Investigation of Choice Alteration of the Gut Metagenome on COVID-19 Severity
Phase: PHASE1
Conditions: COVID-19 Infection
Sponsor: Vanderbilt University Medical Center

 
Version 1.0 
March 13, 2021 
 
Page 1 of 32 
 
 
Investigation of Choice Alteration of the Gut Metagenome on COVID-19 Severity 
 
Investigation of CHoice AlteratioN of Gut metagenomE on COVID-19 Severity  
Short Name: “CHANGE COVID-19 Severity”  
 
Protocol Version:  1.0 
Date: March 13, 2021 
 
 
 
 
 
 
 

 
Version 1.0 
March 13, 2021 
 
Page 2 of 32 
ABBREVIATIONS 
 
ACE-I 
Angiotensin-converting-enzyme inhibitor 
ARB 
Angiotensin II receptor blocker 
ADR 
Adverse drug reaction 
AE 
Adverse event 
DSMB 
Data safety monitoring board 
eCRF 
Electronic case report forms 
GFR 
Glomerular filtration rate 
ICU 
Intensive care unit 
IV 
Intravenous 
LAR 
Legally authorized representative 
LFT 
Liver function test 
MIC 
Minimum inhibitory concentration 
NSAIDs 
Nonsteroidal anti-inflammatory drug 
PI 
Principal investigator (a clinician responsible for one site) 
RCT 
Randomized control trial 
SAE 
Serious adverse events 
S/F 
SpO2/FiO2 ratio 
SOC 
Standard of Care 
SOFA 
Sequential Organ Failure Assessment 
SOP 
Standard operating Procedure 
 
 
 
 
 
 
 

 
Version 1.0 
March 13, 2021 
 
Page 3 of 32 
1.0 Protocol Synopsis 
 
Study Design 
Blinded, single-center, placebo-controlled randomized clinical trial 
 
Study Aim 
To compare the effect of oral magnesium citrate plus a the probiotic Floranex versus placebo on clinical 
outcomes, determined by the oxygen area under the curve, among adults with COVID-19 requiring 
hospitalization.  
 
Primary Outcome 
1. Change in COVID Ordinal Outcome Scale (Appendix E) through Day 7 after completion of therapy 
 
Secondary Outcomes 
1.   Time to recovery, which is the time to the earlier of final liberation from supplemental oxygen or hospital 
discharge 
2. Hospital mortality to 28-day mortality (assessed on Study Day 29 from randomization) 
3. Time to discharge to 28 days after treatment 
4. Quantitative change in nasal viral titer 
5. Change in systemic CD4+ and CD8+ T cell cytokine expression 
6. Change in Oxygen AUC of SaO2/FiO2 through Day 7 
7. Quantitative change in systemic immune profile 
8. Oxygen-free days through Day 28 
9. Ventilator-free days through Day 28 
10. Vasopressor-free days through Day 28 
11. ICU-free days through Day 28 
12. Hospital-free days through Day 28 
 
Inclusion Criteria 
 
1. Age ≥18 years 
2. Currently hospitalized or in an emergency department with anticipated hospitalization. 
3. Symptoms of acute respiratory infection, defined as one or more of the following: 
a. Cough 
b. Fever (> 37.5° C / 99.5° F) 
c. Shortness of breath (operationalized as any of the following: subjective shortness of breath 
reported by patient or surrogate; tachypnea with respiratory rate ≥22 /minute; hypoxemia, defined 
as SpO2 <92% on room air, new receipt of supplemental oxygen to maintain SpO2 ≥92%, or 
increased supplemental oxygen to maintain SpO2 ≥92% for a patient on chronic oxygen therapy). 
d. Sore throat 
e. Anosmia 
4. Laboratory-confirmed SARS-CoV-2 infection within 10 days prior to randomization 
5. Ability to manage own stool care  
 
Exclusion Criteria 
1. Pregnancy  
2. Breast feeding 

 
Version 1.0 
March 13, 2021 
 
Page 4 of 32 
3. Mechanical ventilation 
4. Current infectious or noninfectious diarrheal illness 
5. Unable to randomize within 21 days after onset of acute respiratory infection symptoms  
6. Unable to randomize after hospital arrival 
7. Colonic obstruction 
8. Unresolved hypovolemia  
9. Hypermagnesemia  
10. Diagnosis of long QT syndrome 
11. Known allergy to magnesium citrate the probiotic Floranexs 
12. Unresolved electrolyte imbalance, such as hypokalemia or hypocalcemia.  
13. Receipt of >1 dose of magnesium citrate, the probiotic Floranex or any other colonic cleansing agent 
within 7 days prior to enrollment 
14. Inability to receive enteral medications 
15. Refusal or inability to be contacted on Day 7 for clinical outcome assessment if discharged prior to Day 7 
16. Concurrent medical illness that interferes with clinical assessments 
17. The treating clinical team does not believe equipoise exists regarding the use of magnesium citrate plus 
a the probiotic Floranex for the treatment of this patient 
18. Immunologically vulnerable patients, such as AIDS patients or neutropenic patients 
19. Participating in any other COVID-19 therapeutic trials. 
 
