SFX-01 in hospitalised patients with community-acquired pneumonia during the COVID-19 pandemic: a double-blind, randomised, placebo-controlled trial

Abstract

Introduction: Sulforaphane can induce the transcription factor, Nrf2, promoting antioxidant and anti-inflammatory responses. In this study, hospitalised patients with community-acquired pneumonia (CAP) were treated with stabilised synthetic sulforaphane (SFX-01) to evaluate impact on clinical status and inflammation.

Methods: Double-blind, randomised, placebo-controlled trial of SFX-01 (300 mg oral capsule, once daily for 14 days) conducted in Dundee, UK, between November 2020 and May 2021. Patients had radiologically confirmed CAP and CURB-65 (confusion, urea >7 mmol·L^-1, respiratory rate ≥30 breaths·min^-1, blood pressure <90 mmHg (systolic) or ≤60 mmHg (diastolic), age ≥65 years) score ≥1. The primary outcome was the seven-point World Health Organization clinical status scale at day 15. Secondary outcomes included time to clinical improvement, length of stay and mortality. Effects on Nrf2 activity and inflammation were evaluated on days 1, 8 and 15 by measurement of 45 serum cytokines and mRNA sequencing of peripheral blood leukocytes.

Results: The trial was terminated prematurely due to futility with 133 patients enrolled. 65 patients were randomised to SFX-01 treatment and 68 patients to placebo. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was the cause of CAP in 103 (77%) cases. SFX-01 treatment did not improve clinical status at day 15 (adjusted OR 0.87, 95% CI 0.41-1.83; p=0.71), time to clinical improvement (adjusted hazard ratio (aHR) 1.02, 95% CI 0.70-1.49), length of stay (aHR 0.84, 95% CI 0.56-1.26) or 28-day mortality (aHR 1.45, 95% CI 0.67-3.16). The expression of Nrf2 targets and pro-inflammatory genes, including interleukin (IL)-6, IL-1β and tumour necrosis factor-α, was not significantly changed by SFX-01 treatment. At days 8 and 15, respectively, 310 and 42 significant differentially expressed genes were identified between groups (false discovery rate adjusted p<0.05, log₂FC >1).

Conclusion: SFX-01 treatment did not improve clinical status or modulate key Nrf2 targets in patients with CAP primarily due to SARS-CoV-2 infection.

FIGURE 1

Consolidated Standards of Reporting Trials diagram detailing flow of participants in STAR-COVID-19 (SFX-01 Treatment for Acute Respiratory Infections). ^#: one participant in the placebo group withdrew from the study and day 15 status was unknown.

FIGURE 2

Serum cytokine levels and effects of 1-isothiocyanato-4-methyl-sulfinylbutane (SFX-01) treatment. At days 1, 8 and 15, serum was obtained from participants and 45 inflammation-associated cytokines measured. Established Nrf2 targets, a) tumour necrosis factor (TNF)-α, b) interleukin (IL)-1β and c) IL-6 were not significantly affected by SFX-01 treatment compared with levels in the placebo group. Of the 45 cytokines measured, only the epidermal growth factor family member d) transforming growth factor (TGF)-α was significantly higher by day 15 in the SFX-01 group than in the placebo group, and only the apoptosis-inducer e) lymphotoxin-α (LTA) was significantly reduced in the SFX-01 group. Data were analysed by a mixed-model repeated measures approach; data represent model-derived mean±se. Day 1: SFX-01 n=61, placebo n=63; day 8: SFX-01 n=17, placebo n=21; day 15: SFX-01 n=33, placebo n=38.

FIGURE 3

Peripheral blood leukocyte gene expression and effects of 1-isothiocyanato-4-methyl-sulfinylbutane (SFX-01) treatment and comparison with in vitro sulforaphane treatment. At a) day 1, b) day 8 and c) day 15, peripheral blood leukocyte gene expression analysed by mRNA sequencing was compared between SFX-01- and placebo-treated individuals who completed 14 days of trial treatment and had not discontinued drug at the relevant sampling time point. a) Eight significantly differentially expressed genes (DEGs) were identified between the SFX-01 and placebo groups at day 1; b) 310 DEGs were identified at day 8; and c) 42 at day 15. Higher (red) and lower (blue) gene expression levels in the SFX-01 are shown. d–f) The top 10 significant DEGs (adjusted p-value (p_adj) <0.05 and log₂ fold change (FC) >1 or <−1) between SFX-01- and placebo-treated individuals. Red indicates higher expression in the SFX-01 group compared with the placebo group; blue indicates lower expression. Data were analysed using the Wald test and Benjamini–Hochberg procedure. g, h) Transcript per million (TPM) values representing relative expression levels of genes of interest: IL-1β and TNFα at day 15. Day 1: SFX-01 n=59, placebo n=59; day 8: SFX-01 n=14, placebo n=18; day 15: SFX-01 n=30, placebo n=34. i) Re-analysis of a published dataset (GSE160353); differential gene expression analysis of isolated human peripheral blood mononuclear cells (PBMCs) treated with l-sulforaphane (l-SFN) (15 µM) or vehicle for 24 h and processed for RNA sequencing (n=4 individuals), 1032 significant DEGs identified (false discovery rate-adjusted p-value <0.05 and log₂ fold change >1 or <−1).