Dynamics of antibody titers to SARS-CoV-2 and clinical outcomes after sotrovimab pre-exposure prophylaxis early after allogeneic hematopoietic stem cell transplantation - Report - MDSpire
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Dynamics of antibody titers to SARS-CoV-2 and clinical outcomes after sotrovimab pre-exposure prophylaxis early after allogeneic hematopoietic stem cell transplantation
Antibody Response and Outcomes After Sotrovimab Prophylaxis Post-AlloHCT
Overview
In alloHCT recipients receiving sotrovimab as COVID-19 pre-exposure prophylaxis within 3 months post-transplant, neutralizing antibody titers against SARS-CoV-2 variants increased significantly, peaking at day 7 and remaining detectable through day 60. Breakthrough infections occurred in 19.4% of patients but were mostly asymptomatic or mild, with minimal adverse events reported.
Background
Allogeneic hematopoietic cell transplantation recipients are at increased risk for severe COVID-19 and have impaired vaccine responses early post-transplant. Vaccination is recommended starting three months after alloHCT, leaving a vulnerable period. Monoclonal antibody pre-exposure prophylaxis, such as sotrovimab, has been used to bridge this gap, especially during the emergence of Omicron variants. However, data on antibody dynamics and clinical outcomes in early post-alloHCT patients receiving sotrovimab are limited.
Data Highlights
Parameter
Timepoint
Findings
Anti-S/RBD total Ig levels
Baseline (Day 0)
Median 1016.5 U/ml; 22.2% had <256 U/ml; 19.4% above upper detection limit
Anti-S/RBD total Ig levels
Day 7 to 60
Increased and stable; 86.1% above upper detection limit
Sotrovimab administration early post-alloHCT significantly increased neutralizing antibody titers against SARS-CoV-2 variants, peaking at day 7.
Neutralizing antibodies against Omicron BA.1 and BA.2 remained detectable in over 90% of patients at day 60.
Prior SARS-CoV-2 vaccination or infection before alloHCT correlated with higher baseline neutralizing activity.
Breakthrough SARS-CoV-2 infections occurred in 19.4% of patients but were mostly asymptomatic or mild.
Sotrovimab was well tolerated with only one mild adverse event reported.
All patients survived through 90 days post-sotrovimab administration.
Clinical Implications
Sotrovimab pre-exposure prophylaxis is a safe and effective strategy to provide early post-alloHCT patients with neutralizing antibodies against SARS-CoV-2, including Omicron variants, during the vulnerable period before vaccination is effective. Monitoring antibody levels and breakthrough infections can guide clinical management. The low incidence of severe COVID-19 supports sotrovimab use as a bridging intervention in this high-risk population.
Conclusion
Sotrovimab administration early after alloHCT induces robust and sustained neutralizing antibody responses with a favorable safety profile, reducing the risk of severe COVID-19 during the critical early post-transplant period. These findings support its role as an effective pre-exposure prophylaxis in alloHCT recipients.
References
University Hospital Basel Study 2022 -- Antibody Response Dynamics to SARS-CoV-2 and Clinical Outcomes Following Sotrovimab Prophylaxis in Early Post-Allogeneic Hematopoietic Stem Cell Transplantation
