Temesgem, Zelalem

Abstract Background Severe coronavirus disease 2019 (COVID-19) often results from the immune-mediated cytokine storm, triggered by granulocyte macrophage-colony stimulating factor (GM-CSF), potentially leading to respiratory failure and death. Lenzilumab, a novel anti-human GM-CSF monoclonal antibody, neutralizes GM-CSF and demonstrated potential to improve clinical outcomes in a matched case-cohort study of patients with severe COVID-19 pneumonia. This Phase 3 randomized, double-blind, placebo-controlled trial investigated the efficacy and safety of lenzilumab to improve the likelihood of survival without invasive mechanical ventilation (SWOV), beyond available treatments. Methods Hypoxic patients, hospitalized with COVID-19 (n=520), requiring supplemental oxygen, but not invasive mechanical ventilation, were randomized on Day 0 to receive lenzilumab (1800mg, n=261) or placebo (n=259), and available treatments, including remdesivir and/or corticosteroids; and were followed through Day 28. Results Baseline demographics were comparable between groups: male, 64.7%; mean age, 60.5 years; median CRP, 79.0 mg/L. Patients across both groups received steroids (93.7%), remdesivir (72.4%), or both (69.1%). Lenzilumab improved the primary endpoint, likelihood of SWOV in the mITT population, by 1.54-fold (HR: 1.54; 95%CI: 1.02-2.32, p=0.0403). Lenzilumab improved SWOV by 1.91-fold (nominal p=0.0073) and 1.92-fold (nominal p=0.0067) in patients receiving remdesivir or remdesivir and corticosteroids, respectively. A key secondary endpoint of incidence of IMV, ECMO or death was also improved in patients receiving remdesivir (p=0.020) or remdesivir and corticosteroids (p=0.0180). Treatment-emergent serious adverse events were similar across both groups. Conclusion Lenzilumab significantly improved SWOV in hypoxic COVID-19 patients upon hospitalization, with the greatest benefit observed in patients receiving treatment with remdesivir and corticosteroids. NCT04351152 Disclosures Zelalem Temesgem, MD, Humanigen, Inc (Grant/Research Support) Jason Baker, MD, Humanigen, Inc (Grant/Research Support) Christopher Polk, MD, Atea (Research Grant or Support)Gilead (Advisor or Review Panel member, Research Grant or Support)Humanigen (Research Grant or Support)Regeneron (Research Grant or Support) Claudia R. Libertin, MD, Gilead (Grant/Research Support) Colleen F. Kelley, MD, MPH, Gilead Sciences (Individual(s) Involved: Self): Grant/Research Support; Moderna (Individual(s) Involved: Self): Grant/Research Support; Novavax (Individual(s) Involved: Self): Grant/Research Support; Viiv (Individual(s) Involved: Self): Grant/Research Support Vincent Marconi, MD, Bayer (Consultant, Scientific Research Study Investigator)Eli Lilly (Consultant, Scientific Research Study Investigator)Gilead Sciences (Consultant, Scientific Research Study Investigator)ViiV (Consultant, Scientific Research Study Investigator) Victoria Catterson, PhD, Humanigen, Inc (Consultant) William Aronstein, MD, PhD, Humanigen, Inc (Consultant) Cameron Durrant, MD, Humanigen, Inc (Employee) Dale Chappell, MD, Humanigen, Inc (Employee) Omar Ahmed, PharmD, Humanigen, Inc (Employee) Gabrielle Chappell, MSc, Humanigen, Inc (Consultant) Andrew Badley, M.D., AbbVie (Consultant) for the LIVE-AIR Study Group, n/a, Humanigen, Inc (Grant/Research Support)

Abstract Background CDI is an important cause of morbidity and mortality in SOT and HCT patients (pts). In retrospective single-center analyses, severe disease and relapse were common. We undertook a multicenter prospective observational study to evaluate outcomes of CDI among both SOT and HCT patients. Methods Adults with a first episode of CDI, defined as 3 liquid stools/24 h with the detection of C. difficile toxin in stool, within the first 2 years of SOT or HCT were recruited from 12 centers internationally in the INSIGHT network. At enrollment, demographics, comorbidities, medication histories and outcomes were collected prospectively over 90 days to assess clinical cure, recurrences and complications and to define baseline risk factors for clinical cure and recurrent CDI. Results 132 patients (81 SOT, 51 HCT (32 allogeneic)) were enrolled: median age 56 years, 62.1% were males, 97% were hospitalized. 80.3% were diagnosed by DNA assay. CDI occurred a median of 20 days post transplant (IQR: 6–133). 108 patients were on PPIs. 98.5% were on antibiotics before CDI. 1st line treatment regimen was oral vancomycin in 66 patients (40 SOT, 26 HCT), metronidazole in 48 patients (27 SOT, 21 HCT), both drugs in 14 (10 SOT, 4 HCT), fidaxomicin (3) and linezolid (1). Rejection within 60 days before CDI was uncommon (6.2% SOT) as was GVHD (27.5%). 110 patients (83%, 95% CI: 46–89)) (65 SOT, 45 HCT) had clinical cure; 18% (95% CI: 11–27) had recurrent CDI, 2 were admitted to the ICU due to CDI, 11 (8.3%) died (2 HCT related to CDI). Among baselines variables, only first-line regimen was associated with a higher rate of clinical cure (P = 0.003), most notably for SOT. Factors that did not have a statistically significant negative impact on clinical cure included sex, age > 60, race, country, transplant type, steroids, diabetes, CMV viremia/disease, WBC > 15,000, creatinine > 1.5 mg/dL, or specific antibiotic given prior to CDI. Higher recurrence rates were associated with metronidazole-only regimen (OR: 4.6, 95% CI: 1.6–12.8; P = 0.004) and a history of CMV after transplant (OR: 5.2, 95% CI: 1.7–15.7; P = 0.003). Conclusion Despite their immunosuppressed state, recurrence, ICU admission and mortality occurred in a minority of SOT and HCT with CDI. Initial use of metronidazole and CMV viremia/disease were associated with higher recurrence rates. Disclosures All authors: No reported disclosures.