Keytruda's Main Patent Expiry
Keytruda (pembrolizumab), Merck's blockbuster PD-1 inhibitor for cancers like melanoma and lung cancer, has its core composition of matter patent (US 8,354,509) expiring on December 9, 2028 in the US. This covers the antibody itself and is the primary barrier to generics.[1][2]
When Do Other Key Patents Expire?
Several related patents extend protection:
- Formulation patents (e.g., US 9,220,779) expire April 9, 2035.
- Method-of-use patents for specific cancers, like NSCLC, run to 2034-2036.
- Pediatric exclusivity could push the effective date for generics to June 2029.[1][3]
| Patent Type | Key US Patent # | Expiry Date |
|-------------|-----------------|-------------|
| Composition of Matter | 8,354,509 | Dec 9, 2028 |
| Combination Therapy | 9,220,779 | Apr 9, 2035 |
| Dosing Regimen | 10,093,749 | Oct 30, 2034 |
Biosimilar Entry Timeline
Biosimilars can't launch until after the '509 patent expires in 2028, but Merck has sued challengers like Samsung Bioepis and Viatris. FDA approved the first Keytruda biosimilar (Semglee-like) in 2024, but launches await court rulings—likely 2029 at earliest.[2][4]
Impact on Pricing and Sales
Keytruda generated $25B in 2023 sales. Post-2028 expiry could cut US prices 30-50%, similar to Humira. Merck forecasts $28B peak sales in 2028 before erosion.[3][5]
Who Is Challenging Keytruda Patents?