Day ± window	Screen	Baseline	Daily until discharge	6 ± 2	15 ± 2	29 ± 3	5–7 weeks post-discharge	Day 90
	− 3 to 0	0
Assessments/procedures
Eligibility
Informed consent	X
Demographics and medical history	X
Review COVID-19 criteria	X
Inclusion and exclusion criteria	X
Studyintervention
Randomization		X
Administration of study drug		X	Daily for 5 days
Studyprocedures
Vital signs including SpO2	X	X	Daily until discharge
Clinical data collection	X	X	Daily until discharge				X
Targeted medication review	X	X	Daily until discharge				X
Adverse event evaluation	X	X	Daily until discharge				X
ECGb	X	X	QT monitoring scheme
Evaluation by telephone					X	X	If outpatient visit is not feasible	x
Evaluation on outpatient clinic							Xa
Spirometry + reversibility							Xa
Lung volumes + diffusion							Xa
Low-dose CT scan							Xa
6-min walking distance							Xa
Laboratory
CRP, hematology, chemistry, kidney and liver test	X	At clinician’s discretion	At clinician’s discretion				Xa
Pregnancy test for females of childbearing potential	X
Viral qPCR (nasopharyngeal swab)				If feasible

^aIf clinically feasible

^bQT monitoring scheme: Long QT (> 470 ms males and > 480 females) is an exclusion for participation. In patients with no long QT on ECG but at risk, a QT monitoring will be performed with intermittent ECG monitoring at days 2–3 or continuous follow-up on ICUs. When QTc > 500 ms and/or delta QTc > 60 ms, IMP will be interrupted/discontinued at the discretion of the investigator. The patient’s medication will be reviewed daily to evaluate DDIs including drugs prolonging the QTc interval according to what is listed in the protocol (see Additional file 1)