Han-Oh Park

SRN001 is a small interfering RNA (siRNA) drug targeting amphiregulin. It was developed using a novel SAMiRNA^® platform, in which the siRNAs are protected within a self-assembled micelle. This platform eliminates the need for additional excipients to reduce unintended immune reactions. Amphiregulin plays a critical role in tissue repair and immune modulation. By silencing it, SRN001 is expected to be a therapeutic option for various pathologically fibrotic and cancerous diseases. This study aimed to evaluate safety and pharmacokinetics (PK) of SRN001 in humans for the first time. A randomized, double-blind, placebo-controlled, single ascending dose, Phase 1 trial was conducted (NCT05984992). Participants randomly received a single intravenous dose of SRN001 (15, 45, 135, or 210 mg) or placebo. Safety was assessed with vital signs, clinical laboratory tests, electrocardiograms, and inflammatory cytokine assays (IL-1β, IL-6, IFN-γ, and TNF-α). Serial blood samples were collected until 168 hours post-dose to quantify plasma antisense siRNA concentrations. Anti-drug antibodies (ADAs) were measured at pre-dose, 15 days, and 29 days post-dose. Among 25 participants, SRN001 was generally well tolerated. Unlike other approved siRNA drugs, no systemic symptoms or cytokine elevation suggestive of infusion-related reactions (IRRs) were observed in any subjects receiving SRN001, even without premedication. SRN001 exhibited dose-proportional exposure, with the average AUC_inf of 1.35 ug·hour/mL in the 15 mg dose group, achieving the therapeutic exposure in preclinical studies. The average plasma half-life was 0.48 hours. No ADAs were detected. A single IV administration of SRN001 demonstrated a favorable safety profile and dose-proportional PK in this small first-in-human phase 1 clinical trial. By minimizing the need for excipients, the SAMiRNA platform is anticipated to facilitate the development of safer siRNA drugs in the future. Therapeutic potential of SRN001 will be explored in subsequent clinical trials.

Lee JU, et al. J Korean Med Sci. 2026 Jun;41(25):e185. https://doi.org/10.3346/jkms.2026.41.e185

Fibrotic disorders pose a significant global health burden due to limited treatment options, creating an urgent need for novel therapeutic strategies. Amphiregulin (AREG), a low-affinity ligand for the epidermal growth factor receptor (EGFR), has emerged as a key mediator of fibrogenesis through dual signaling pathways. Unlike high-affinity EGFR ligands, AREG induces sustained signaling that activates downstream effectors and promotes the integrin-mediated activation of transforming growth factor (TGF)-β. This enables both canonical and non-canonical EGFR signaling pathways that contribute to fibrosis. Elevated AREG expression correlates with disease severity across multiple organs, including the lungs, kidneys, liver, and heart. The therapeutic targeting of AREG has shown promising antifibrotic and anticancer effects, suggesting a dual-benefit strategy. The increasing recognition of the shared mechanisms between fibrosis and cancer further supports the development of unified treatment approaches. The inhibition of AREG has been shown to sensitize fibrotic tumor microenvironments to chemotherapy, enhancing combination therapy efficacy. Targeted therapies, such as Self-Assembled-Micelle inhibitory RNA (SAMiRNA)-AREG, have demonstrated enhanced specificity and favorable safety profiles in preclinical studies and early clinical trials. Personalized treatment based on AREG expression may improve clinical outcomes, establishing AREG as a promising precision medicine target for both fibrotic and malignant diseases. This review aims to provide a comprehensive understanding of AREG biology and evaluate its therapeutic potential in fibrosis and cancer.

Fibrotic disorders pose a significant global health burden due to limited treatment options, creating an urgent need for novel therapeutic strategies. Amphiregulin (AREG), a low-affinity ligand for the epidermal growth factor receptor (EGFR), has emerged as a key mediator of fibrogenesis through dual signaling pathways. Unlike high-affinity EGFR ligands, AREG induces sustained signaling that activates downstream effectors and promotes integrin-mediated activation of transforming growth factor (TGF)-β. This enables both EGFR-dependent and -independent mechanisms that contribute to fibrosis. Elevated AREG expression correlates with disease severity across multiple organs, including the lungs, kidneys, liver, and heart. Therapeutic targeting of AREG has shown promising antifibrotic and anticancer effects, suggesting a dual-benefit strategy. Increasing recognition of the shared mechanisms between fibrosis and cancer further supports the development of unified treatment approaches. Inhibition of AREG has been shown to sensitize fibrotic tumor microenvironments to chemotherapy, enhancing combination therapy efficacy. Targeted therapies, such as Self-Assembled-Micelle inhibitory RNA (SAMiRNA)-AREG, have demonstrated enhanced specificity and favorable safety profiles in preclinical studies and early clinical trials. Personalized treatment based on AREG expression may improve clinical outcomes, establishing AREG as a promising precision medicine target for both fibrotic and malignant diseases.

