Aprotinin treatment against SARS‐CoV‐2: A randomized phase III study to evaluate the safety and efficacy of a pan‐protease inhibitor for moderate COVID‐19

Abstract

Background SARS‐CoV‐2 virus requires host proteases to cleave its spike protein to bind to its ACE2 target through a two‐step furin‐mediated entry mechanism. Aprotinin is a broad‐spectrum protease inhibitor that has been employed as antiviral drug for other human respiratory viruses. Also, it has important anti‐inflammatory properties for inhibiting the innate immunity contact system. Methods This was a multicentre, double‐blind, randomized trial performed in four Spanish hospitals comparing standard treatment versus standard treatment + aprotinin for patients with COVID‐19 between 20 May 2020 and 20 October 2021. The primary efficacy outcomes were length of hospital stay and ICU admission. The secondary endpoints were each of the primary efficacy outcomes and a composite of oxygen therapy, analytical parameters and death. Safety outcomes included adverse reactions to treatment during a 30‐day follow‐up period. Treatment was given for 11 days or till discharge. Results With almost identical analytical profiles, significant differences were observed in treatment time, which was 2 days lower in the aprotinin group (p = .002), and length of hospital admission, which was 5 days shorter in the aprotinin group (p = .003). The incidence of discharge was 2.19 times higher (HR: 2.188 [1.182–4.047]) in the aprotinin group than in the placebo group (p = .013). In addition, the aprotinin‐treated group required less oxygen therapy and had no adverse reactions or side effects. Conclusion Inhaled aprotinin may improve standard treatment and clinical outcomes in hospitalized patients with COVID‐19, resulting in a shorter treatment time and hospitalization compared with the placebo group. The administration of aprotinin was safe.

TMPRSS2, a novel host-directed drug target against SARS-CoV-2

“… 4 More encouraging data came from the aprotinin study: aerosolized aprotinin reduced the length of hospital admission and oxygen requirement. 5 Importantly, no adverse reactions were observed. Thus, inhalation could be a safer way to administer protease inhibitors against COVID-19, tailored to reach TMPRSS2 that is expressed on the cell surface of target cells in the airways.…”

Synergism of interferon-beta with antiviral drugs against SARS-CoV-2 variants

“…Effects against BA.2 were less pronounced (IC50: 1.95µM) but still in the range of clinically achievable plasma concentrations after systemic administration, which have been shown to reach 11.8µM 6 . Moreover, aerosol preparations like the one used in the clinical trial that demonstrated therapeutic efficacy of aprotinin against COVID-19 7 are expected to result in substantially higher local aprotinin concentrations in the lungs.…”

Synergism of interferon-beta with antiviral drugs against SARS-CoV-2 variants

“…Previously, we have shown that the protease inhibitor aprotinin inhibits replication of the SARS-CoV-2 original Wuhan strain at least in part by inhibition of the cleavage and activation of the viral spike (S) protein by host cell proteases [Bojkova et al, 2020]. Based on these findings, a clinical trial was initiated that reported improved outcomes of COVID-19 patients treated with an aprotinin aerosol [Redondo-Calvo et al, 2022]. Among other improvements, aprotinin treatment reduced the length of hospital stays by five days [Redondo-Calvo et al, 2022].…”

“…Based on these findings, a clinical trial was initiated that reported improved outcomes of COVID-19 patients treated with an aprotinin aerosol [Redondo-Calvo et al, 2022]. Among other improvements, aprotinin treatment reduced the length of hospital stays by five days [Redondo-Calvo et al, 2022].…”

“…Based on these findings, we here systematically compared the sensitivity of Delta, BA.1, and BA.2 isolates to betaferon (a clinically approved interferon-β preparation) alone or in combination with the approved anti-SARS-CoV-2 drugs remdesivir, molnupiravir, and nirmatrelvir [Ho et al, 2022]. Moreover, we included aprotinin in this study, a protease inhibitor that we have shown to inhibit SARS-CoV-2 replication at least in part by interfering with the cleavage and activation of the viral spike (S) protein by host cell proteases [Bojkova et al, 2020; Bojkova et al, 2022] and that was recently reported to be effective in COVID-19 patients in a clinical trial [Redondo-Calvo et al, 2022].…”