Local drugmakers have begun a competition to secure their portion of South Korea’s prostatic hyperplasia and hair loss medication market, as the last of GlaxoSmithKline’s Korean patents on Avodart (dutasteride) expired Thursday.

Avodart is a drug able to treat both enlarged prostate gland symptoms as well as hair loss. GSK had held a separate patent for each of the drug’s two therapeutic effects, veering off competition.

GSK’s local patent on the drug’s ability to treat the former symptom expired in September 2015, while its patent on the latter symptom expired Thursday, fully opening the floodgates to generic competition.

As of Wednesday, a total of 35 Avodart generics produced by Korean pharmaceutical companies have earned local sales approval, according to the Ministry of Food and Drug Safety.

Hanmi Pharmaceutical, Daewoong Pharmaceutical and Dong-A ST are among those that have launched their Avodart generics in line with the original’s patent expiration date.

Generics, exact replications of the original drug’s chemical composition, find their competitive edge in lower pricing. While Avodart is priced at roughly 927 won ($0.77) per capsule, JW Pharmaceutical’s generic is priced at 700 won, Hanmi’s at 756 won and Chong Kun Dang Pharm’s at 840 won per capsule.

The introduction of these cheaper copycat drugs is slated to drive down Avodart’s prices as well as bring down GSK’s market share in the two related treatment arenas.

Avodart’s annual sales stood at 38 billion won as of 2015, of which an estimated 30 billion were from prescriptions for treating prostatic hyperplasia. The remaining was for hair loss treatment purposes, according to the London-based drugmaker.

As the segment leader, Avodart currently takes up some 35 percent of the domestic prostatic hyperplasia medication sector, valued at about 200 billion won, according to GSK.

The drug also makes up about 20 percent of the local hair loss treatment market, valued at 80 billion won. Avodart is currently tailing behind segment leader MSD’s Propecia (finasteride) which boasts about 40 percent market share locally.

This sales dynamic is now set to shift, as Avodart generics may steal away a sizeable portion of the two markets previously dominated by Avodart as well as Propecia and Propecia generics.

“The patent expiration and the introduction of generics were expected. Given that GSK is the original developer of the drug, we believe consumers will continue to prefer our product (Avodart),” a GSK Korea spokesperson said.

“Though the prices of original Avodart and general sales will undoubtedly decline, we also believe that the general market for the drug will expand with the introduction of the generics,” he said.

Nonetheless seeking to protect its local market share, GSK has sealed a partnership with Teva-Handok Pharma to sell its own generic version of Avodart, produced under the same facilities and production methods as those of the original drug, according to GSK Korea.

By Sohn Ji-young (jys@heraldcorp.com)