1ST Bio and SK Biopharma ink $314.8m Parkinson's licence for 1ST-104
1ST Biotherapeutics and SK Biopharmaceuticals have signed an exclusive global licensing agreement for 1ST-104, a preclinical oral small-molecule candidate targeting Parkinson's disease, in a deal structured at up to $314.8 million including development and commercial milestones. SK Biopharmaceuticals has also made a $2.2 million strategic equity investment in the South Korea-based drug discoverer to underpin what both parties describe as a long-term partnership.
Under the financial terms, 1STBIO receives an upfront payment of $1.8 million, a further $1.8 million on candidate selection, and tiered royalties on net global sales upon commercialisation. The headline $314.8 million figure encompasses all milestone payments and is therefore a ceiling rather than a guaranteed sum, as is standard in biopharmaceutical licensing structures of this type.
The science behind 1ST-104
The compound is being positioned as a second-generation LRRK2 inhibitor. LRRK2 mutations are among the most common genetic contributors to Parkinson's disease, making the kinase a well-validated target. Earlier Type 1 LRRK2 inhibitors encountered a significant obstacle in development: pulmonary changes observed in preclinical models, an effect thought to be linked to the binding mode rather than the target itself. 1STBIO's approach uses a Type 2 binding conformation, which the company says avoids the mechanism underlying those findings. In preclinical studies, 1ST-104 has shown target selectivity and blood-brain barrier permeability, both prerequisites for a CNS-directed oral drug.
The programme also incorporates dual inhibition of c-Abl, a kinase implicated in neuronal degeneration. 1STBIO already has clinical experience with a standalone c-Abl inhibitor, FB-101, which has completed a Phase 1 single ascending dose study in the United States. That background provides at least partial human pharmacology data relevant to one arm of 1ST-104's mechanism.
Jamie Jae Eun Kim, chief executive of 1ST Biotherapeutics, said the agreement "marks a major milestone by uniting our early-stage R&D strength with SK Biopharmaceuticals' proven global development and commercial expertise." SK Biopharmaceuticals chief executive Donghoon Lee framed the collaboration as combining discovery capability with clinical development and commercialisation infrastructure.
Market and competitive context
The Parkinson's disease drug market is attracting renewed attention from mid-size and large biopharma alike, partly driven by advances in genetic understanding of the disease. Several companies are pursuing LRRK2-targeted strategies, including Denali Therapeutics and Biogen, which have disclosed clinical-stage LRRK2 programmes. The Type 2 inhibitor approach that 1STBIO is championing is less crowded than the Type 1 field, and if preclinical safety data translate to humans without the pulmonary findings seen with earlier candidates, it could offer a meaningful differentiation point.
SK Biopharmaceuticals brings established CNS commercial capability to the deal. The company independently developed cenobamate, marketed as XCOPRI for partial-onset seizures, demonstrating an ability to take a CNS candidate through regulatory approval and into the US market without a larger partner. That track record is meaningful context for a programme that is still pre-IND; the licensing partner here is not simply a funder but a company with end-to-end CNS execution experience.
1STBIO's membership of the LRRK2 Investigative Therapeutics Exchange, a Michael J. Fox Foundation-supported consortium, also signals scientific credibility and access to cross-industry data sharing on LRRK2 biology, which could accelerate candidate optimisation.
The next near-term milestone for observers will be the formal candidate selection that triggers the first milestone payment, followed by IND-enabling studies and, ultimately, a first-in-human trial. SK Biopharmaceuticals has not disclosed a projected timeline for any of these events.