Will generics be reimbursed before the original drug?

Daewoong, Samjin, and Kyungdong successfully circumvent the formulation patent… All 6 patent challengers win first-instance decisions

Original Taleaje remains unreimbursed, opening the door for generics to preoccupy the market

Competition to launch generic versions of the neuropathic pain treatment Taleaje (mirogabalin) appears to be intensifying in Korea.

Because the original product remains non-reimbursed, if generic drugs successfully launch their drugs early, their companies may obtain reimbursement independently and effectively take control of a largely untapped market for mirogabalin-based neuropathic pain treatments.

According to industry sources on June 15, the Intellectual Property Trial and Appeal Board recently ruled in favor of Daewoong Pharmaceutical, Samjin Pharmaceutical, and Kyungdong Pharmaceutical in passive scope confirmation trials against Daiichi Sankyo Korea regarding Taleaje’s salt and formulation patent.

Last month, Dong-A ST, JW Pharmaceutical, and Huons also succeeded in circumventing the same patent. Excluding HK Inno.N, Dongwha Pharmaceutical, and BC World Pharmaceutical, which voluntarily withdrew their challenges last year, every company that pursued patent litigation has now secured a first-instance victory.

Taleaje is protected by three listed patents. It has been protected by the salt/formulation patent (expires April 2034) that the 6 companies had succeeded in circumventing this time, as well as a compound patent (expires June 2031), and a formulation patent (expires March 2036)

Among these, generic manufacturers have already cleared the salt/formulation patent hurdle and are now expected to target the remaining formulation patent, with the goal of launching products immediately upon expiration of the compound patent in 2031.

One particularly noteworthy aspect of the case is that the original Taleaje product still lacks reimbursement coverage. Daiichi Sankyo obtained approval for four strengths (2.5 mg, 5 mg, 10 mg, and 15 mg) in January 2020. However, the reimbursement listing failed after price negotiations with health authorities broke down. The company has been selling the drug as a non-reimbursed therapy ever since.

If domestic companies succeed in launching generics before reimbursement is secured for the original product, they could potentially establish a market led by generic products rather than the original brand.

Generic manufacturers have already satisfied key requirements for first generic exclusivity, including being among the first to challenge the patent and successfully prevailing in those challenges. In January this year, the Ministry of Food and Drug Safety received 19 generic applications for mirogabalin products, including one application for the 2.5 mg strength and six applications each for the 5 mg, 10 mg, and 15 mg strengths. Industry observers believe the 6 patent challengers likely filed their applications simultaneously, with only 1 company seeking approval for the lowest-dose product.

If these companies also succeed in overcoming the remaining formulation patent and launch in 2031, analysts believe the situation could mirror the case of Otezla (apremilast).

In 2021, Korean generic manufacturers successfully challenged patents covering Amgen’s Otezla, which had never been launched in Korea. After reimbursement negotiations failed, Amgen withdrew the original product from the Korean market in June 2022.

Generic manufacturers subsequently obtained approvals in 2024 and independently pursued reimbursement listing, eventually launching products into what was effectively an uncontested market. Currently, Dong-A ST, Daewoong Pharmaceutical, and DongKoo Bio & Pharma market apremilast products in Korea.

Industry experts believe Taleaje generics may have even greater commercial potential than Otezla generics. Unlike the psoriasis market, which has seen numerous new therapies emerge following Otezla, the neuropathic pain market has seen few innovative treatments introduced in recent years.

The Korean neuropathic pain market is currently estimated at approximately KRW 200 billion annually. Current treatment is dominated by reimbursed products containing ‘pregabalin (Lyrica)’ and ‘gabapentin (Neurontin).’ Taleaje could also compete with COX-2 inhibitors such as celecoxib (Celebrex) and SNRI antidepressants such as duloxetine (Cymbalta).

One of Taleaje’s key advantages is its lower incidence of drowsiness and dizziness compared with existing therapies, rendering it a positive option for physicians treating neuropathic pain. The drug has also demonstrated favorable pain-reduction outcomes in patients with diabetic peripheral neuropathic pain (DPNP).

As a result, Taleaje generated approximately KRW 3.7 billion in sales (as of 2024) without reimbursement. Given that level of commercial performance without reimbursement coverage, industry observers believe patent challenges and first-generic exclusivity rights remain highly valuable opportunities for generic manufacturers.