AT-527 is a novel modified guanosine nucleotide prodrug inhibitor of the hepatitis C virus (HCV) NS5B polymerase, with increased in vitro antiviral activity compared to sofosbuvir and a highly differentiated favorable preclinical profile compared to other anti-HCV nucleoside/nucleotide analogs.

Severe coronavirus disease 2019 (COVID-19) is characterised by pneumonia with excessive systemic inflammation, referred to as a “cytokine storm” [1–3]. Dexamethasone treatment decreases mortality in patients with COVID-19 receiving respiratory support and is standard of care for severe COVID-19 [4, 5]. However, pulmonary inflammation, which drives COVID-19 morbidity and mortality [3], can persist despite corticosteroid use [6, 7]. Janus kinase (JAK) inhibition blocks signalling by many cytokines in diverse cell types, offering broad immunomodulation [8]. The oral JAK-1/2 inhibitor baricitinib combined with the antiviral remdesivir shows clinical efficacy in patients with severe COVID-19 [9]. Direct delivery of JAK inhibition to the lung via inhalation could overcome corticosteroid-resistant pulmonary inflammation [10], offering the potential for improved responses while minimising risk of excessive systemic immunosuppression. The novel inhaled pan-JAK inhibitor nezulcitinib (TD-0903) was designed to target all JAK isoforms (JAK1, JAK2, JAK3, TYK2; −log inhibition constant ≥9.2) and optimise delivery to the lungs while limiting systemic exposure (R. Sana and co-workers; unpublished results: abstract submitted to ERS International Congress, 2021). We report results from the completed part 1 of a 2-part phase 2 trial (NCT04402866) in hospitalised patients with severe COVID-19.

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a b s t r a c tMurine antisera with neutralising activity for the coronavirus causative of Middle East respiratory syndrome (MERS) were induced by immunisation of Balb/c mice with the receptor binding domain (RBD) of the viral Spike protein. The murine antisera induced were fully-neutralising in vitro for two separate clinical strains of the MERS coronavirus (MERS-CoV). To test the neutralising capacity of these antisera in vivo, susceptibility to MERS-CoV was induced in naive recipient Balb/c mice by the administration of an adenovirus vector expressing the human DPP4 receptor (Ad5-hDPP4) for MERS-CoV, prior to the passive transfer of the RBD-specific murine antisera to the transduced mice. Subsequent challenge of the recipient transduced mice by the intra-nasal route with a clinical isolate of the MERS-CoV resulted in a significantly reduced viral load in their lungs, compared with transduced mice receiving a negative control antibody. The murine antisera used were derived from mice which had been primed subcutaneously with a recombinant fusion of RBD with a human IgG Fc tag (RBD-Fc), adsorbed to calcium phosphate microcrystals and then boosted by the oral route with the same fusion protein in reverse micelles. The data gained indicate that this dual-route vaccination with novel formulations of the RBD-Fc, induced systemic and mucosal anti-viral immunity with demonstrated in vitro and in vivo neutralisation capacity for clinical strains of MERS-CoV. Crown

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.