As well-selling original drugs, including Gilead’s hepatitis B treatment Viread, face patent expirations this year, local drugmakers are doubling efforts to ready their generic drugs.
According to industry sources, drugs nearing patent expiration include Mitsubishi Tanabe's dry eye treatment Diquas-S, Pfizer's osteoporosis therapy Vivant, Roche's anti-cancer drugs Avastin, and Novartis' macular degeneration treatment Lusentis. AstraZeneca's patent for asthma treatment Symbicort Turbuhaler expired on Jan. 13.
Viread marked the largest annual sales at 160 billion won ($150.4 million) in 2017, followed by Avastin with 80 billion won, Lusentis with 20 billion won, Symbicort with 10 billion won, Viviant with 7 billion won, and Diquas-S with 5.5 billion won. All combined, the drugs with expiring patents this year are worth 280 billion won.
Local pharmaceutical firms are paying particular attention to Viread. The drug’s patent in substance expired in November. In November this year, its patent in the base will expire. Since the substance patent expired, many generic drugs appeared in the market. As 27 percent of the Viread prescriptions occurred at clinics, local drugmakers are seeing an attractive opportunity in selling their drugs instead of Viread. As local firms have a stronger sales power at hospitals, they will be able to sell Viread’s copies well, sources said.
The patent of representative dry eye treatment Diquas-S by Mitsubishi Tanabe will expire in July. Although the drug had another patent for the usage for new purposes until November 2021, Hanmi Pharmaceutical, Chong Kun Dang, and Sam Chun Dang Pharm won the patent invalidation lawsuit against Mitsubishi Tanabe in December. Following the suit, local firms were allowed to release generic drugs.
The substance patent of Pfizer’s Viviant will expire in December. Competitors such as MSD Korea’s Fosamax series have come out on the market. Other companies, including Kolmar Korea, Inist Bio Pharmaceutical, and Hyundai Pharma, are preparing for Viviant’s generic drugs.
The patent of AstraZeneca’s Symbicort Turbuhaler in drug stabilization and compounding of ingredients expired on Jan. 13. In 2016, the treatment’s prescription sales reached 11.2 billion won. Duorespi Spiromax by Teva-Handok, which avoided Symbicort Turbuhaler’s patent in 2016 launch, is the only competitor against Symbicort.
When it comes to inhaling devices such as Symbicort, generic drug makers may find it difficult to expect the same effectiveness. However, some analysts said local drugmakers’ advancement in technology would allow them to release rival products. There is no generic drug on the market to compete against Symbicort, except for Duorespi Spiromax.
Biopharmaceutical products Roche’s Avastin and Novartis’ Lusentis will also face substance patent on April 3. Unlike chemical drugs, rivals against the two will be biosimilar drugs by Samsung Bioepis and Celltrion.
Samsung Bioepis is conducting a phase-3 clinical trial on Avastin-referencing biosimilar, and Celltrion, a phase-1 study. To test Lusentis-referencing biosimilars, Samsung Bioepis is in a phase-3 trial, and BIOCND, phase-1.