Sundance Biosciences Announces Presentation of Phase 1 Results for SUN-627, a Brain-Penetrant TYK2 Inhibitor for the Treatment of Multiple Sclerosis (MS)
SUN-627 demonstrated favorable safety, tolerability, and pharmacokinetics for oral, once-daily dosing in healthy
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SUN-627 demonstrated favorable safety, tolerability, and pharmacokinetics for oral, once-daily dosing in healthy volunteers
Achieved full central nervous system (CNS) penetration and >90% inhibition of TYK2 pathway biomarkers
Brain-penetrant TYK2 inhibitor’s ability to target key CNS-resident immune cells implicated in progressive forms of MS is demonstrated in preclinical results, also presented at Joint ACTRIMS-ECTRIMS Meeting
SOUTH SAN FRANCISCO, Calif., Oct. 21, 2026 (GLOBE NEWSWIRE) — Sundance Biosciences, a biotechnology company advancing next-generation TYK2 (tyrosine kinase 2) inhibitors for individuals suffering from multiple sclerosis (MS) and other immune-mediated diseases, today announced the presentation of Phase 1 results for SUN-627, a potent, highly-selective, brain-penetrant, oral allosteric TYK2 inhibitor in development to treat progressive forms of MS. In the Phase 1 study, SUN-627 demonstrated near complete (>90%) inhibition of the TYK2 pathway for 24 hours with a once-daily dose and full central nervous system (CNS) penetration, along with favorable safety and tolerability in healthy volunteers. The company also announced the presentation of data from preclinical studies demonstrating the impact of TYK2 inhibition on targeting CNS-resident immune cells implicated in the neuroimmune pathology of progressive forms of MS. The two poster presentations are included at the 10th Joint ACTRIMS-ECTRIMS Meeting, taking place October 21-23 in Toronto, Canada.
“The clinical and preclinical results from our studies to date give us confidence in our path forward with SUN-627. We are excited to advance SUN-627 as a novel and potentially best-in-class treatment approach for progressive forms of MS, an area with significant unmet medical need,” said Andrew Yost, Chief Executive Officer of Sundance Biosciences. “Our Phase 1 data support SUN-627 as a highly potent, selective, and brain-penetrant TYK2 inhibitor. Our preclinical results support brain-penetrant TYK2 inhibition as a mechanism that is uniquely capable of addressing the neuroinflammation behind the blood-brain barrier that is a hallmark of progressive forms of MS and is not addressed by current standard of care.”
The SUN-627 Phase 1 trial was a randomized, double-blind, placebo-controlled, single-ascending and multiple-ascending dose clinical trial designed to evaluate the safety, tolerability and pharmacokinetics of oral, once-daily SUN-627 in adult healthy volunteers. The trial also included a dedicated cohort to assess pharmacokinetics in the cerebrospinal fluid (CSF) of healthy volunteers. Key findings include:
- SUN-627 was well-tolerated in healthy volunteers. There were no serious adverse events and all treatment-related adverse events were grade 1 (mild).
- SUN-627 demonstrated near complete inhibition of the TYK2 pathway, achieving greater than 90% reduction of key TYK2 pathway biomarkers for 24 hours with a once-daily dose, as well as a CNS-penetration ratio of 1 (unbound SUN-627 in CSF : unbound SUN-627 in plasma).
- Steady-state CSF exposure of SUN-627 is predicted to remain above the preclinically derived iPSC-microglial IC90 for ~24 hours at doses ≥40 mg once-daily.
Preclinical data presented by Sundance at the ACTRIMS-ECTRIMS Meeting included key mechanistic findings in experimental autoimmune encephalomyelitis (EAE), a widely utilized rodent model of MS, and cell culture experiments. Key results demonstrated that TYK2 inhibition is able to target CNS-resident immune cells that are implicated in progressive forms of MS:
- Direct impact of a brain-penetrant TYK2 inhibitor was shown on interferon-enriched activated microglia and astrocytes, which are resident in chronic active lesions that are a key feature of progressive MS pathology.
- Brain-penetrant TYK2 inhibition impeded interferon-dependent dendritic cell differentiation and antigen-meditated T cell activation, which drives smoldering neuropathology in MS.
“SUN-627’s ability to fully penetrate the CNS and demonstrate significant and sustained inhibition of the TYK2 pathway over 24 hours is highly encouraging,” said Steve Wood, Chief Scientific Officer of Sundance Biosciences. “Preclinical studies have demonstrated that brain-penetrant TYK2 inhibition targets key cell types implicated in progressive forms of MS that are not well-addressed by other therapeutic modalities. This unique profile differentiates SUN-627 from other therapeutic approaches for the treatment of progressive forms of MS and highlights its potential to make a significant impact for people with MS and other neuroinflammatory diseases.”
Preclinical studies performed by the Sundance team have shown that brain-penetrant TYK2 inhibition reverses disease and reduces key markers of neuroinflammation and neurodegeneration in the EAE model of MS. In addition to reversal of disease, achieving brain-penetrant TYK2 inhibition results in dampening of microglial and astrocytic activation, and a reduction in harmful downstream cytokines, chemokines, and markers of neurodegeneration / de-myelination.1
About SUN-627
SUN-627 is an internally discovered, potent, highly-selective, brain-penetrant oral allosteric TYK2 inhibitor with best-in-class potential being developed for neuroimmunology conditions, including progressive forms of multiple sclerosis (MS). Human genetics support TYK2 as a therapeutic target in MS through demonstration that a naturally occurring, partial loss-of-function genetic variant of TYK2 confers significant protection against the disease. SUN-627’s brain-penetrant TYK2 inhibition is designed to treat progressive forms of MS by dampening B cell and T cell signaling, astrocyte activation, and microglial activation behind the blood-brain barrier, resulting in downstream regulation of chemokines and cytokines that drive neuroinflammation. This broad inflammatory regulation has potential to provide significant benefit to patients with progressive forms of MS by directly impacting chronic neuroinflammation that is closely associated with disease progression. Brain-penetrant TYK2 inhibition also has broader therapeutic potential in additional neuroinflammatory conditions such as Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis (ALS).
About Sundance Biosciences
Sundance Biosciences is a clinical-stage biotechnology company dedicated to discovering and advancing next-generation therapies targeting tyrosine kinase 2 (TYK2), a non-receptor intracellular signaling kinase that plays an important role in regulating the immune system, to meaningfully impact the lives of individuals suffering from multiple sclerosis and other immune-mediated diseases. The Company’s two lead clinical programs are SUN-627, a brain-penetrant TYK2 inhibitor in Phase 2 development for progressive forms of MS, and SUN-111, a Phase 2-ready, peripherally-restricted TYK2 inhibitor for immune-mediated diseases. Sundance is led by a team of experienced drug developers and scientists and is backed by top healthcare investors. For more information, please visit www.sundancebio.com.
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1 Molitor, et al. Central TYK2 inhibition identifies TYK2 as a key neuroimmune modulator. PNAS 2025
Media Contact: Kathryn Morris The Yates Network LLC 914-204-6412 kathryn@theyatesnetwork.com
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