COVID-19 outcomes are linked to host immune responses and may be impacted by antiviral therapy. We investigated antibody and cytokine responses in ACTT-1 study participants enrolled at our center. We studied serum specimens from 19 hospitalized adults with COVID-19 randomized to treatment with remdesivir or placebo. We assessed SARS-CoV-2 antibody responses and identified cytokine signatures using hierarchical clustering. We identified no clear immunologic trends attributable to remdesivir treatment. Seven subjects were initially seronegative at study enrollment, and all four deaths occurred in this group with more recent symptom onset. We identified three dominant cytokine signatures, demonstrating different disease trajectories.