Baker, Jason V.

Abstract Background Coronavirus disease 2019 (COVID-19) results from SARS-CoV-2-induced hyperinflammatory immune response, orchestrated by granulocyte-macrophage colony-stimulating factor (GM-CSF). GM-CSF increases interleukin-6 (IL-6) levels, ultimately leading to increased C-reactive protein (CRP). The LIVE-AIR trial demonstrated that lenzilumab, the GM-CSF neutralizing antibody, improved the likelihood of survival without invasive mechanical ventilation (IMV) in hospitalized COVID-19 patients requiring supplemental oxygen but not IMV. This sub-analysis correlated levels of cytokines before and after lenzilumab treatment. Methods LIVE-AIR was a phase 3, randomized, double-blind, placebo-controlled trial (NCT04351152). Patients hospitalized with COVID-19 pneumonia, requiring only supplemental oxygen, were randomized to receive lenzilumab (1800 mg in three equally divided doses of 600 mg, q8h) or placebo IV infusion, in addition to standard of care which included remdesivir and corticosteroids. Blood taken at baseline (BL) and subsequent to treatment through day 10 (D10) were obtained and analyzed by high sensitivity enzyme immunoassay for GM-CSF, IL-6, and CRP. Results Baseline IL-6 levels (Loge-transformed for all cytokines and biomarkers) were linearly correlated with higher baseline GM-CSF levels (slope=0.60, p< 0.001). Baseline CRP levels were linearly correlated with higher baseline IL-6 levels (slope=0.29, p < 0.001). GM-CSF levels decreased with lenzilumab treatment on day 1 (D1) which persisted through D10 (Table). In contrast, GM-CSF increased with placebo treatment. IL-6 levels decreased only with lenzilumab treatment. CRP following lenzilumab or placebo treatment decreased on D1 to similar levels and further decreased on D10 only with lenzilumab treatment. Cytokine Levels Associated with Lenzilumab Treatment Conclusion Lenzilumab decreased GM-CSF as well as downstream cytokines and systemic biomarkers of inflammation during the hyperinflammatory immune response of COVD-19. Disclosures Dale Chappell, MD, MBA, Humanigen, Inc: Employee|Humanigen, Inc: Ownership Interest Adrian Kilcoyne, MD, Humanigen, Inc: Employee Frank Cerasoli, PhD, Humanigen, Inc: Advisor/Consultant John Lukas, PhD, Humanigen, Inc: Advisor/Consultant Cameron Durrant, MD, Humanigen, Inc: Employee|Humanigen, Inc: Ownership Interest Zelalem Temesgen, MD, Gilead: unrestricted educational grant (to the institution)|Humanigen, Inc: Grant/Research Support|Merck: unrestricted educational grant (to the institution)|ViiV: Advisor/Consultant Christopher Polk, MD, Gilead: Advisor/Consultant Jason Baker, MD, Gilead: Grant/Research Support|Humanigen, Inc: Grant/Research Support Vincent Marconi, MD, Gilead: Grant/Research Support.

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)

HIV is an independent risk factor for lung disease, including chronic obstructive pulmonary disease (COPD) and emphysema. Angiotensin receptor blockers may be beneficial in COPD and emphysema through pathways that have been implicated in HIV-related lung disease. We performed a randomized comparison of the effects of losartan versus placebo on the plasma concentrations of the pneumoproteins, surfactant protein D (SPD) and club cell secretory protein (CCSP), in people living with HIV (PLWH). A total of 108 PLWH were included (52 assigned to losartan and 56 assigned to placebo). We found no difference in the change from baseline in log 2 concentrations of CCSP or SPD over 1 year of follow-up. For SPD, we found a strong interaction by CD4+ counts, where those with CD4+ counts >350 cells/mm 3 treated with losartan had more reduction (improvement) in SPD concentration than those treated with placebo ( p value for interaction <.001). In conclusion, we did not find a beneficial effect of losartan on pneumoprotein concentrations in PLWH, but PLWH with higher CD4+ counts may have improvement in SPD when treated with losartan.

