Yongin, South Korea, September 17, 2026
1ST Biotherapeutics, Inc. (1STBIO) and SK Biopharmaceuticals Co., Ltd. (SKBP) have announced an exclusive global licensing agreement and strategic equity investment partnership to advance 1ST-104, an investigational oral small-molecule candidate being developed for Parkinson’s disease. Under the agreement, the collaboration combines 1STBIO’s early-stage drug discovery capabilities with SK Biopharmaceuticals’ clinical development and commercialization expertise. The overall licensing agreement is valued at up to $314.8 million, including milestone payments, while SK Biopharmaceuticals will make a separate $2.2 million strategic equity investment in 1ST Biotherapeutics. The companies announced the agreement on September 17, 2026, from Yongin, South Korea.
1ST Biotherapeutics Licenses 1ST-104 to SK Biopharma
Under the terms of the agreement, 1ST Biotherapeutics will receive an upfront payment of $1.8 million and could receive additional milestone payments that bring the total potential value of the licensing agreement to $314.8 million. The agreement also provides 1STBIO with eligibility for tiered royalties based on global net sales following commercialization. Separately, SK Biopharmaceuticals is investing $2.2 million in 1STBIO to establish a longer-term strategic partnership between the companies. The licensed program, 1ST-104, is being developed as an oral treatment candidate for Parkinson’s disease. The compound uses a dual-inhibition strategy targeting LRRK2 and c-Abl, two proteins being investigated for their potential roles in Parkinson’s disease biology. The companies plan to use their respective capabilities to advance the candidate through subsequent stages of development.
The agreement represents a combination of biopharmaceutical discovery, drug development, licensing, and strategic investment. For 1STBIO, the partnership provides access to SK Biopharmaceuticals’ development and commercialization capabilities, while SKBP gains rights to a next-generation Parkinson’s disease program originating from 1ST Biotherapeutics’ discovery platform.
Dual LRRK2 and c-Abl Strategy Targets Parkinson’s
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A central scientific feature of 1ST-104 is its simultaneous inhibition of LRRK2 and c-Abl. LRRK2 is a kinase that has been associated with the pathogenesis of Parkinson’s disease and is being investigated as a potential therapeutic target. However, the development of some earlier LRRK2 inhibitors has encountered challenges, including pulmonary findings reported in preclinical studies. 1ST Biotherapeutics developed 1ST-104 as a Type 2 LRRK2 inhibitor, using a different binding mode from conventional Type 1 LRRK2 inhibitors. According to the companies, preclinical studies have demonstrated target selectivity and blood-brain barrier (BBB) permeability for 1ST-104. These findings are preclinical and therefore do not establish safety or efficacy in patients.
The company has also been involved in the LRRK2 Investigative Therapeutics Exchange (LITE) since 2024. The consortium, supported by The Michael J. Fox Foundation for Parkinson’s Research, facilitates scientific and technical collaboration related to LRRK2-targeted Parkinson’s disease research.
SK Biopharma Expands Parkinson’s Disease Pipeline
The licensing agreement expands SK Biopharmaceuticals’ presence in central nervous system drug development. SK Biopharmaceuticals and its U.S. subsidiary, SK Life Science, focus on discovering, developing, and commercializing treatments for central nervous system disorders and oncology. The company independently developed and commercialized XCOPRI® (cenobamate) for partial-onset seizures in adults and continues to develop additional CNS programs. For 1ST Biotherapeutics, the agreement provides a strategic pathway for advancing a Parkinson’s disease candidate through a collaboration with a company experienced in global clinical development and commercialization. 1STBIO is a science-driven biopharmaceutical company focused on neurodegenerative diseases, immuno-oncology, and rare diseases. Its Parkinson’s disease portfolio also includes FB-101, a c-Abl inhibitor that has completed a Phase 1 single ascending dose study in the United States.
The companies said the partnership will combine 1STBIO’s discovery and lead-optimization capabilities with SK Biopharmaceuticals’ clinical development and commercial expertise. The next stages for 1ST-104 will determine whether the preclinical characteristics of the candidate can translate into clinical development. The agreement adds another drug-development collaboration in Parkinson’s disease, with 1ST-104 now positioned for further advancement under SK Biopharmaceuticals’ global development capabilities. The $314.8 million potential licensing value, separate strategic investment, and royalty structure establish a commercial framework around the program while the companies continue evaluating its therapeutic potential.
Source: 1ST Biotherapeutics, SK Biopharmaceuticals press release
