Nocion Therapeutics has completed patient enrolment in its Phase IIb ASPIRE study assessing taplucainium as a treatment for refractory or unexplained chronic cough (rCC/uCC).

The double-blind, placebo-controlled, randomised trial has enrolled 240 adult patients at over 100 sites across the EU, the UK, Canada, and the US.

It will evaluate the safety, tolerability, and efficacy of taplucainium inhalation powder for one month. Patients have been randomised to receive taplucainium at doses of 1mg, 3mg, 6mg, or placebo.

The primary endpoint of the trial is the change in 24-hour cough frequency from baseline to the end of treatment, as assessed by VitaloJAK Cough Counts.

Secondary endpoints include changes in awake cough count, cough severity, and urge to cough.

Chronic cough is defined as a cough lasting longer than eight weeks, contributing to significant physical, social, and psychosocial impact.

Taplucainium is an inhaled molecule from the class of charged sodium channel blockers (CSCBs), intended to selectively silence activated or inflamed nociceptors with minimal local or systemic side effects.

In contrast to other investigational cough treatments such as P2X purinoceptor 3 (P2X3) antagonists, it is designed for broader activity by entering airway nociceptors through open large pore channels and inhibiting sodium channels that trigger chronic cough.

Nocion Therapeutics chief medical officer Matthew Frankel said: “Fully enrolling the Phase IIb ASPIRE trial represents a major milestone on the path to delivering a transformative new therapy for patients with chronic cough. Taplucainium’s differentiated mechanism has the potential to deliver fast-acting and long-lasting relief by addressing the underlying drivers of chronic cough.

“The rapid pace of enrolment underscores the strong demand among clinicians and patients for a safe and effective treatment for this undertreated, debilitating condition. With the Phase IIb trial now fully enrolled, we are on track to report topline data in Q3 2026 to support a potential registrational programme for taplucainium.”