Virus-retentive filtration (VRF) is a physical size-exclusion step used in biologics manufacturing to remove viral particles from a protein sample without inactivating the product. It typically sits inline with chromatography steps such as hydrophobic interaction chromatography (HIC) in a continuous purification train. In this dataset, every one of the 12 records in scope carries a B01D separation-process classification, confirming that filtration is the consistent technical core of the field regardless of which other purification steps a given patent also claims.

The assignee ranking for this dataset returns only two ranked companies, and together they account for all 12 records in scope — a fully concentrated field with no long tail of smaller filers showing up in the ranking. That said, this is a narrow, targeted search string covering a specific technical combination, not the entire viral clearance field, so the concentration reflects this dataset's scope rather than the industry as a whole. Readers should treat the ranked leader's position as a signal of where claim density is heaviest, not as a complete competitive map.

Filings grew from 3 in 2021 to 5 in 2024, a +67% increase over that three-year span, with 2024 standing as the peak year recorded so far. Filing counts for 2025 and into 2026 are lower, but that is expected: publication typically lags actual filing by around 18 months, so the most recent one to two years in any patent trend are understated until later filings work through examination and publication. The honest read is growth through 2024 with an as-yet-unresolved tail, not a decline.

US20220106358A1, assigned to Regeneron Pharmaceuticals, covers a continuous processing system combining a hydrophobic interaction chromatography column connected inline to a virus retentive filtration system that itself comprises at least two filter trains arranged in parallel. This specific combination — HIC plus inline VRF plus parallel filter trains — is what the claim scope protects, not filtration or HIC in isolation. A team using a single filter train, a different upstream chromatography mode, or a batch rather than continuous architecture would sit outside this particular claim's literal scope, though a full freedom-to-operate review of the granted claims themselves is still necessary before relying on that distinction.

The technology composition data shows several IPC subclasses appearing in only a single record out of the 12 in scope: A47J (kitchen and cooking utensils, likely relevant to single-use vessel design), A61P (therapeutic activity), and C12M (bioreactors and enzyme apparatus). Apparatus-level claims that tie a specific single-use bioreactor or vessel design directly to an integrated virus-retentive filter train appear largely unclaimed in this dataset, in contrast to the dense claim coverage around the inline HIC-plus-VRF system architecture. That gap is where a first claim on apparatus integration, rather than on the filtration chemistry or system architecture itself, would have the most room to stand.