Timing of REGEN-COV administration and progression to severe COVID-19
Kadowaki et al.,
Timing of REGEN-COV administration and progression to severe COVID-19,
Journal of Infection and Chemotherapy, doi:10.1016/j.jiac.2022.07.002
Retrospective 342 patients in Japan, showing significantly greater efficacy of casirivimab/imdevimab with earlier treatment. The proportion of patients progressing to severe COVID-19 increased daily from symptom onset and increased sharply from day 5.
Efficacy is variant dependent. In Vitro research suggests a lack of efficacy for omicron [Liu, Sheward, Tatham, VanBlargan].
Kadowaki et al., 11 Jul 2022, retrospective, Japan, peer-reviewed, 5 authors, study period 19 July, 2021 - 30 September, 2021.
Contact:
p5j44x0d@s.okayama-u.ac.jp.
Abstract: Journal of Infection and Chemotherapy xxx (xxxx) xxx
Contents lists available at ScienceDirect
Journal of Infection and Chemotherapy
journal homepage: www.elsevier.com/locate/jic
Original Article
Timing of REGEN-COV administration and progression to severe COVID-19
Tomoka Kadowaki a, *, Sato Imajou b, Naomi Matsumoto a, Soshi Takao a, Takashi Yorifuji a
a
b
Department of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
COVID-19 Infection Control Group, Okayama Prefecture Department of Health and Social Welfare, Okayama, Japan
A R T I C L E I N F O
A B S T R A C T
Keywords:
REGEN-COV
COVID-19
Timing of administration
Severe disease
Epidemiology
Introduction: Several clinical trials have demonstrated that REGEN-COV (casirivimab and imdevimab) decreases
the risk of hospitalization and death among COVID-19 patients. However, these trials did not evaluate the
optimal timing of its administration, and evidence is limited regarding the relationship between the timing of
administration and progression to severe COVID-19 among patients who receive REGEN-COV in a real-world
setting. We examined the association between the timing of REGEN-COV administration and progression to
severe COVID-19 among patients who received REGEN-COV in Japan.
Methods: We included a total of 342 COVID-19 patients (37 hospitals) who received REGEN-COV between July
19 and September 30, 2021. We calculated the difference between the date of symptom onset and the date of
administration as an indicator of the timing of REGEN-COV administration and determined progression to severe
COVID-19 after REGEN-COV administration. We conducted a logistic regression analysis, adjusting for potential
confounders.
Results: The proportion of cases progressing to severe COVID-19 increased daily from symptom onset and sharply
increased from day 5 of onset. The early administration (days 0–4) decreased the risk of progression to severity
compared with late administration (after day 5), with an adjusted odds ratio of 0.29 (95% confidence interval:
0.11–0.56).
Conclusions: The early administration of REGEN-COV was associated with a decreased risk of progression to
severe COVID-19 when the delta variant was dominant. The present epidemiological findings indicate that this
monoclonal antibody therapy should be implemented very early in the clinical course probably even for
emerging variants such as omicron BA.2.
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