Complement blockade with eculizumab for treatment of severe Coronavirus Disease 2019 in pregnancy: A case series.

PROBLEM: We evaluated eculizumab, a complement protein C5 inhibitor, for treatment of severe COVID-19 in pregnant and postpartum individuals. METHOD OF STUDY: Protocol ECU-COV-401 (clinicaltrials.gov NCT04355494) is an open label, multicenter, Expanded Access Program (EAP), evaluating eculizumab for treatment of severe COVID-19. Participants enrolled at our center from August 2020 to February 2021. Hospitalized patients were eligible if they had severe COVID-19 with bilateral pulmonary infiltrates and oxygen requirement. Eculizumab was administered on day 1 (1200 mg IV) with additional doses if still hospitalized (1200 mg IV on Days 4 and 8; 900 mg IV on Days 15 and 22; optional doses on Days 12 and 18). The primary outcome was survival at Day 15. Secondary outcomes included survival at Day 29, need for mechanical ventilation, and duration of hospital stay. We evaluated pharmacokinetic and pharmacodynamic data, safety, and adverse outcomes. RESULTS: Eight participants were enrolled at the Cedars-Sinai Medical Center, six during pregnancy (mean 30 ± 4.0 weeks) and two in the postpartum period. Baseline oxygen requirement ranged from 2 L/min nasal cannula to 12 L/min by non-rebreather mask. The median number of doses of eculizumab was 2 (range 1-3); the median time to hospital discharge was 5.5 days (range 3-12). All participants met the primary outcome of survival at Day 15, and all were alive and free of mechanical ventilation at Day 29. In three participants we demonstrated that free C5 and soluble C5b-9 levels decreased following treatment. There were no serious adverse maternal or neonatal events attributed to eculizumab at 3 months. CONCLUSION: We describe use of eculizumab to treat severe COVID-19 in a small series of pregnant and postpartum adults. A larger, controlled study in pregnancy is indicated.

Pharmacokinetic and Pharmacodynamic Evaluation of Ravulizumab in Adults with Severe Coronavirus Disease 2019.

INTRODUCTION: Terminal complement amplification is hypothesized to be a key contributor to the clinical manifestations of severe coronavirus disease 2019 (COVID-19). Ravulizumab, a humanized monoclonal antibody that binds with high affinity to complement protein C5 and inhibits terminal complement activation, is being evaluated as a treatment for COVID-19-related severe pneumonia, acute lung injury, and acute respiratory distress syndrome in an ongoing phase 3 randomized controlled trial (ALXN1210-COV-305). To address the overactivation of terminal complement in severe COVID-19 compared to the diseases in which ravulizumab is currently approved, a modified dosing regimen was adopted. This analysis evaluates preliminary pharmacokinetic/pharmacodynamic data to confirm the modified dosing regimen. METHODS: Weight-based ravulizumab doses were administered on days 1, 5, 10, and 15. Serum levels of ravulizumab and free C5 were measured before and after administration of ravulizumab and any time on day 22. Free C5 levels < 0.5 µg/mL indicate complete C5 inhibition. The pharmacokinetic target was defined as ravulizumab concentrations at the end of the dosing interval > 175 µg/mL, the concentration above which C5 is completely inhibited. RESULTS: Twenty-two patients were included in this evaluation. At baseline, mean C5 concentration was 240 ± 67 µg/mL. In all patients and at all individual timepoints after the first dose was administered, ravulizumab concentrations remained > 175 µg/mL and free C5 concentrations remained < 0.5 µg/mL. CONCLUSION: High levels of baseline C5 observed in patients with severe COVID-19 contribute to the growing body of evidence that suggests this disease is marked by amplification of terminal complement activation. Data from this preliminary pharmacokinetic/pharmacodynamic evaluation of 22 patients with severe COVID-19 show that the modified ravulizumab dosing regimen achieved immediate and complete terminal complement inhibition, which can be sustained for up to 22 days. These data support the continued use of this dosage regimen in the ongoing phase 3 study. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT04369469.

While many people have no or mild COVID-19 symptoms, a small number of people become very sick and require hospitalization in intensive care units. One part of their immune system, known as complement, overreacts and attacks the lungs and other organs. Researchers are looking for a way to keep the immune system from attacking the body instead of protecting it. Ravulizumab is a medication currently used to do this in other diseases. Ravulizumab is being studied to see if it can reduce the destructive and deadly effects of the coronavirus infection. In this evaluation, ravulizumab effectively reduced complement in patients with severe COVID-19.