The assignee ranking for this dataset covers 100 companies across 1,094 records, and it is led by a single assignee with 74 records, well ahead of the fifth-ranked holder at 47. The top five assignees combined hold 27.2% of all 1,094 records in scope, and the top ten reach 42.8%. Beyond that, the ranking has a long tail of assignees with only a handful of filings each, so no single company controls a majority of the claim space.

Filing volume peaked at 64 records in 2019 and has since settled lower; across the last fully comparable window, 2021 to 2024, volume moved from 46 to 39 records, a -15% change. The 2025 and 2026 figures in any trend chart look lower still, but that is a publication-lag artefact — patent applications typically publish around 18 months after filing, so the most recent one to two years always understate true activity. Read the 2021-2024 comparison as the reliable signal, not the raw tail of the chart.

US8148502B2, assigned to Baxalta GmbH, claims a method for purifying recombinant alpha1-antitrypsin using anion exchange chromatography with a buffer system containing phosphate ions and N-acetylcysteine, loaded from a feed containing at least one cell-culture-derived impurity. It is narrow to that specific buffer chemistry and target molecule rather than to anion exchange polishing broadly. Teams working with different buffer systems, different target proteins, or different impurity profiles are working outside its specific claim language, though a full clearance review should check the claim set in detail rather than relying on the abstract alone.