Another salt-modified drug competes with Daewoong's "Jakavi follow-on"

Marketing authorization application for a follow-on drug formulated using a new 'hydrochloride' has been submitted in late July

Possibility of securing priority sales marketing authorization on a separate track for salt modification...both products are expected to compete in the market in early 2027

Product photo of 'Jakavi'

As Daewoong Pharmaceutical secured follow-on drug exclusivity by obtaining priority sales marketing authorization in the generic drug market for Novartis Korea's rare hematologic malignancy treatment 'Jakavi (ruxolitinib phosphate),' another salt-modified product has announced market entry by submitting a marketing authorization application.

​Salt-modified therapeutics are scheduled to be commercialized starting January 15, 2027, after the original drug's patent expires.

​According to the Ministry of Food and Drug Safety (MFDS) on the 26th, a follow-on drug containing 'ruxolitinib hydrochloride' submitted a marketing authorization application to the MFDS in late July and notified the original drug company. This product used a hydrochloride salt rather than the phosphate salt of the originator Jakavi, designed specifically to circumvent the patent.

​Previously, Daewoong Pharmaceutical's salt-modified document-submission drug "Ruxovi Tab (ruxolitinib hemifumarate)" secured priority sales marketing authorization valid for nine months from January 15, 2027, to October 14, 2027.

​Daewoong circumvented the original drug's composition (salt) patent, originally scheduled to expire in June 2028, through a negative scope confirmation trial and structured a strategic indication portfolio that accounted for the remaining post-marketing surveillance (PMS) period for expedited review, thereby capturing both the initial marketing authorization and first-generic exclusivity. Consequently, it can be commercialized after the original drug's substance patent expires on January 14, 2027.

​However, a new variable has emerged in Daewoong Pharmaceutical's exclusive market structure: a follow-on drug containing ruxolitinib hydrochloride, distinct from the existing hemifumarate salt, has been filed for marketing authorization with the MFDS.

​Under South Korea's current patent linkage system, the marketing ban effect held by priority sales marketing authorization applies strictly to 'identical pharmaceuticals' sharing the same active ingredient, dose strength, and dosage form. Because the newly filed product uses ruxolitinib hydrochloride, it contains a different salt than Daewoong Pharmaceutical's ruxolitinib hemifumarate and is legally classified as a distinct pharmaceutical entity.

​Therefore, if the newly submitted product meets patent circumvention requirements and first-to-file criteria, it can be granted its own independent first-generic exclusivity over the same timeframe as Daewoong Pharmaceutical's, enabling joint market entry.

​With annual outpatient prescription sales reaching approximately KRW 9.1 billion (based on 2025 UBIST data), Jakavi is a high-value rare disease treatment, with numerous pharmaceutical companies, including Chong Kun Dang, Samyang Holdings, and Dongkook Pharmaceutical, currently competing in development.  

​An industry official said, "While Daewoong Pharmaceutical first secured first sales marketing authorization, there is a possibility for late-entrant developers utilizing different salts to secure additional exclusive sales rights," adding, "As the substance patent is set to expire in early 2027, competition among salt-modified generics to capture early market share will intensify."