secwatch.observer — SEC 8-K summary
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Issuer:     ENANTA PHARMACEUTICALS INC (ENTA)
CIK:        0001177648
Form:       8-K
Filed at:   2026-10-29T20:05:15+00:00
Accession:  0001193125-26-437774
Event type: litigation
Sentiment:  negative
Materiality: 0.60
Item codes: 8.01
LLM model:  deepseek-v4.1-flash:cloud@v2

UPC invalidates Enanta's EP 4 051 265 patent; Paxlovid infringement action against Pfizer dismissed
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- Unified Patent Court ruled on October 29, 2026 that European Patent No. EP 4 051 265 is invalid, and that Enanta's infringement action was unfounded in light of that holding.
- Enanta had sued Pfizer and subsidiaries in the UPC over Pfizer's manufacture, use and sale of Paxlovid (nirmatrelvir/ritonavir tablets) across the 18 EU member states participating in the UPC.
- Pfizer counterclaimed for revocation of the '265 Patent; a hearing on both the infringement action and the revocation counterclaim was held September 29, 2026.
- The decision removes Enanta's asserted European patent claims against Paxlovid in the UPC jurisdiction, with no injunction or damages awarded to Enanta.

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/1177648/000119312526437774/0001193125-26-437774-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/1177648/000119312526437774/enta-20261029.htm
  HTML page:      https://secwatch.observer/filing/0001193125-26-437774

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