Randomization 
Eligible participants will be randomized 1:1 to magnesium citrate plus the probiotic Floranex versus placebo. 
Placebo will be carbonated lemon water for magnesium citrate and over-encapsulated microcrystalline pills for 
Floranex.  Randomization will be completed in permuted blocks of variable size. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
Version 1.0 
March 13, 2021 
 
Page 5 of 32 
2. TRIAL DESCRIPTION 
 
2.1 Background 
Coronavirus Disease 2019 (COVID-19) is an acute respiratory infectious illness caused by severe acute 
respiratory syndrome coronavirus 2 (SARS-CoV-2).1,2  Although the epidemiology has not been fully elucidated, 
most adults with COVID-19 appear to experience fever, cough, and fatigue and then recover within 1-3 weeks.  
However, a portion of adults with COVID-19 develop severe illness, typically manifesting as pneumonia and 
hypoxemic respiratory failure, with continued progression to acute respiratory distress syndrome (ARDS) and 
death in some cases.1–3  The incidence and mortality of COVID-19 cases continues to climb in the United States, 
as well as around the world.  While progress for vaccination and identifying therapeutics against SAR-CoV-2 
have emerged, the limitations continue to emerge.  For example, convalescent plasma was recently demonstrated 
to hold little promise against COVID-19 severe pneumonia[1].  While remdesivir demonstrates efficacy in 
hospitalized COVID-19 patients with pneumonia[2], the NIH no longer recommends remdesivir with 
dexamethasone as an option for hospitalized COVID-19 patients who require mechanical ventilation or ECMO, 
recommending only dexamethasone instead (COVID-19 Treatment Guidelines Panel. Coronavirus Disease 2019 
(COVID-19) Treatment Guidelines. National Institutes of Health. Available at 
https://www.covid19treatmentguidelines.nih.gov/. Accessed 12/07/2020).   Thus, data on the safety and 
effectiveness of magnesium citrate plus  the probiotic Floranex for the treatment of COVID-19 are urgently 
needed to inform clinical practice.  In this trial, we will evaluate the safety and effectiveness of magnesium citrate 
plus the probiotic Floranex for the treatment of adults hospitalized with COVID-19.  
 
2.1.1 COVID-19 Infection 
COVID-19 was first identified as a cluster of cases of pneumonia among a group of workers from a seafood 
wholesale market in Wuhan, China in December 2019.7  This observation, along with subsequent viral genotyping 
showing significant genetic similarities to the bat coronaviruses8 suggest a zoonotic origin, although the specific 
reservoir and  intermediary species remain unclear.9  The COVID-19 infection represents the seventh coronavirus 
known to cause disease in humans.10  Four of the coronaviruses viruses are known to cause symptoms of the 
common cold in immunocompetent individuals while two others (SARS-CoV and MERS-CoV) have caused 
recent outbreaks of severe and sometimes fatal respiratory diseases.11 SARS-CoV-2 appears to exploit the same 
cellular receptor as SARS-CoV and MERS-CoV,12 and its severity may similarly result from a predilection for 
intrapulmonary epithelial cells over cells of the upper airways.13,14   Since the first documented human case, 
COVID-19 has spread exponentially within the United States with 14,823,129  confirmed cases and 282,785 
deaths as of December 8, 2020.  While most patients recover after a mild, brief illness with fever and cough, the 
disease has a clinical spectrum ranging from asymptomatic infection15 to ARDS and death.16  The most common 
reasons for ICU care are respiratory failure and ARDS, with a minority developing shock and possibly 
cardiomyopathy.17 The case fatality rate is estimated to be 0.25% to 3.0%.18   
 
