Nasal mRNA therapy shows promising results in asthma patients hit with rhinovirus

A nasal mRNA shot takes on asthma's viral trigger

Rhinovirus is one of the most common triggers of asthma exacerbations, and a new therapy may finally offer a targeted defense. ETH47, developed by Ethris, is a nasally delivered mRNA drug that instructs cells to produce interferon lambda — a natural antiviral protein — right where it's needed most. In a randomized, placebo-controlled phase 2a trial of 50 adults with symptomatic asthma, a single nasal dose given one day before a controlled rhinovirus challenge showed consistent improvements across multiple outcomes, with no severe adverse events reported.

The results were encouraging across the board: patients on ETH47 had 73% fewer respiratory treatment-emergent adverse events, used rescue medication 65% less often, and were 37% less likely to develop a cold compared to placebo. Notably, patients with higher interferon lambda expression saw even greater benefits.

By the Numbers:

• 40-fold decrease in virus load on day 2 (peak viral replication) with ETH47 vs. placebo
• 58% reduction in lower respiratory symptom score area under the curve
• 56% fewer patients met the mild exacerbation threshold over 3 consecutive days
• 53% reduction in Jackson Cold Score AUC

Why it matters: Virus-triggered asthma flares are a major driver of hospitalizations and poor outcomes. ETH47's ability to locally boost antiviral defenses — without systemic side effects — could be a meaningful advance for asthma and COPD patients. Larger phase 2b field studies in both conditions are already planned.