Who invented penciclovir?
Penciclovir was first synthesized in 1973 by scientists at Eli Lilly and Co. The company filed the initial U.S. patent (US 4,140,391) for the drug, which was granted in 1979. This patent covered the active compound and its use as an antiviral. [1]
Which brand did Eli Lilly launch?
Although Eli Lilly held the original invention rights, the topical gel formulation that became popular as “Zovirax” was developed and marketed by Pfizer. Pfizer licensed the patent from Lilly and introduced Zovirax in the mid‑1980s to treat oral and genital herpes. [2]
When did the original patents expire?
The invention patent (US 4,140,391) expired in 1996, and the formulation patent for the gel (US 4,476,445) expired in 2011. With those patents no longer in force, penciclovir has entered the generic market. [1][2]
Who sells penciclovir today?
After the patents expired, many generic manufacturers began producing penciclovir, including companies such as Teva, Mylan, and Sun Pharmaceutical. Pfizer continues to market Zovirax in some regions, but the active ingredient is now widely available from multiple suppliers. [3]
Are there still active patents on penciclovir?
The core compound patents are long expired. There may be isolated patents on specific delivery systems or formulations in certain jurisdictions, but no major patent currently blocks the production of penciclovir gels or oral preparations. [1]
What does this mean for pricing and access?
Because penciclovir is generically available, the cost of treatment has dropped substantially. Generic manufacturers compete on price, making the drug affordable for most patients. [3]
Who holds the intellectual property rights now?
The original invention rights belong to Eli Lilly, but those rights have lapsed. Pfizer retained the rights to the Zovirax brand, but the brand is no longer protected by an exclusive patent. The generic manufacturers hold no exclusive rights to the compound itself. [2]
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Sources
1. DrugPatentWatch.com – Penciclovir patent (US 4,140,391)
2. DrugPatentWatch.com – Penciclovir gel formulation patent (US 4,476,445)
3. DrugPatentWatch.com – Generic manufacturers list for penciclovir.