Background: Persistent inflammation and incomplete immune recovery among persons with HIV (PHIV) are associated with increased disease risk. We hypothesized that the angiotensin receptor blocker (ARB) losartan would reduce inflammation by mitigating nuclear factor (NF)κB responses and promote T-cell recovery via inhibition of transforming growth factor-beta (TGFβ)-mediated fibrosis. Methods: Losartan (100 mg) versus placebo over 12 months was investigated in a randomized (1 : 1) placebo-controlled trial, among PHIV age at least 50 years, receiving antiretroviral therapy (ART), with HIV RNA less than 200 copies/ml and CD4+ cell count 600 cells/μl or less. Inflammation, fibrosis and myocardial biomarkers were measured in blood using ELISA, electrochemiluminescence and immunoturbidimetric methods, and T-cell and monocyte phenotypes were assessed with flow cytometry among a subset of participants. Changes over follow-up in (log-2 transformed) biomarkers and cell phenotypes (untransformed) were compared between losartan and placebo arms using linear mixed models. Results: Among 108 PHIV (n = 52 to losartan; n = 56 to placebo), 97% had a month 12 visit. Median age was 57 years and baseline CD4+ cell count was 408 cells/μl. Losartan treatment was not associated with an improvement in interleukin-6 levels, or other blood measures of inflammation, immune activation, fibrosis activity or myocardial function. CD4+ and CD8+ T cells also did not differ by treatment group. Losartan reduced SBP and DBP by 6 and 5 mmHg, respectively. Conclusion: Among older PHIV with viral suppression, losartan did not improve blood measures of inflammation nor T-cell immune recovery. Losartan treatment is unlikely to reduce inflammation associated comorbidities to a clinically meaningful degree, beyond the benefits from lowering blood pressure. ClinicalTrials.gov: NCT02049307.

ABSTRACT HIV protease is known to cause cell death, which is dependent upon cleavage of procaspase 8. HIV protease cleavage of procaspase 8 generates Casp8p41, which directly binds Bak with nanomolar affinity, causing Bak activation and consequent cell death. Casp8p41 can also bind Bcl2 with nanomolar affinity, in which case cell death is averted. Central memory CD4 T cells express high levels of Bcl2, possibly explaining why those cells do not die when they reactivate HIV. Here, we determine that the Casp8p41-Bcl2 complex is polyubiquitinated and degraded by the proteasome. Ixazomib, a proteasome inhibitor in clinical use, blocks this pathway, increasing the abundance of Casp8p41 and causing more cells to die in a Casp8p41-dependent manner. IMPORTANCE The Casp8p41 pathway of cell death is unique to HIV-infected cells yet is blocked by Bcl2. Once bound by Bcl2, Casp8p41 is polyubiquitinated and degraded by the proteasome. Proteasome inhibition blocks degradation of Casp8p41, increasing Casp8p41 levels and causing more HIV-infected cells to die.

Background HIV infection leads to activation of coagulation, which may increase the risk for atherosclerosis and venous thromboembolic disease. We hypothesized that HIV replication increases coagulation potentially through alterations in extrinsic pathway factors. Methods and Results Extrinsic pathway factors were measured among a subset of HIV participants from the Strategies for Management of Anti‐Retroviral Therapy ( SMART ) trial. Thrombin generation was estimated using validated computational modeling based on factor composition. We characterized the effect of antiretroviral therapy ( ART ) treatment versus the untreated state ( HIV replication) via 3 separate analyses: (1) a cross‐sectional comparison of those on and off ART (n=717); (2) a randomized comparison of deferring versus starting ART (n=217); and (3) a randomized comparison of stopping versus continuing ART (n=500). Compared with viral suppression, HIV replication consistently showed short‐term increases in some procoagulants (eg, 15% to 23% higher FVIII ; P <0.001) and decreases in key anticoagulants (eg, 5% to 9% lower antithrombin [ AT ] and 6% to 10% lower protein C; P <0.01). The net effect of HIV replication was to increase coagulation potential (eg, 24% to 48% greater thrombin generation from computational models; P <0.01 for all). The pattern of changes from HIV replication was reversed with ART treatment and consistent across all 3 independent comparisons. Conclusions HIV replication leads to complex changes in extrinsic pathway factors, with the net effect of increasing coagulation potential to a degree that may be clinically relevant. The key influence of changes in FVIII and AT suggests that HIV ‐related coagulation abnormalities may involve changes in hepatocyte function in the context of systemic inflammation. Clinical Trial Registration URL: ClinicalTrials.gov . Unique identifier: NCT 00027352.