2.1.2 Magnesium citrates as a Therapeutic for COVID-19 
Recent recommendations, such as the cessation of remdesivir in intubated COVID-19 patients with severe 
pneumonia, illustrates as important clinical observation:  much of COIVD-19 mortality occurs after the virus has 
been cleared.  Viral clearance typically occurs 9-20 days after symptom onset[3].   A similar monkey model of 
SARS-CoV infection in the African Green Monkey demonstrated clearance of virus from nasal turbinate, 
nasopharynx, tracheal, proximal and distal lungs within 5-10 days after infection[4].  Similarly, investigators 
reported that viral loads in SARS-CoV-2–challenged rhesus macaques remain elevated for 10-28 days following 
primary challenge[5].  
     A common clinical factor found in persons at risk for COVID-19 severity, such as aging, obesity, diabetes and 
hypertension, is gut dysbiosis and resulting low grade inflammation with loss of epithelial barrier function[6, 7].  
A recent study noted  that compared with healthy controls, COVID-19 patients had significantly reduced bacterial 
diversity, a significantly higher relative abundance of opportunistic pathogens, such as Streptococcus, Rothia, 
Veillonella and Actinomyces, and a lower relative abundance of beneficial symbionts[8, 9].  Another investigation 

 
Version 1.0 
March 13, 2021 
 
Page 6 of 32 
of faecal samples with signature of high SARS-CoV-2 infectivity had higher abundances of bacterial species, 
such as Collinsella aerofaciens, Collinsella tanakaei, Streptococcus infantis, Morganella morganii, and higher 
functional capacity for nucleotide de novo biosynthesis, amino acid biosynthesis and glycolysis, whereas faecal 
samples with signature of low-to-none SARS-CoV-2 infectivity had higher abundances of short-chain fatty acid 
producing bacteria, Parabacteroides merdae, Bacteroides stercoris, Alistipes onderdonkii and Lachnospiraceae 
bacterium in the stool of COVID-19 patients[10].  These observations support assessing for host metagonomic 
contributors to COVID-19 morbidity and mortality.   
     Alterations of the microbiota that lead to intestinal dysbiosis (a microbial imbalance within the intestinal tract) 
are characterized by a loss or significant decrease in the amount of beneficial bacterial species and/or an outgrowth 
or population shift of pathogenic species.  A growing body of literature implicates the role of the gut microbiome 
in the severity of chronic viral infections. Perturbation of the gut microbiota during influenza A virus (IAV) 
infection might favor respiratory bacterial superinfection[11]. Alterations in the gut microbiome itself may affect 
influenza severity.  In general, mice treated with broad spectrum antibiotics display diminished innate and adaptive 
immune responses, characterized by reduced expression of antiviral genes in alveolar macrophages, more severe 
bronchiole epithelial degeneration, and higher viral loads compared to untreated mice[12].   Laboratory mice 
reconstituted with natural microbiota exhibited reduced inflammation and increased survival following influenza 
virus infection and improved resistance against mutagen/inflammation-induced colorectal tumorigenesis[13].  It has 
been suggested that gut microbiota can fine-tune the threshold of antiviral immune responses[14], possibly through 
metabolites such as short chain fatty acids (SCFAs). The critical role of SCFAs in the gut-lung axis is well-
recognized, and studies in a mouse model have shown that consumption of SCFAs reduces inflammatory symptoms, 
and also decreases allergenic diseases in the airway though suppression by regulatory T (Treg) cells[15].  Indeed 
independent reports suggest that alteration of the gut microbiome may positively affect COVID-19 severity.  
Suggestions, such as the probiotic Floranex and high fiber diets, have been postulated to reduce COVID-19 
severity[16]; however, that ability of such interventions to rapidly affect alter the gut microbiome in hospitalized 
patients, and thus potentially reduce COVID-19 severity, are limited.   
     Recent investigations of chemical induction of acute lung inflammation demonstrates significant reductions in 
lung injury among mice housed in germ-free environments (Dr. Wonder Drake, manuscript in preparation).  Also, 
administration of colonic cleansing via magnesium citrate in three hypoxic, COVID-19 patients with pneumonitis 
resulted in significant clinical improvement within 24-72  hours (Dr. Wonder Drake, manuscript in preparation). 
 
2.1.3 Rationale for a Randomized Trial among Hospitalized Patients 
The initial symptoms of COVID-19 develop approximately 2-10 days after infection with the SARS-CoV-2 
virus,23 with the progression to respiratory failure and ARDS occurring approximately 7-10 days after the onset of 
symptoms.24  While most adults with COVID-19 recover without complications, patients who require 
hospitalization experience high rates of complications. In case series of hospitalized patients with COVID-19, up 
to 26% require ICU admission and up to 17% die in the hospital.24,25  The period between onset of symptoms and 
development of severe respiratory failure represents a potential window for treatment of hospitalized patients to 
prevent disease progression.  
 
