Korean drugmakers are seeking to acquire preferential rights to market the generic versions of Gilead Science’s Vemlidy, a Hepatitis B treatment, so that they may preempt the market.
Currently, five companies – DongA-ST, Daewoong Pharmaceutical, Chong Kun Dang, Jeil Pharmaceutical and Dongkwang Pharmaceutical – plan to do so by avoiding Gilead’s composite patent with the base-altering strategy. The five companies have filed a suit to confirm the scope of Vemlidy’s patent.
Their strategy is similar to the product launch of various generic versions of Viread, which is also a Hepatitis B treatment of Gilead, in 2017.
At the time, 16 Korean pharmaceutical companies obtained preferential rights from the government to sell generic versions of Viread by nullifying the substance patent through the invalidation trial, and avoided the composite patent with the base-altering strategy.
With the preferential sales rights, local pharmaceutical companies released their drugs before Viread’s substance patent expires.
Regarding Vemlidy, local companies are likely to develop products using a different composition other than hemifumarate base for their tenofovir ala fenamide (TAF) substance.
The substance patent for Vemlidy will still be valid, but if the Korean companies manage to receive preferential rights to bypass the composition patent through their base-altering strategy, they may launch their product as early as 2022, after the post-marketing surveillance (PMS) for Vemlidy ends. Vemlidy’s PMS finishes on Nov. 12, 2022.
Even if the local pharmaceutical companies receive preferential sales rights, however, it is uncertain that the competition will have a significant impact on the sale for Vemlidy, as Gilead successfully defended off local competition for Viread in the past.
Viread recorded the highest sales among all prescription drugs in 2017 with prescription sales of 166 billion won ($148 million), marking an almost 8 percent jump from the previous year.
Also, local physicians have a good opinion toward the Vemlidy as the Korean Association for the Study of the Liver has recommended the drug as a first-line treatment for chronic hepatitis B in its revised annual guideline in November.
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