How Genentech Purifies Therapeutic Antibodies for Cancer Treatment
A method for refining mixtures of anti-HER2 antibodies to ensure that harmful acidic variants remain below 25 percent of the total composition.
Original patent title: “Protein purification”
A method for refining mixtures of anti-HER2 antibodies to ensure that harmful acidic variants remain below 25 percent of the total composition. Granted to Genentech Inc in 2002 with 4 claims and 128 forward citations.
Key facts
Coverage
What does this patent actually cover?
This patent describes a process for purifying therapeutic proteins, specifically anti-HER2 antibodies, using ion exchange chromatography. The core mechanism involves adjusting the conductivity and pH levels of buffer solutions to separate the desired antibody from unwanted acidic variants. By carefully controlling these chemical conditions, the process ensures that the final mixture contains less than 25 percent of these acidic byproducts, which is critical for maintaining the safety and efficacy of the drug.
The gap
What does this patent NOT cover?
- Does not cover general protein purification methods that do not specifically target anti-HER2 antibodies.
- Does not cover purification techniques that rely solely on size-exclusion chromatography rather than ion exchange.
- Does not cover compositions where the acidic variant concentration exceeds the 25 percent threshold.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The innovation lies in using precise conductivity and pH gradients to resolve subtle structural differences between a therapeutic antibody and its acidic variants, which are often nearly identical in size.
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Herceptin (trastuzumab) manufacturing processes
Monoclonal antibody production lines
Biopharmaceutical quality control protocols
Why it matters
The bigger picture
This patent is foundational for the production of monoclonal antibody therapies like Herceptin. By establishing strict purity standards for these complex biological molecules, it helped define the manufacturing quality control processes now standard in the biopharmaceutical industry.
Filed
October 3, 2000
Granted
January 15, 2002
Market context
Who's building on this
Companies in this space
Genentech, now a member of the Roche Group, continues to refine these purification techniques. Major biopharmaceutical manufacturers like Amgen and AbbVie also utilize similar ion exchange chromatography workflows to meet regulatory purity requirements for biologic drugs.
Market impact
This patent helped solidify the manufacturing standards for the first generation of targeted cancer therapies. It enabled the large-scale, consistent production of high-purity antibodies, which was essential for the commercial viability and regulatory approval of blockbuster drugs like Herceptin.
Claim 1 — Plain English
What this patent covers
This patent describes a process for purifying therapeutic proteins, specifically anti-HER2 antibodies, using ion exchange chromatography. The core mechanism involves adjusting the conductivity and pH levels of buffer solutions to separate the desired antibody from unwanted acidic variants. By carefully controlling these chemical conditions, the process ensures that the final mixture contains less than 25 percent of these acidic byproducts, which is critical for maintaining the safety and efficacy of the drug.
The clever bit
The innovation lies in using precise conductivity and pH gradients to resolve subtle structural differences between a therapeutic antibody and its acidic variants, which are often nearly identical in size.
What it does not cover
- Does not cover general protein purification methods that do not specifically target anti-HER2 antibodies.
- Does not cover purification techniques that rely solely on size-exclusion chromatography rather than ion exchange.
- Does not cover compositions where the acidic variant concentration exceeds the 25 percent threshold.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
PatentBrief Score
Impact Score
Strong
Citation count
40/40
Highly cited
Claim breadth
3/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
20/20
Major company or institution
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$108K – $346K
Midpoint $216K · expired or expiring · industry ×3.0
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
The original legal language
Original claims
4 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Basey, C. D., & Blank, G. S. (2002). How Genentech Purifies Therapeutic Antibodies for Cancer Treatment (U.S. Patent No. 6,339,142). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/6339142/rituxan-rituximab
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Genentech Purifies Therapeutic Antibodies for Cancer Treatment cover?
A method for refining mixtures of anti-HER2 antibodies to ensure that harmful acidic variants remain below 25 percent of the total composition.
Who owns patent US 6339142?
Genentech Inc owns this patent, granted in 2002.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 6339142 cited by?
This patent has been cited by 128 later patents that build on its ideas.
What problem does this patent solve?
This patent is foundational for the production of monoclonal antibody therapies like Herceptin. By establishing strict purity standards for these complex biological molecules, it helped define the manufacturing quality control processes now standard in the biopharmaceutical industry.
What does this patent NOT cover?
Does not cover general protein purification methods that do not specifically target anti-HER2 antibodies.
Same assignee
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