Single injection of Tixagevimab-cilgavimab halts progression of COVID-19 infection among unvaccinated

UK: In a new study conducted by Hugh Montgomery and team, it was shown that in unvaccinated persons, a single intramuscular tixagevimab-cilgavimab dosage offered statistically and clinically significant protection against progression to severe COVID-19. The findings of this study were published in The Lancet Respiratory Medicine.

"Treatment of mild to moderate COVID-19 with tixagevimab–cilgavimab earlier in the disease course might lead to more favorable outcomes," the researchers wrote in their study. 

Early intramuscular treatment of tixagevimab–cilgavimab, a SARS-CoV-2-neutralizing monoclonal antibody combination, to non-hospitalized persons with mild to severe COVID-19 has the potential to halt disease development. As a result, the purpose of this trial was to assess the safety and effectiveness of tixagevimab–cilgavimab in avoiding progression to severe COVID-19 or death.

TACKLE is a phase 3 double-blind, randomized, placebo-controlled trial that is now being carried out at 95 locations in the United States, Latin America, Europe, and Japan. Participants who had a laboratory-confirmed SARS-CoV-2 infection (proven by RT-PCR or an antigen test) from any respiratory tract material obtained 3 days or fewer before enrolment and had not received a COVID-19 immunization were eligible.

Participants were randomly randomized (1:1) to receive either a single 600 mg dosage of tixagevimab–cilgavimab or a placebo. The randomization was stratified by time since symptom start and the likelihood of progression to severe COVID-19. Through day 29, the key outcomes were severe COVID-19 or death from any cause, as well as safety.

The key findings of this study were as follows:

1. 1014 individuals were enrolled between January 28, 2021, and July 22, 2021, with 910 randomly allocated to a therapy group.

2. The participants' average age was 461 years. Severe COVID-19 or mortality occurred in 18 (4%) of 407 tixagevimab–cilgavimab group individuals vs 37 (9%) of 415 placebo group participants.

3. The absolute danger was reduced by 45%. Adverse events occurred in 132 (29%) of 452 tixagevimab–cilgavimab individuals and 163 (36%) of 451 placebo participants, and were usually mild or moderate in severity.

4. The tixagevimab–cilgavimab group had three COVID-19-reported fatalities, while the placebo group had six.

In conclusion, treatment of mild to moderate COVID-19 with tixagevimab–cilgavimab early in the illness course may result in better results.

Reference: 

Montgomery, H., Hobbs, F. D. R., Padilla, F., Arbetter, D., Templeton, A., Seegobin, S., Kim, K., Campos, J. A. S., Arends, R. H., Brodek, B. H., Alagappan, V., Pangalos, M. N., … Yamamoto, K. (2022). Efficacy and safety of intramuscular administration of tixagevimab–cilgavimab for early outpatient treatment of COVID-19 (TACKLE): a phase 3, randomised, double-blind, placebo-controlled trial. In The Lancet Respiratory Medicine. Elsevier BV. https://doi.org/10.1016/s2213-2600(22)00180-1