Treating Hepatitis C with Combination Drug Therapy
A Gilead Sciences patent detailing a method to treat Hepatitis C by combining a specific chemical compound with an NS5a inhibitor.
Original patent title: “Nucleoside phosphoramidate prodrugs”
A Gilead Sciences patent detailing a method to treat Hepatitis C by combining a specific chemical compound with an NS5a inhibitor. Granted to Gilead Pharmasset LLC in 2014 with 3 claims and 42 forward citations.
Key facts
Coverage
What does this patent actually cover?
This patent describes a medical treatment for Hepatitis C that uses a two-part drug strategy. It requires the administration of an NS5a inhibitor alongside a specific type of chemical compound known as a nucleoside phosphoramidate prodrug. The patent defines the precise molecular structure of this prodrug, including various side chains and chemical groups that allow the drug to be effective. By combining these two distinct types of inhibitors, the treatment aims to disrupt the Hepatitis C virus's ability to replicate in the human body.
The gap
What does this patent NOT cover?
- Does not cover the use of the phosphoramidate prodrugs as a standalone treatment.
- Does not cover chemical structures that fall outside the specific R1, R2, R3, R4, R7, and R8 substituent definitions provided.
- Does not cover treatments for viral infections other than Hepatitis C.
- Does not cover the synthesis of the NS5a inhibitor itself.
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 a 'prodrug'—a biologically inactive compound that the body converts into the active medicine—specifically designed to bypass the rate-limiting step of drug activation inside the liver cells, which was a major hurdle for earlier nucleoside-based antivirals.
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
Sovaldi (sofosbuvir)
Harvoni (ledipasvir/sofosbuvir)
Why it matters
The bigger picture
This patent is central to the development of highly effective direct-acting antivirals for Hepatitis C. It represents the shift toward combination therapies that have made Hepatitis C a curable disease rather than a chronic, lifelong condition. The technology is foundational to the commercial success of blockbuster drugs like Sovaldi and Harvoni.
Filed
October 18, 2013
Granted
May 27, 2014
Market context
Who's building on this
Companies in this space
Gilead Sciences remains the primary entity utilizing this technology. Other pharmaceutical companies have developed competing direct-acting antivirals, but the specific phosphoramidate prodrug chemistry claimed here remains a benchmark in the field.
Market impact
This patent enabled the creation of a multi-billion dollar market for curative Hepatitis C treatments. It fundamentally changed the standard of care, moving away from interferon-based therapies that had severe side effects and lower success rates, effectively turning a global health crisis into a manageable and curable condition.
Claim 1 — Plain English
What this patent covers
This patent describes a medical treatment for Hepatitis C that uses a two-part drug strategy. It requires the administration of an NS5a inhibitor alongside a specific type of chemical compound known as a nucleoside phosphoramidate prodrug. The patent defines the precise molecular structure of this prodrug, including various side chains and chemical groups that allow the drug to be effective. By combining these two distinct types of inhibitors, the treatment aims to disrupt the Hepatitis C virus's ability to replicate in the human body.
The clever bit
The innovation lies in using a 'prodrug'—a biologically inactive compound that the body converts into the active medicine—specifically designed to bypass the rate-limiting step of drug activation inside the liver cells, which was a major hurdle for earlier nucleoside-based antivirals.
What it does not cover
- Does not cover the use of the phosphoramidate prodrugs as a standalone treatment.
- Does not cover chemical structures that fall outside the specific R1, R2, R3, R4, R7, and R8 substituent definitions provided.
- Does not cover treatments for viral infections other than Hepatitis C.
- Does not cover the synthesis of the NS5a inhibitor itself.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
PatentBrief Score
Impact Score
Moderate
Citation count
33/40
Moderately cited
Claim breadth
2/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
5/20
Granted 10–20 years ago
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
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
$270K – $864K
Midpoint $540K · 7.3 yr remaining · 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
3 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Sofia, M. J., Nagarathnam, D., Wang, P., & Du, J. (2014). Treating Hepatitis C with Combination Drug Therapy (U.S. Patent No. 8,735,372). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/8735372/sovaldi-sofosbuvir-composition
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 Treating Hepatitis C with Combination Drug Therapy cover?
A Gilead Sciences patent detailing a method to treat Hepatitis C by combining a specific chemical compound with an NS5a inhibitor.
Who owns patent US 8735372?
Gilead Pharmasset LLC owns this patent, granted in 2014.
When does this patent expire?
This patent is expected to expire on May 27, 2034, when the invention enters the public domain.
What is patent US 8735372 cited by?
This patent has been cited by 42 later patents that build on its ideas.
What problem does this patent solve?
This patent is central to the development of highly effective direct-acting antivirals for Hepatitis C. It represents the shift toward combination therapies that have made Hepatitis C a curable disease rather than a chronic, lifelong condition. The technology is foundational to the commercial success of blockbuster drugs like Sovaldi and Harvoni.
What does this patent NOT cover?
Does not cover the use of the phosphoramidate prodrugs as a standalone treatment.
Same assignee
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