoma: Recurrent or metastatic, or combined with chemo/radiation.[1]
- Classical Hodgkin lymphoma: Relapsed or refractory after other treatments.[1]
- Urothelial carcinoma: Advanced cases locally advanced or metastatic.[1]
- Microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) solid tumors: Unresectable or metastatic, including colorectal, endometrial, and others, regardless of tumor type.[1]
- Triple-negative breast cancer: High-risk early-stage or PD-L1-positive metastatic with chemo.[1]
- Esophageal and gastroesophageal junction cancer: Advanced or metastatic.[1]
- Cervical cancer: Persistent, recurrent, or metastatic PD-L1-positive cases.[1]
- Hepatocellular carcinoma: As second-line after sorafenib.[1]
- Merkel cell carcinoma: Recurrent locally advanced or metastatic.[1]
- Renal cell carcinoma: In combination with axitinib for advanced cases.[1]
- Biliary tract cancer: Locally advanced or unresectable with gemcitabine/cisplatin.[1]
- Endometrial carcinoma: Advanced, MSI-H/dMMR, or combined with lenvatinib.[1]
- Tumor mutational burden-high (TMB-H) solid tumors: Previously treated, unresectable or metastatic.[1]
Full list and updates available on the official Keytruda label via FDA.[1]
How Keytruda Works Against These Cancers
It binds PD-1 on T-cells, preventing PD-L1/PD-L2 interaction that tumors use to suppress immunity. Effectiveness hinges on biomarkers like PD-L1 expression (>1-50% thresholds vary by cancer), MSI-H/dMMR (15-20% of cancers), or TMB-H (>10 mutations/megabase). This enables tumor-agnostic approvals for MSI-H/dMMR and TMB-H cancers.[2]
Unapproved or Investigational Uses
Keytruda is in trials for small cell lung cancer, prostate cancer, ovarian cancer, and pancreatic cancer, but lacks full FDA approval there. Off-label use occurs but isn't standard.[2]
Common Patient Questions on Targeting
What if my cancer lacks PD-L1? Response rates drop (e.g., 10-20% vs. 40-50% in PD-L1-high NSCLC), but MSI-H/TMB-H can still qualify.[2]
Does it work in combination? Yes, boosts efficacy in 70% of approvals, like NSCLC (median survival 22 months vs. 11 alone).[3]
How do doctors test eligibility? Via IHC for PD-L1, NGS for MSI/dMMR/TMB.[2]
Patent Status
Keytruda's composition of matter patent expires January 2028 in the US; method-of-use patents extend to 2036 amid challenges. Biosimilars unlikely before 2028. Check DrugPatentWatch.com for litigation updates.[4]
[1]: FDA Keytruda Prescribing Information (fda.gov/drugs).
[2]: Merck Keytruda HCP Site (keytruda.com).
[3]: KEYNOTE Trials (nejm.org, lancet.com).
[4]: DrugPatentWatch.com (drugpatentwatch.com/p/trademark/KEYTRUDA).