Given the unprecedented public health crisis caused by COVID-19, there is significant interest in finding effective 
therapies and, specifically, in repurposing approved medications with widespread availability and known safety 
profiles.3,26   
Data on the safety and efficacy of magnesium citrate from randomized trials is urgently needed.  A randomized 
clinical trial demonstrating that magnesium citrate prevents disease progression in hospitalized patients with 
COVID-19 would provide evidence-based therapy for an ongoing pandemic, as well as important public health 
impact.    
Given the need for effective treatments of COVID-19 and  the unclear efficacy and safety of magnesium citrate as 
a treatment of COVID-19a randomized clinical trial is urgently needed. 
 
2.1.4. Rationale for Evaluating Magnesium Citrate in addition to standard therapy 
Current therapeutics for COVID-19 include remdesivir, with the caveat of therapeutic limitations among patients 
who are intubated or on ECMO.  While we propose the use of magnesium citrate and  the probiotic Floranex in 

 
Version 1.0 
March 13, 2021 
 
Page 7 of 32 
non-ICU, COVID-19 subjects, any observed clinical benefit will subvert disease progression.  During the design 
of this protocol, the investigators propose to add Magnesium citrate in addition to current therapy.   Current 
COVID-19 therapeutics will not interfere with the therapeutic benefit of magnesium citrate, and fortunately, the 
converse is also true.  Interpretation of a trial of one agent will be straightforward and may provide the basis for 
subsequent trials of patients with more severe COVID-19 manifestations.   
 
2.2 Study Aims  
2.2.1 Study aim 
To compare the efficacy of magnesium citrate plus the probiotic Floranex versus placebo on physiology, 
immunologic and clinical outcomes among adults hospitalized due to COVID-19 infection.  
 
2.2.2 Study hypothesis 
Among adults hospitalized with COVID-19, administration of magnesium citrate plus  the probiotic Floranex will 
improve clinical outcomes by Day 28.  
 
2.3 Study Design 
We will conduct an investigator-initiated, single center, blinded, placebo-controlled, randomized clinical trial 
evaluating magnesium citrate plus  the probiotic Floranex for the treatment of adults hospitalized with COVID-
19. Patients, treating clinicians, and study personnel will all be blinded to study group assignment.     
 
2.4 Outcomes 
Primary Outcome 
1. Change in WHO Clinical Progression Scale through Day 7 after completion of therapy 
 
Secondary Outcomes 
1.   Time to recovery, which is the time to the earlier of final liberation from supplemental oxygen or hospital 
discharge 
2. Hospital mortality to 28-day mortality (assessed on Study Day 29 from randomization) 
3. Time to discharge to 28 days after treatment 
4. Quantitative change in nasal viral titer 
5. Change in systemic CD4+ and CD8+ T cell cytokine expression 
6. Change in Oxygen AUC of SaO2/FiO2 through Day 7 
7. Quantitative change in systemic immune profile 
8. Oxygen-free days through Day 28 
9. Ventilator-free days through Day 28 
10. Vasopressor-free days through Day 28 
11. ICU-free days through Day 28 
12. Hospital-free days through Day 28 
 
 
3. STUDY POPULATION AND ENROLLMENT 
 
3.1 Inclusion Criteria 
1. Age ≥18 years 
6. 2. Currently hospitalized or in an emergency department with anticipated hospitalization. 
7. 3. Symptoms of acute respiratory infection, defined as one or more of the following: 
a. Cough 

 
Version 1.0 
March 13, 2021 
 
Page 8 of 32 
b. fever (> 37.5° C / 99.5° F) 
c. shortness of breath (operationalized as any of the following: subjective shortness of breath 
reported by patient or surrogate; tachypnea with respiratory rate ≥22 /minute; hypoxemia, defined 
as SpO2 <92% on room air, new receipt of supplemental oxygen to maintain SpO2 ≥92%, or 
increased supplemental oxygen to maintain SpO2 ≥92% for a patient on chronic oxygen therapy). 
d. sore throat 
4. Laboratory-confirmed SARS-CoV-2 infection within 10 days prior to randomization  
 
