A phase 2 study of the inhaled pan-JAK inhibitor TD-0903 in severe COVID-19: Part 1

Background: Lung-targeted anti-inflammatory therapy could potentially improve outcomes in patients with COVID-19. The novel inhaled pan-Janus kinase (JAK) inhibitor TD 0903 was designed to optimise delivery to the lungs while limiting systemic exposure. Here, we report results from the completed Part 1 of a 2-part phase 2 trial (NCT04402866) in hospitalised patients with severe COVID-19. Methods: Part 1 explored 3 doses of TD-0903 (1, 3, and 10 mg once-daily for 7 days) and placebo in a randomised, double-blind, ascending-dose study. Each dose cohort comprised 8 hospitalized patients (6:2 TD-0903:placebo) with PCR-confirmed COVID-19 requiring supplemental oxygen and receiving background standard-of-care therapy. Key objectives included safety and tolerability, pharmacokinetics, and oxygen saturation/fraction of inspired oxygen ratio; clinical outcomes were also explored. Data were summarised as descriptive statistics. Results: Twenty-five patients were randomised to receive TD 0903 1 mg (n = 6), 3 mg (n = 7), 10 mg (n = 6), or placebo (n = 6). Almost all patients (92%) received background dexamethasone; 3 (12%) received remdesivir. TD-0903 was generally well tolerated with no drug-related serious adverse events. Low plasma concentrations of TD-0903 were observed at all doses. Clinically favourable numerical trends in patients receiving TD-0903 vs placebo included improved 8-point clinical status, shortened hospitalisation, improved oxygenation, and fewer deaths. Conclusions: In Part 1 of this phase 2 trial, the novel inhaled JAK inhibitor TD-0903 showed potential for treatment of patients with severe COVID-19. TD-0903 3 mg is being evaluated in Part 2 of the randomised, double-blind, parallel-group trial in 198 hospitalized patients with COVID-19.