LEIDEN, Netherlands — September 9, 2026
Leyden Laboratories B.V. announced positive Phase 1 results for RIG-101, supporting advancement of the investigational intranasal innate immune modulator into Phase 2 development for the prevention of virus-triggered asthma exacerbations. The completed study evaluated RIG-101 in healthy volunteers and patients with asthma and showed that the therapy was safe and well tolerated across all tested dose levels, including up to seven days of daily intranasal administration. Biomarker analyses also demonstrated activation of the intended antiviral response in the upper respiratory tract, including induction of type I and type III interferons and interferon-stimulating genes. The results provide an important clinical development milestone for Leyden Labs following its acquisition of RIGImmune earlier in 2026, which brought RIG-101 and the proprietary NEED™ intranasal delivery platform into the company’s portfolio.
RIG-101 Activates Innate Antiviral Defenses in the Airway
RIG-101 is designed to strengthen the body’s natural antiviral defenses directly at the respiratory mucosa, offering a mechanism distinct from conventional systemic antiviral approaches. The candidate acts on RIG-I, a central mediator of innate immune signaling, with the goal of increasing interferon responses and reducing viral infection. According to Leyden Labs, RIG-101 has demonstrated pan-viral activity and is initially being developed for asthma patients because respiratory viral infections trigger more than 80% of severe asthma exacerbations. The Phase 1 biomarker findings are particularly important because they provide evidence that intranasal administration can activate the biological pathway targeted by the therapy in the upper respiratory tract. By enhancing innate immunity at the site where respiratory viruses enter the body, Leyden Labs believes RIG-101 could provide broad protection against multiple respiratory viruses rather than targeting a single viral strain.
Phase 2 Development to Include Rhinovirus Challenge Study
Leyden Labs plans to advance RIG-101 into a Phase 2 clinical program, with the next planned study being a human rhinovirus challenge study in patients with asthma. The Phase 1 safety and biomarker profile provides the clinical foundation for testing whether activation of the innate antiviral response can translate into meaningful protection against respiratory viral consequences in vulnerable patients. The company’s development strategy is focused on patient populations whose natural antiviral defenses may be impaired and who consequently face increased risks from respiratory infections. The planned challenge study will provide an opportunity to evaluate RIG-101 under controlled viral exposure conditions while further characterizing its potential to prevent virus-driven disease. Advancement into patient-focused Phase 2 research represents a key step in determining whether the mechanism demonstrated in Phase 1 can support a clinically meaningful preventive therapy for asthma and potentially other chronic airway diseases.
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Leyden Labs Expands Mucosal Protection Pipeline
The advancement of RIG-101 strengthens Leyden Labs’ broader mucosal protection strategy, following the company’s acquisition of RIGImmune earlier this year. The transaction added both RIG-101 and the proprietary NEED™ (Nano-Emulsion Effective Delivery) intranasal platform, complementing Leyden Labs’ existing portfolio of broadly protective intranasal antibodies. The company is pursuing an airway-targeted approach based on the premise that respiratory viruses enter primarily through the nose and mouth, creating an opportunity to intervene directly at the gate of entry. Its pipeline includes approaches targeting influenza, coronavirus, rhinovirus and other respiratory viruses, with broadly protective molecules designed to remain useful as viruses mutate. By combining innate immune modulation with broadly protective intranasal antibodies, Leyden Labs is building a diversified mucosal protection platform aimed at vulnerable populations and multiple respiratory viral threats. The positive RIG-101 Phase 1 results now provide clinical momentum for this strategy and support the company’s transition toward broader patient studies.
Source: Leyden Labs ,press release