Exclusion Criteria 
1. Prisoner 
2. Pregnancy  
3. Breast feeding 
4. Current infectious or noninfectious diarrheal illness 
5. Unable to randomize within 21 days after onset of acute respiratory infection symptoms  
6. Unable to randomize  after hospital arrival 
7. Colonic obstruction 
8. Unresolved hypovolemia  
9. CrCl <30ml/min 
10. Hypermagnesemia  
11. Diagnosis of Long QT syndrome 
12. Known allergy to magnesium citrate or the probiotic Floranex  
13. Unresolved electrolyte imbalance such as hypokalemia or hypocalcemia. The patient can be enrolled if 
electrolytes are corrected and sustained.   
14. Receipt of >1 dose of magnesium citrate or any other colonic cleanser in the  7 days prior to enrollment 
15. Inability to receive enteral medications 
16. Refusal or inability to be contacted on Day 15 for clinical outcome assessment if discharged prior to Day 
15 
17. Concurrent medical illness that interferes with clinical assessmentPrevious enrollment in this trial 
18. The treating clinical team does not believe equipoise exists regarding the use of magnesium citrate plus 
the probiotic Floranex for the treatment of this patient. 
19. Participating in any other COVID-19 therapeutic trial 
 
3.3 Justification of Exclusion Criteria 
The exclusion criteria are primarily designed for patient safety.  In addition to excluding specific vulnerable 
populations (e.g., prisoners), these criteria are designed to exclude patients for whom receipt of magnesium citrate 
plus a the probiotic Floranex might increase the risk of serious adverse events.   
 
3.4 Screening 
The site investigator or delegate will screen for hospitalized patients with laboratory confirmed COVID-19 (that 
is, a positive laboratory test for SARS-CoV-2) or a pending SARS-CoV-2 test.  Treating clinicians will also be 
instructed to contact the site investigator or delegate for patients with a high clinical suspicion of COVID-19.   
 
3.5 Assessment of Eligibility and Exclusion Tracking 
For patients who appear to meet inclusion criteria during screening, an electronic case report form will be 
completed to determine eligibility and track exclusions.  The electronic case report form will be accessed and 

 
Version 1.0 
March 13, 2021 
 
Page 9 of 32 
stored in the electronic database.  At the time of entry into the screening database, the patient will be assigned a 
screening number.  
If a patient appears to meet all eligibility criteria, the site investigator or delegate will approach the treating 
clinician to ask permission to approach the patient or Legally Authorized Representative (LAR) to confirm 
eligibility, discuss potential study recruitment, and proceed with informed consent.   
For all excluded patients, including refusal by the treating clinician or patient/surrogate, a small number of de-
identified variables will be collected including month and year the patient met screening criteria, age, sex, 
ethnicity, patient location, and reason(s) patient was excluded.  For the safety of research personnel and 
conservation of personal protective equipment, these encounters may occur via telephone or videophone.  
 
3.6 Process of Obtaining Informed Consent 
Informed consent will be obtained from the patient or from a surrogate decision maker if the patient lacks 
decision-making capacity.    
In some instances, bringing a paper consent form and pen to the bedside of a patient with known or suspected 
COVID-19 and then taking these out of the room would violate infection control principles and policies.  Given 
the infectious risk from COVID-19 and potential shortages of personal protective equipment (PPE), there is a 
moral and practical imperative to minimize face-to-face contact between patients and non-clinical personnel.  The 
current epidemic also presents unique challenges to obtaining consent from participant’s legally authorized 
representative (LAR).  To minimize infectious risk, many institutions are not allowing visitors to enter the 
hospital. Furthermore, the LAR is likely to have been exposed to the patient and may therefore be under self-
quarantine at the time of the informed consent discussion. 
Therefore, in addition to the traditional approach of an in-person consent discussion and signed paper informed 
consent document, we will allow use of “no-touch” consent procedures for this trial.  Below, we outline three 
examples of no-touch consent procedures that may be used: (a) a paper-based approach; (b) attestation of 
informed consent.   
 
3.6.1 Paper-based approach 
1. The informed consent document is delivered to the patient or LAR. 
a. If the patient or LAR is on-site, the informed consent document many be delivered to the patient 
or LAR either by research staff or by clinical staff 
b. If the LAR is off-site, the informed consent document may be emailed, faxed, or otherwise 
electronically transferred to the LAR (method dictated by institutional policy) 
2. Research staff discuss the informed consent document with the patient or LAR either in-person or by 
telephone or videophone.  This step confirms subject/LAR identity. 
3. If the patient or LAR decides to consent to participate, the patient or LAR signs the paper copy of the 
informed consent document. 
4. A photograph is taken of the signature page of the informed consent document and uploaded into the 
electronic database (e.g. REDCap).  
a. If using the patient’s device (such as a patient’s personal cellular phone), a survey link can be sent 
to their device to allow direct upload of the image into the electronic database (e.g. REDCap). 
b. If using a staff device, it must be approved to store PHI by the local institution. In that case, 
research personnel can take a photograph of the signature page of the informed consent document 
either directly or through the window or glass door leading into the patient’s room.  The 
photograph can then be uploaded into the electronic database.  If a staff device is taken into the 
patient’s room to take a photograph it must be able to be disinfected according to local 
institutional practices.  
5. Research staff and witness provide signatures within the electronic database (e.g. REDCap) confirming 
their participation in the informed consent process. 

