Impact of Bebtelovimab Treatment Timing on COVID-19 Outcomes in Ambulatory Solid Organ Transplant Recipients.

Background: Outcomes after bebtelovimab treatment for COVID-19 were favorable for most but not all solid organ transplant recipients (SOTRs) during the era of Omicron BA.2 to BA.5, but effects of timing of bebtelovimab administration on these outcomes are unknown. We sought to compare outcomes of SOTR who received early bebtelovimab ("EBT", given ≤ 2 days from diagnosis) versus late bebtelovimab ("LBT", given between Days 3 and 7), versus no bebtelovimab (NBT).

Methods: This was a retrospective cohort study of SOTRs with mild-to-moderate COVID-19, with endpoint of 30-day COVID-19-related hospitalization. Multivariable logistic regression was performed to determine variables associated with receiving EBT, and to assess impact of EBT on hospitalization. A propensity score (PS) was calculated for EBT versus NBT.

Results: Of 297 SOTRs, 162 (58.1%) received EBT, 46 (16.5%) LBT, and 71 (25.4%) NBT. Early bebtelovimab treatment was associated with a lower risk of 30-day COVID-19-related hospitalization compared to NBT (OR, 0.112 [95% CI, 0.018-0.686]; p = 0.018). There was no significant difference in hospitalization risk between LBT and NBT, suggesting that delayed administration may not confer additional benefits over no treatment.

Conclusions: Early bebtelovimab treatment in outpatient SOTRs was associated with a lower risk of hospitalization compared to no treatment, while late administration did not show a significant advantage over no treatment. Although bebtelovimab is no longer authorized, these findings suggest that the timing of COVID therapies for SOTRs may be important to optimize outcomes.