Self-assembled-micelle inhibitory RNA-targeting amphiregulin (SAMiRNA-AREG) is a novel RNA interference-based nanoparticle for treating fibrotic diseases. The present non-clinical study investigated the potential 4-week repeated intravenous dose toxicity and toxicokinetics of SAMiRNA-AREG at dose levels of 0, 25, 50, and 100 mg/kg/day in cynomolgus monkeys. During the test period, mortality, clinical observation, body and organ weights, food consumption, ophthalmology, electrocardiography, hematology, serum chemistry, urinalysis, and gross and microscopic pathology were examined. Serum samples were collected at various time points (0, 0.1, 0.5, 1, 3, 6, 10, 24, and 48 h) after dosing on days 1 and 29 for toxicokinetic analysis. The repeated intravenous dose toxicity study revealed no treatment-related significant changes or serious toxicity compared to the vehicle control group. SAMiRNA-AREG exhibited a non-linear toxicokinetic profile, with the t_1/2 value ranging from 2.97 to 5.88 h in single dosing and from 2.44 to 4.01 h in repeated dosing. In conclusion, the no-observed-adverse-effect level for SAMiRNA-AREG was considered to be ≥ 100 mg/kg/day with C_max and AUC_last values of 650,181.0–764,279.7 μg/mL and 539,728.0–606,033.5 h ng/mL, respectively, on day 29, and no target organs were identified.

Fibrosis is a serious unintended side effect of radiation therapy. In this study, we aimed to investigate whether amphiregulin (AREG) plays a critical role in fibrosis development after total-body irradiation (TBI). We found that the expression of AREG and fibrotic markers, such as α-smooth muscle actin (α-SMA) and collagen type I alpha 1 (COL1α1), was elevated in the kidneys of 6 Gy TBI mice. Expression of AREG and α-SMA was mainly elevated in the proximal and distal tubules of the kidney in response to TBI, which was confirmed by immunofluorescence staining. Knockdown of Areg mRNA using self-assembled-micelle inhibitory RNA (SAMiRNA) significantly reduced the expression of fibrotic markers, including α-SMA and COL1α1, and inflammatory regulators. Finally, intravenous injections of SAMiRNA targeting mouse Areg mRNA (SAMiRNA-mAREG) diminished radiation-induced collagen accumulation in the renal cortex and medulla. Taken together, the results of the present study suggest that blocking of AREG signaling via SAMiRNA-mAREG treatment could be a promising therapeutic approach to alleviate radiation-induced kidney fibrosis.

Androgenetic alopecia (AGA) is the most common type of hair loss in men and women. Dihydrotestosterone (DHT) and androgen receptor (AR) levels are increased in patients with AGA, and DHT-AR signaling correlates strongly with AGA pathogenesis. In this study, treatment with self-assembled micelle inhibitory RNA (SAMiRNA) nanoparticle-type siRNA selectively suppressed AR expression in vitro. Clinical studies with application of SAMiRNA to the scalp and massaging to deliver it to the hair follicle confirmed its efficacy in AGA. For identification of a potent SAMiRNA for AR silencing, 547 SAMiRNA candidates were synthesized and screened. SAMiRNA-AR68 (AR68) was the most potent and could be efficiently delivered to human follicle dermal papilla cells (HFDPCs) and hair follicles, and this treatment decreased the AR mRNA and protein levels. We confirmed that 10 µM AR68 elicits no innate immune response in human PBMCs and no cytotoxicity up to 20 µM with HFDP and HaCaT cells. Clinical studies were performed in a randomized and double-blind manner with two different doses and frequencies. In the low-dose (0.5 mg/ml) clinical study, AR68 was applied three times per week for 24 weeks, and through quantitative analysis using a phototrichogram, we confirmed increases in total hair counts. In the 24-week long high-dose (5 mg/ml) clinical study, AR68 showed average additional hair growth of 1.3-1.9 hairs/cm² per month, which is comparable to finasteride. No side effects were observed. Therefore, SAMiRNA targeting AR mRNA is a potential novel topical treatment for AGA.

The self-assembled-micelle inhibitory RNA-targeting amphiregulin (SAMiRNA-AREG) is a novel small-interfering RNA (siRNA) nanoparticle that is used for treatment of pulmonary fibrosis. We investigated the potential genotoxicity of SAMiRNA-AREG based on the guidelines published by the Organization for Economic Cooperation and Development. In the bacterial reverse mutation assay (Ames test), SAMiRNA-AREG did not induce mutations in Salmonella typhimurium TA100, TA1535, TA98, and TA1537 and Escherichia coli WP2uvrA at concentrations of up to 3000 μg/plate with or without metabolic activation. The SAMiRNA-AREG (concentrations up to 500 μg/mL) did not induce chromosomal aberrations in cultured Chinese hamster lung cells with or without metabolic activation. In the in vivo mouse bone marrow micronucleus assay, the SAMiRNA-AREG (concentrations up to 300 mg/kg body weight) did not affect the proportions of polychromatic erythrocytes and total erythrocytes, nor did it increase the number of micronucleated polychromatic erythrocytes in ICR mice. Collectively, these results suggest that SAMiRNA-AREG is safe with regard to genotoxicity such as mutagenesis or clastogenesis under the present experimental conditions. These results might support the safety of SAMiRNA-AREG as a potential therapeutic agent for pharmaceutical development.