 
Version 1.0 
March 13, 2021 
 
Page 10 of 32 
6. The patient or LAR retains the paper consent document. The image of the signature page may be printed 
and bundled with a copy of the blank informed consent document for research records. 
 
 
If a hospital device is provided to facilitate electronic or paper-based consent, that device will be disinfected 
according to institutional protocols and removed by research staff or clinical staff during the next entry into the 
patient’s room. 
This approach complies with relevant regulations and sub-regulator guidance at 45 CFR 46.117, 45 CFR 164.512, 
21 CFR 11 Subpart C (11.100–11.300), https://www.hhs.gov/ohrp/regulations-and-policy/guidance/use-
electronic-informed-consent-questions-and-answers/index.html, https://www.fda.gov/regulatory-
information/search-fda-guidance-documents/informed-consent 
The information for the informed consent discussion will be provided in a formal document (or electronic 
equivalent) that has been approved by the IRB and in a language comprehensible to the potential participant, 
using an interpreter if necessary. The information presented in the consent form and by the research staff will 
detail the nature of the trial and what is expected of participants, including any potential risks or benefits of taking 
part. It will be clearly stated that the participant is free to withdraw from the trial at any time for any reason 
without prejudice to future care, and with no obligation to give the reason for withdrawal. Where a patient does 
not speak English, a short-form consent and qualified interpreter will be employed, using similar “no-touch” 
principles.  Use of an interpreter and the interpreter’s identity will be documented on the electronic consent. 
 
   
3.7 Randomization and Blinding  
Participants confirmed to meet all eligibility criteria who have provided informed consent will be randomized 1:1 
to magnesium citrate plus a the probiotic Floranex versus placebo.  A randomization code will be provided to the 
site investigator or delegate from a centralized, web-based platform.  Randomization will require provision of the 
screening number and confirmation of patient eligibility. 
Randomization will be completed in permuted blocks of varying size and stratified by site. The randomized 
sequence allocation will be stored on a secure server and will not be available to site study personnel. Site 
research personnel will have a unique Personal Identification Number (PIN) to access the randomization system. 
Each subject will receive a computer-generated randomization ID number.  The computer-generated 
randomization ID number will be provided to the pharmacy who will provide a dose pack containing magnesium 
citrate plus a the probiotic Floranex or placebo.  The participant, treating clinicians, study personnel, and outcome 
assessors will all remain blinded to group assignment until after the database is locked and blinded analysis is 
completed. 
 
3.8 Minorities and Women 
No patients will be excluded on the basis of race, ethnicity, or sex. The clinical coordinating center will monitor 
recruitment of minorities and women. If necessary, additional recruitment efforts will be made to ensure that the 
aggregate patient sample contains representative race/ethnicity and sex subsets. 
 
 
4. STUDY INTERVENTIONS 
 
4.1 Treatment of Study Participants 
A summary of the trial’s schedule of events is included in Appendix A.  
Timing of study procedures is based on the time of randomization, which is defined as “Time 0”.    The primary 
outcome will be assessed on Study Day 7, which corresponds to 7 days after randomization.  
Study medications will be administered by clinical or research personnel while the patient is hospitalized. The 
study medication will be administered within 4 hours of randomization. On Study Day 1, study personnel will 
review patient records to confirm administration of the study drug and document the volume of magnesium citrate 

 
Version 1.0 
March 13, 2021 
 
Page 11 of 32 
and the probiotic Floranex was consumed.  Research personnel will assess patients at Day 1-5, 7 and through Day 
29; these assessments will be completed by phone if the patient has been discharged from the hospital.  
 
