Investigating the Effect of Ensitrelvir in Treating Infection with the Omicron Subvariants of SARS-CoV-2
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Reviewed & Translated by Dat Tien Nguyen, B.A, ScM.
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Posted on June 28th, 2024
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Most of the current clinical guidelines recommend the usage of remdesivir, molnupiravir, or the combination of ritonavir and nirmatrelvir to manage severe SARS-CoV-2 infection. However, studies that proved the effectiveness of these antivirals were conducted before Omicron subvariants became dominant. With the concern that the Omicron subvariants contains mutation that would negate the effect of current recommended treatment, a study was conducted to assess the effectiveness of ensitrelvir - a protease inhibitor that had proven to be effective against Omicron in animal studies.
The phase 3 clinical trial involved 1,821 patients from Vietnam, Japan, and South Korea who tested positive for SARS-CoV-2 within 5 days prior to enrollment. Over 90% of participants had received at least two vaccine doses, with about half having received a third dose. Nearly two-thirds were infected with the BA.2/21L Omicron subvariant, while around 20% had the BA.1/21K Omicron variant. At baseline, the average SARS-CoV-2 RNA level was approximately 1 log10 copies/mL. Participants were randomly assigned to receive either a placebo or one of two doses of ensitrelvir orally: 125 mg with an initial dose of 375 mg, or 250 mg with an initial dose of 750 mg. After 5 days of treatment, researchers concluded that both ensitrelvir doses significantly reduced SARS-CoV-2 RNA levels and accelerated clinical recovery and symptom resolution by one day. Adverse event records indicated that ensitrelvir use was associated with a decrease in high-density lipoprotein levels. Future studies should compare the efficacy of ensitrelvir with currently approved SARS-CoV-2 antivirals, considering the financial costs and storage requirements of different treatments.
The phase 3 clinical trial involved 1,821 patients from Vietnam, Japan, and South Korea who tested positive for SARS-CoV-2 within 5 days prior to enrollment. Over 90% of participants had received at least two vaccine doses, with about half having received a third dose. Nearly two-thirds were infected with the BA.2/21L Omicron subvariant, while around 20% had the BA.1/21K Omicron variant. At baseline, the average SARS-CoV-2 RNA level was approximately 1 log10 copies/mL. Participants were randomly assigned to receive either a placebo or one of two doses of ensitrelvir orally: 125 mg with an initial dose of 375 mg, or 250 mg with an initial dose of 750 mg. After 5 days of treatment, researchers concluded that both ensitrelvir doses significantly reduced SARS-CoV-2 RNA levels and accelerated clinical recovery and symptom resolution by one day. Adverse event records indicated that ensitrelvir use was associated with a decrease in high-density lipoprotein levels. Future studies should compare the efficacy of ensitrelvir with currently approved SARS-CoV-2 antivirals, considering the financial costs and storage requirements of different treatments.