SM-04554

SM-04554, also designated dalosirvat (International Nonproprietary Name), is a synthetic small-molecule activator of the canonical Wnt/beta-catenin signaling pathway developed by Samumed, LLC (subsequently renamed Biosplice Therapeutics, Inc.) as a topical treatment for androgenetic alopecia (AGA). The compound activates Wnt signaling with an EC50 of approximately 28 to 29 nanomolar in cell-based reporter assays, producing increases in total and nuclear beta-catenin, versican expression, and Ki-67 proliferation marker specifically in hair follicle compartments. The molecular formula is C18H16O4 with a molecular weight of 296.32 g/mol; the compound is a 1,4-diketone bearing a 2,3-dihydro-1,4-benzodioxin-6-yl moiety and a terminal phenyl group, conferring moderate lipophilicity (calculated XLogP 2.6) suitable for topical scalp formulation.

The mechanistic rationale for SM-04554 in androgenetic alopecia rests on the observation that Wnt/beta-catenin signaling is essential for the initiation and maintenance of the anagen (growth) phase of the hair cycle and that progressive reduction of Wnt pathway activity in the dermal papilla and hair bulge stem cell niche is a molecular correlate of follicular miniaturization in AGA. SM-04554 activates the pathway downstream of ligand-receptor interaction, increasing nuclear translocation of beta-catenin and transcription of Wnt target genes including those regulating dermal progenitor cell differentiation toward the hair follicle lineage. In preclinical models, topical SM-04554 induced hair follicle neogenesis in CD1 and C57BL/6 mice (2-fold increase in total follicle count after 4 days of treatment) and in Hanford mini-pigs (significant increase in vellus follicle number sustained through 112 days of observation following a 42-day treatment course).

Clinical development proceeded through Phase 1 (29 subjects, 14-day topical application at 0.05%, 0.15%, and 0.45% concentrations), Phase 2 (two studies: a 49-subject biopsy-endpoint trial and a 300-subject efficacy trial, both 90-day treatment), and Phase 3 (625-subject registration trial initiated November 2018 and completed January 2021). The Phase 1 trial demonstrated safety with only one drug-related adverse event (eye irritation at the 0.45% concentration). The Phase 2 program demonstrated statistically significant increases in non-vellus hair count and density at the 0.15% concentration relative to vehicle, with an inverted-U dose-response in which the 0.15% concentration outperformed the higher 0.25% concentration. Adverse events across the Phase 2 program were mild (scalp redness, burning, stinging) and comparable in frequency to vehicle. No serious adverse events were reported in any treated patient across the Phase 2 program. The Phase 3 trial results were not publicly disclosed; Biosplice Therapeutics removed SM-04554 from its development pipeline in 2021, and a 2023 literature review confirmed cancellation of development based on Phase 3 outcomes. The compound is not approved by any regulatory authority.

SM-04554 is one component of a broader Wnt-modulating therapeutic platform developed by Samumed/Biosplice, which includes lorecivivint (SM-04690, a CLK2/DYRK1A kinase inhibitor for knee osteoarthritis) and SM-04755 (a Wnt pathway inhibitor for tendinopathy). The compound is available from multiple research chemical suppliers as a white powder at greater than 99% purity. This monograph reviews the chemistry, Wnt pathway pharmacology, preclinical hair growth models, the complete clinical evidence base across all trial phases, pharmacokinetic considerations for topical delivery, sourcing and handling, stack-interaction considerations, adverse-event profile, and a comparative assessment of five alternative androgenetic alopecia candidates against SM-04554 on five competency standards.