4.2 Study Arms 
Magnesium Citrate plus The probiotic Floranex Arm: 
Participants assigned to the magnesium citrate plus  the probiotic Floranex arm will receive 1 bottle of magnesium 
citrate 296 mL PO once to be taken within a 4-hour period, (about 10 oz.).  Because magnesium citrate remains 
within the intestinal lumen, a second bottle can be provided if there is limited bowel movement.  Patients will be 
asked to take 2 capsules of the probiotic Floranexs twice daily for six days or until discharge, whichever is earlier. 
 
Placebo Arm 
Participants randomized to the placebo arm will receive matching carbonated lemon water 296 mL PO once to be 
taken within a 4-hour period, (about 10 oz.) and 2 over-encapsulated microcrystalline pills capsules twice daily 
for six days or until discharge, whichever is earlier. The placebo will be flavored to match the taste of the 
interventional arm. 
 
4.4 Co-Interventions 
This trial will control the use of magnesium citrate plus  the probiotic Floranex vs placebo during the intervention 
period.  Enrolled participants will not receive open-label magnesium citrate or the probiotic Floranex during the 
intervention period. All other treatment decisions will be made by treating clinicians without influence from the 
protocol.  Administration of other antiviral medications (“rescue therapy”) will be allowed.  The decision to 
administer other antiviral medications will be made by treating clinicians and will be recorded in the case report 
form. The decision to administer immunomodulating medications, including corticosteroids, will be made by 
treating clinicians and will be recorded in the case report from.   
 
4.5 On-Study Monitoring 
All patients enrolled in the study will be initially hospitalized and will therefore receive monitoring as a part of 
routine clinical care, including monitoring by their physicians, nurses, respiratory therapists, and ancillary staff. 
 
Study personnel will review the electronic health record daily for new potential medication interactions with 
magnesium citrate (see Appendix B).  If a medication that is considered to be contraindicated with magnesium 
citrate or the probiotic Floranexs is discovered, treating clinicians will be contacted to discuss if stopping study 
drugs is appropriate or if the medication in question can be stopped or substituted.  If a medication with a 
potential interaction with magnesium citrate or the probiotic Floranex is identified, study personnel will contact 
treating clinicians to ensure they are aware of the potential interaction.  Treating clinicians will determine whether 
an alternative medication would be appropriate or whether the risk-benefit ratio favors continuing the medication 
with the known potential interaction.   
In addition to manual monitoring by study personnel for medication interactions, many electronic health records 
contain tools within the electronic order entry system to automatically screen for medication interactions and 
notify ordering providers of the potential interaction at the time of order entry. 
 
4.6 Criteria for Stopping Study Drug 
Administration of the blinded study drug may be stopped temporarily or permanently for (a) adverse events, (b) 
results of on-study monitoring, (c) clinical deterioration, or (d) evidence of an alternative cause to the patient’s 
symptoms.   
If a patient experiences an adverse event that the patient (or legally authorized representative), treating clinicians, 
or investigators feel merits temporarily or permanently stopping the study drug, the study drug will be stopped. 
The explanation for stopping the study drug will be recorded in the case report form, and the adverse event will be 
recorded and reported according to the adverse event guidelines below.  If the adverse event resolves to the extent 
that the patient (or legally authorized representative), treating clinicians, and investigators feel that resuming the 

 
Version 1.0 
March 13, 2021 
 
Page 12 of 32 
study drug is appropriate, the study drug will be resumed, and this information will be recorded in the case report 
form.   
Patients on study may experience clinical deterioration due to their illness.  Clinical deterioration will be defined 
as a decrease of 1 point or more on the ordinal scale for the primary outcome (e.g., patient transitions from 
“hospitalized on supplemental oxygen” to “hospitalized on non-invasive ventilation or high flow nasal cannula”).  
Patients who experience clinical deterioration in either group may be administered other antivirals or 
immunomodulators as “rescue therapy”.  For patients who experience clinical deterioration for which treating 
clinicians feel optimal care would be to stop the study drug, unblind group assignment, and administer 
magnesium citrate and/or the probiotic Floranex to patients in the placebo group, the study drug will be stopped, 
the site investigator will contact the coordinating center to receive the unblinded study group assignment, and any 
additional treatment will be deferred to treating clinicians.  In this situation, the following data will be recorded in 
the case report form: the criteria met for clinical deterioration; the reason for stopping study drug and unblinding; 
use of magnesium citrate, other antivirals, and immunomodulators; and study outcomes.  
 
