Famciclovir

Herpes zoster, as a highly prevalent viral skin disease, not only causes severe neuralgia, but also tends to lead to long-term complications such as postherpetic neuralgia in elderly patients. There is an urgent clinical demand for antiviral drugs with high efficacy and low toxicity. Famciclovir is a second-generation nucleoside anti-herpesvirus drug and a prodrug of penciclovir. After oral administration, it can be rapidly converted into penciclovir with antiviral activity in vivo, and exerts its effect by inhibiting the synthesis of herpes virus DNA. It is mainly used clinically for the treatment of herpes zoster and primary genital herpes, and can also be used for herpes simplex virus infection in patients with normal immune function. It is a first-line drug recommended by current relevant disease guidelines, and the applicable population covers adult patients and some special populations with low immune function.

At present, the global famciclovir market size is approximately USD 180 million, and the market size in China has exceeded RMB 300 million. As the incidence of herpes zoster increases year by year with population aging, the annual compound growth rate of the market remains at around 4.2%. In terms of the competitive landscape, the original research product still occupies part of the high-end market share, and domestic generic drugs have become the main force in the domestic market by virtue of their cost-effectiveness advantages. At present, more than 20 enterprises have obtained the production approval for famciclovir preparations, and the supply of API has basically achieved localization, with no obvious supply gap.

The original research enterprise of famciclovir is Novartis, with the original brand name Famvir, and the core compound patent expired globally in 2010. The main dosage forms approved for the original product include tablets and capsules, with three specifications of 125mg, 250mg and 500mg. The original product has been included in the FDA Reference Listed Drug Catalog and China's *Catalog of Reference Preparations for Chemical Drugs*. In terms of domestic API registration, 12 enterprises' famciclovir APIs have obtained A status through CDE registration, and another 6 are under evaluation. The domestic approved preparation varieties cover multiple dosage forms such as tablets, capsules and dispersible tablets. (Data as of May 2025, please refer to the official CDE website for the latest information)

In response to the R&D and production quality control needs related to famciclovir, CATO can provide a full set of impurity reference standards for this API. The products fully meet the compliance requirements of multiple regulations such as the Chinese Pharmacopoeia and FDA. Most impurities are in stock. Spot products ordered before 16:00 can be shipped on the same day, which can fully meet the full-cycle testing needs of pharmaceutical enterprises in the stages of R&D and declaration as well as mass production.