What was the initial cancer indication for keytruda?

Keytruda's Original FDA Approval

Keytruda (pembrolizumab) received its first U.S. FDA approval on September 4, 2014, for unresectable or metastatic melanoma in patients whose tumors express PD-L1, as determined by an FDA-approved test.[1][2]

How the Approval Happened

The approval stemmed from the KEYNOTE-001 trial, a phase 1 study showing 33% objective response rate and 4-month median duration in PD-L1-positive advanced melanoma patients.[1][3] This marked the first PD-1 inhibitor approval, based on accelerated pathways for breakthrough therapies.

Expansion to Other Cancers

Keytruda quickly gained approvals beyond melanoma:
- December 2014: Ipilimumab-refractory melanoma.
- October 2015: Non-small cell lung cancer (NSCLC) expressing PD-L1.
By 2024, it has 40+ indications across 18 tumor types, including MSI-H cancers regardless of location.[1][4]

Why Melanoma First?

Melanoma's high unmet need and PD-1 pathway's role in immune evasion made it the lead; early trials prioritized immunotherapy-resistant cases.[3][5]

Current Status and Patents

Keytruda remains Merck's top seller at $25B+ annual revenue. U.S. composition-of-matter patent expires in 2028, with challenges ongoing; pediatric exclusivity adds six months.[6][1]

[1]: FDA Approval History
[2]: Keytruda Prescribing Information
[3]: NEJM KEYNOTE-001 Results
[4]: Merck Keytruda Indications
[5]: ASCO Post on PD-1 History
[6]: DrugPatentWatch.com - Keytruda Patents