Clinical efficacy of baloxavir marboxil versus oseltamivir in kidney transplant recipients with influenza

Kidney transplant recipients (KTRs) are at high risk for severe influenza and its complications. The effectiveness of baloxavir marboxil (hereafter baloxavir) in infected KTRs is still unknown. In this multicenter retrospective study conducted at eight Grade IIIA hospitals in China, KTRs diagnosed with influenza between October 2023 and March 2024 were enrolled. Of the 246 patients assessed, 117 met the inclusion criteria. There were 59 patients who received baloxavir and 58 patients who received oseltamivir. Patients receiving baloxavir had a longer time from symptom onset to treatment (≤48 h, 59.3% versus 79.3%; <i>P</i> = 0.019). Nevertheless, in comparison with those who were administered oseltamivir, they exhibited no statistically significant difference in time to alleviation of influenza symptoms [4 (2-6) versus 5 (3-7); <i>P</i> = 0.054], duration of fever [3 (2-4) versus 3 (2-4); <i>P</i> = 0.347], or viral clearance [6 (40.0%) versus 10 (58.8%); <i>P</i> = 0.479]. However, among patients who received antivirals within 48 h, baloxavir showed a significant correlation with fever resolution when compared with oseltamivir [2 (2, 3) versus 3 (2-4); <i>P</i> = 0.030]. Meanwhile, among patients who received antivirals after 48 h, a remarkable improvement of symptom alleviation in 5 days was observed in the baloxavir-treated group as compared to the oseltamivir-treated group [18 (75.0%) versus 2 (16.7%); <i>P</i> = 0.001]. In conclusion, compared to oseltamivir, patients may derive benefits from baloxavir treatment within 48 h, but especially after 48 h from symptom onset.IMPORTANCEThe multicenter cohort study is the first to compare the clinical efficacy of baloxavir with oseltamivir in influenza kidney transplant recipients (KTRs). The results showed that there were fewer influenza symptoms but a longer time for viral shedding in KTRs compared to non-immunosuppressed patients. No significant difference regarding time to alleviation of influenza symptoms and fever resolution between baloxavir and oseltamivir was found, which is consistent with CAPSTONE-1, whereas influenza KTRs who received baloxavir could have a shorter fever duration and symptom alleviation in 5 days compared to the oseltamivir-treated group. Our findings may provide guidance for influenza therapy in KTRs, solid organ transplant recipients, and immunocompromised patients.