Introduction: The phase 3 PROVENT and STORM CHASER studies evaluated AZD7442 (tixagevimab/cilgavimab) for pre-exposure and post-exposure prophylaxis of symptomatic coronavirus disease 2019 (COVID-19). We report the final 15-month results of both studies.
Methods: In PROVENT, participants were randomized 2:1 to receive 300 mg AZD7442 (n = 3460) or placebo (n = 1737). In STORM CHASER, participants were enrolled within 8 days of exposure to a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected individual and randomized 2:1 to receive 300 mg AZD7442 (n = 749) or placebo (n = 372).
Results: In PROVENT, the relative risk reduction (RRR) in symptomatic COVID-19 for AZD7442 versus placebo was 76.7% at primary analysis [95% confidence interval (CI) 46.1, 90.0; p < 0.001], 83.0% at day 183 (95% CI 67.3, 91.2; nominal p < 0.001), and 46.3% at day 366 (95% CI 23.1, 62.4; nominal p < 0.001). Severe/critical COVID-19 was reduced by 91.4% with AZD7442 versus placebo by day 366 (95% CI 61.3, 98.1; nominal p < 0.0001). Adverse events (AEs) occurred in 58.2% and 58.0% of participants administered AZD7442 or placebo, respectively; serious AEs (SAEs) occurred in 6.2% and 5.6%, respectively. In STORM CHASER, the RRR in symptomatic COVID-19 for AZD7442 versus placebo was 33.3% at primary analysis (95% CI - 25.9, 64.7; p = 0.212), 43.3% at day 183 (95% CI 1.4, 67.4; nominal p = 0.044) and 3.4% at day 366 (95% CI - 35.6, 31.2; nominal p = 0.842). Severe/critical COVID-19 did not occur in participants receiving AZD7442 versus 0.5% of participants receiving placebo by day 366. AEs occurred in 46.5% and 51.9% of participants administered AZD7442 or placebo, respectively; SAEs occurred in 2.7% and 4.3%, respectively. In both studies, serum concentration-time profiles over 457 days were similar for tixagevimab and cilgavimab and consistent with the extended half-life reported for AZD7442 (approximately 90 days).
Conclusion: This analysis provides proof of concept supporting long-term safety of intramuscularly administered AZD7442 for prevention of symptomatic/severe COVID-19. A graphical abstract is available with this article.
Gov identifiers: PROVENT (NCT04625725) and STORM CHASER (NCT04625972).
Keywords: COVID-19; Cilgavimab; Clinical trial; Monoclonal antibody; Prophylaxis; Tixagevimab.
Antibodies are proteins produced by the body’s immune system to specifically target foreign substances, such as viruses. AZD7442 is made up of an antibody pair (tixagevimab and cilgavimab) that specifically bind and neutralize severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing coronavirus disease 2019 (COVID-19). AZD7442 was designed to give several months of protection against the virus. These antibodies were tested in two clinical trials to see if they could either protect people from getting COVID-19 (PROVENT trial) or prevent people already exposed to SARS-CoV-2 from getting COVID-19 (STORM CHASER trial). In the two trials, approximately 6000 adults received AZD7442 or placebo (injections that look exactly like AZD7442 but contain no medicine). Protection against COVID-19 was monitored for up to 1 year, and safety for up to 15 months. The percentage of trial participants who reported side effects was similar in the AZD7442 and placebo groups, in both trials. The PROVENT trial showed that AZD7442 reduced the risk of getting COVID-19 up to 6 months and protected against severe COVID-19 for up to 1 year. In STORM CHASER, participants were treated after SARS-CoV-2 exposure but before a positive COVID-19 test. Some participants were already infected with SARS-CoV-2 at the start of the trial, others were not. STORM CHASER showed that AZD7442 protected people against COVID-19 for up to 6 months if they were not already infected at the start. The results of these trials provide proof of concept to support the long-term safety of AZD7442 for the prevention of COVID-19.
© 2024. The Author(s).