Nasal spray of an IgM‐like ACE2 fusion protein HH‐120 prevents SARS‐CoV‐2 infection: Two investigator‐initiated postexposure prophylaxis trials

Abstract

HH‐120, an IgM‐like angiotensin converting enzyme 2 (ACE2) fusion protein, has been developed as a nasal spray against Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and is currently undergoing human trials. HH‐120 nasal spray was assessed for postexposure prophylaxis (PEP) in two investigator‐initiated (NS01 and NS02) trials with different risk levels of SARS‐CoV‐2 exposure. NS01 enrolled family caregiver participants who had continuous contacts with laboratory‐confirmed index cases; NS02 enrolled participants who had general contacts (Part 1) or close contacts (Part 2) with index cases. The primary endpoints were safety and laboratory‐confirmed and/or symptomatic SARS‐CoV‐2 infection. In NS01 trial (14 participants), the SARS‐CoV‐2 infection rates were 25% in the HH‐120 group and 83.3% in the external control group (relative risk reduction [RRR]: 70.0%). In NS02‐Part 1 (193 participants), the infection rates were 4% (HH‐120) versus 11.3% (placebo), symptomatic infection rates were 0.8% versus 3.5%, hence with a RRR of 64.6% and 77.1%, respectively. In Part 2 (76 participants), the infection rates were 17.1% (HH‐120) versus 30.4% (placebo), symptomatic infection rates were 7.5% versus 27.3%, with a RRR of 43.8% and 72.5%, respectively. No HH‐120‐related serious adverse effects were observed. The HH‐120 nasal spray used as PEP was safe and effective in preventing laboratory‐confirmed and symptomatic SARS‐CoV‐2 infection.