Xofluza, Ongentys generics apply for approval

Roche’s flu treatment Xofluza

Attention is focused on whether market competition will intensify with approval applications being filed for items where no generic drugs have emerged until now.
However, given that the original drugs' patents are registered, overcoming patent barriers is expected to be key for entering the market.
According to the Ministry of Food and Drug Safety (MFDS) on the 2nd, applications for generic versions of the influenza treatment Xofluza Tab (baloxavir marboxil, Roche) and the Parkinson's disease treatment Ongentys Cap (opicapone, SK Chemicals) have recently been submitted for approval.

MFDS has notified the originator companies of the applications in accordance with Korea’s patent–approval linkage system, since the patents for these originators are registered on the Green List.

This gives the originators the right to seek sales injunctions on grounds of patent infringement.

Xofluza is Roche's next-generation influenza antiviral, an upgrade from Tamiflu. While Tamiflu requires a 5-day course, Xofluza offers the advantage of treatment and prevention with just a single dose, providing much improvement in terms of dosing convenience.

However, since receiving domestic marketing approval in November 2019, Xofluza has not yet been listed for reimbursement and therefore is not being sold properly in the market.

Meanwhile, follow-on manufacturers are eyeing the market with generics containing the same active ingredient. Last month, Kwangdong Pharmaceutical filed a passive scope confirmation trial to circumvent Xofluza’s formulation patent (a solid formulation having excellent stability).

This marks the first detected application filing following the patent challenge. Should Kwangdong Pharmaceutical succeed in circumventing the formulation patent, an early launch of generics will become possible.

Ongentys, which was approved the same month as Xofluza, has also been targeted by generic companies. The drug is used as adjunct therapy for Parkinson’s disease patients experiencing motor fluctuations who do not adequately respond to standard levodopa/dopa-decarboxylase inhibitor (DDCI) regimens.

Ongentys was added to the reimbursement list in October last year at KRW 2,515 per capsule. Development of a generic version began less than a year after its reimbursement listing.

Myung In Pharm filed a passive scope confirmation trial in May to challenge Ongentys’ composition patent (pharmaceutical composition containing a nitrocatechol derivative and its manufacturing processes).

Applications filed for generic versions were detected soon after, accelerating the opening of the follow-on generic market.

The market entry of generics for Xofluza and Ongentys hinges on their patents. For Xofluza, 2 substance patents are scheduled to expire in 2031 and 2036, respectively.

Even if companies succeed in avoiding the formulation patent expiring in 2039 through patent challenges, the substance patents are expected to delay generic market entry by another 10 years. Therefore, analysis suggests that overcoming the substance patent barrier is necessary for generics to enter the market sooner and start sales in earnest.

For Ongentys Cap, the substance patent expires in July 2026 and the use patent in October 2027. Therefore, if the composition patent expiring in 2030 is successfully avoided, a generic launch could occur within 2 years.

However, it remains uncertain whether the Patent Trial and Appeal Board will rule in favor of the generic challengers.

Meanwhile, another application has been filed for the generic version of Hanmi Pharmaceutical’s AmosartanQ, for which Huons earlier became the first to receive generic approval in September.

Huons obtained approval for BesylsartanQ Tab, which contains an “alternative salt form” product containing the same active ingredients (amlodipine camsylate+ losartan + rosuvastatin). 

However, the formulation patent for AmosartanQ is expected to remain in force until November 2033, making its market launch uncertain. Huons has filed a passive claim scope confirmation trial against this patent, aiming to circumvent it.

Amid this situation, another pharmaceutical company has now applied for approval of a generic version.