The first clinical results for remdesivir’s effectiveness on severe COVID-19 demonstrated clinical improvements but remain unclear due to the fact that no control group was included in the study.
The research, published in the New England Journal of Medicine, followed 53 patients in the US, Europe, Canada and Japan who were who were given compassionate use authorizations. Patients had confirmed COVID-19, had SpO2 of 94% or less and other clinical characteristics. 
Patients were administered a initial dose of 200 mg remdesivir on Day 1 followed by nine days of 100 mg with supportive therapy. Patients were observed until death or discharge at Day 28. Seventy-five percent received the full 10-day course, 10 received 5 to 9 days of treatment, and 3 fewer than 5 days of treatment. At the start of the study, 30 patients were receiving mechanical ventilation and four were on ECMO. 
According to results, clinical improvement was observed in 84% of patients overall, with 36 of 53 recording improvements in oxygen support status. However, researchers noted less frequent improvement for invasive ventilation than noninvasive ventilation. A total of 25 patients were discharged, and 7 patients died. 
Seventeen of 30 intubated patients were extubated, while six patients died. Mortality was 18% (6 of 34) among patients receiving invasive ventilation and 5% (1 of 19) among those not receiving invasive ventilation. 
However, the lack of any placebo-based or standard-care control groups in the study mean no conclusions can be drawn on the effectiveness of the drug.
“Interpretation of the results of this study is limited by the small size of the cohort, the relatively short duration of follow-up, potential missing data owing to the nature of the program, the lack of information on 8 of the patients initially treated, and the lack of a randomized control group,” the authors wrote.
According to AP News, there are five clinical trials of the drug ongoing, involving 1,700 patients receiving remdesivir.
Source: Grein J, et al. Compassionate Use of Remdesivir for Patients with Severe Covid-19. NEJM. 2020 Apr 10. Accessed: DOI: 10.1056/NEJMoa2007016