• si-544 was well tolerated with no serious adverse effects, dose limiting toxicities, or safety signals observed
  • 75% of patients receiving si-544 experienced objective clinical improvement, of which 44% achieved clear or almost clear skin

SAN DIEGO, CA, USA, and MUNICH, Germany I April 29, 2024 I selectION, Inc., a clinical-stage biopharmaceutical company developing novel treatments for T-cell mediated autoimmune diseases, today announced positive results from the first-in-human Phase 1b trial of its lead compound, si-544, in atopic dermatitis patients. si-544 is a selectivity-optimized peptide blocking the ion channel Kv1.3.

The completed Phase 1b trial was a multi-center, double-blind, placebo-controlled study in patients with mild to severe atopic dermatitis. The trial was designed to evaluate safety, tolerability, and efficacy signals of si-544.

si-544 was well tolerated up to the highest dose levels in the single ascending dose cohorts (s.c.) and in the multiple ascending dose cohorts (s.c.). Safety signals or dose limiting toxicities were not observed. Of note, limits of safety and tolerability were not reached at the highest doses administered in the study, therefore the maximum tolerated dose was not determined. There were no serious adverse events and no dose reductions or temporary / permanent discontinuations of dosing due to adverse events.

75% of patients receiving drug experienced objective clinical improvement, and of these patients, 44% achieved clear or almost clear skin at the end of the monitoring period. The healing trend clearly continued beyond dosing through the entire monitoring period.

“The ion channel Kv1.3 controls the activation and proliferation of auto-reactive effector memory T-cells and has been regarded a key target in T-cell autoimmunity for decades,” said Andreas Klostermann, PhD, Chief Scientific Officer and co-founder of the Company. “So far, it has not been possible to block this ion channel with sufficient selectivity. The initial analysis of safety and tolerability data from 27 patients in the SAD and MAD cohorts confirms that si-544 can be safely administered at dose levels sufficient to achieve virtually full Kv1.3 target engagement. It also demonstrates that our high-affinity Kv1.3-blocking peptide, si-544, has class-leading selectivity. To our knowledge, selectION is the first to achieve these important goals.”

“Based on the results of this first clinical trial, we believe that si-544 has the potential to set a new benchmark for safety and tolerability in the treatment of T-cell autoimmunity,” said Antonius Schuh, PhD, Chairman and CEO of selectION, Inc. “Study results indicate a clear initial efficacy signal. In addition, under continuous dosing no indication of immunosuppression has been observed. We are now planning to advance si-544 through clinical development and evaluate the compound in further autoimmune diseases.”

About selectION, Inc.
selectION, Inc., is a clinical-stage biopharmaceutical company developing novel peptide therapies for autoimmune diseases and selected cancer indications by targeting autoreactive, chronically activated T-cells.

The Company has established an efficient, unique technology platform to develop potent and highly selective peptide blockers for ion channels involved in various diseases. The platform enables systematically optimized target selectivity, providing the opportunity to develop drugs with significantly improved efficacy and safety profiles.

selectION, Inc., is supported by SDL Ventures and Global Source Ventures. The Company is headquartered in San Diego, CA, USA, with a clinical R&D subsidiary in Munich/Martinsried, Germany.

For further information, please visit https://selectiontherapeutics.com/

About si-544
si-544, the Company´s lead drug candidate, is blocking Kv1.3, a specific ion channel involved in the activation and proliferation of TEM cells, with what we believe to be class leading selectivity. TEM cells lie at the root of many autoimmune indications such as atopic dermatitis, psoriasis, rheumatoid arthritis, or multiple sclerosis, but also of certain rare cancers like lymphomas.

si-544 has demonstrated an excellent safety and tolerability profile in a recently completed Phase 1b clinical trial in atopic dermatitis patients, with study results also indicating a clear initial efficacy signal. Previously, si-544 has demonstrated excellent efficacy in animal and human T-cell models.  

The compound is a potent immuno-selective agent addressing a significant unmet medical need by functionally inhibiting and eliminating disease-specific, chronically activated TEM cells while maintaining full immunocompetence.