 
5. OUTCOMES 
 
5.1 Primary Outcome  
1. Change in WHO Clinical Progression Scale through Day 7 after completion of therapy 
 
5.2 Secondary Outcomes 
1.   Time to recovery, which is the time to the earlier of final liberation from supplemental oxygen or hospital 
discharge 
2. Hospital mortality to 28-day mortality (assessed on Study Day 29 from randomization) 
3. Time to discharge to 28 days after treatment 
4. Quantitative change in nasal viral titer 
5. Change in systemic CD4+ and CD8+ T cell cytokine expression 
6. Change in Oxygen AUC of SaO2/FiO2 through Day 7 
7. Quantitative change in systemic immune profile 
8. Oxygen-free days through Day 28 
9. Ventilator-free days through Day 28 
10. Vasopressor-free days through Day 28 
11. ICU-free days through Day 28 
12. Hospital-free days through Day 28 
 
5.3 Safety outcomes 
• Dehydration 
• Symptomatic Hypotension 
• Acute kidney injury 
• Receipt of renal replacement therapy 
 
5.4 Rationale for Primary Outcome 
COVID-19 has a broad spectrum of clinical severity.   Even among hospitalized patients, most recover without 
experiencing critical illness.30  Designing a trial with statistical power to detect a meaningful difference in ICU-
free days or mortality might require an unfeasibly large sample size and could miss significant morbidity 
experienced by the majority of hospitalized patients.  Since the majority of morbidity from COVID-19 relates to 
hypoxemia, the fact that this outcome is tied to degree of hypoxemic respiratory failure increases its face validity 
and relevance.  For similar reasons, previous trials of severe influenza have employed a similar ordinal outcome.31  

 
Version 1.0 
March 13, 2021 
 
Page 13 of 32 
This ordinal scale has been selected as an outcome in multiple ongoing COVID-19 trials and is a preferred 
outcome by the World Health Organization Research and Development Blueprint for COVID-19.32 Use of this 
standardized outcome will increase the potential to compare the results of this trial with other trials and perform 
meta-analyses. 
 
6. STUDY ASSESSMENTS, PROCEDURES AND DATA COLLECTION  
Given the infectious risk from COVID-19 and potential shortages of personal protective equipment (PPE), we 
will minimize face-to-face contact between patients and non-clinical staff.  Additionally, minimizing research 
activities and conducting the trial in a pragmatic manner will increase the ability to complete the trial in the face 
of strained clinical and research resources during the COVID-19 pandemic. We will emphasize data that can be 
collected from the electronic health record, radiographs obtained as part of routine clinical care, and assessments 
that can be completed over the telephone as needed.   
 
 
6.1 Baseline Assessments and Procedures: Hospital Presentation to Randomization (Day 1) 
• Inclusion/exclusion criteria screening 
• Pregnancy test (if applicable) 
• Informed consent 
• Completion of COVID Ordinal Outcomes Scale 
• Blood collection for CD4+ and CD8+ T cell cytokine expression 
• Nasal Swab testing for SARS-CoV-2  
• Completion of the Sequential Organ Failure Assessment (SOFA)33  
• Evaluation of Acute Respiratory Distress Syndrome (ARDS) by Berlin Criteria33 
• Baseline Variable Data Collection: 
o Hospital admissions data: date/time of presentation, origin (home, skilled nursing facility, 
rehabilitation/LTACH, nursing home, outside hospital, outside ICU), location at enrollment (ED, 
hospital ward, ICU 
o Demographics (age, sex, race, ethnicity, height, weight) 
o Signs and symptoms/onset date including acute signs/symptoms such as altered mental status, acute 
hypoxemic respiratory failure, liver function tests, renal function, coagulation studies, SOC chest 
imaging results 
o Concomitant Medications/Medication History to include: 
 
Chronic use of medications such as: corticosteroids, ACE inhibitors, angiotensin receptor 
blockers, non-steroids or anti-inflammatory drugs 
 
Open label antivirals received such as remdesivir 
 
Open label immunomodulators   
 
Biologic therapy such a convalescent plasma 
o Comorbidities 
o Oxygen/ventilation assessment including S/F ratio, ventilation type, & vasopressor use (if applicable) 
o Vital signs, including highest respiratory rate, lowest systolic blood pressure, and highest heart rate in 
the 12 hours prior to enrollment (if available) 
• 
Enrollment/Randomization  
• 
First study drug administration 

 
Version 1.0 
March 13, 2021 
 
Page 14 of 32 
 
6.2 Study Assessments/Procedures: Randomization to Hospital Discharge (Daily) 
• Study Variable Data Collection 
o Medication Assessment  
o Assess for clinical diagnosis of deep vein thrombosis (DVT) or pulmonary embolism (PE)  
o Oxygen/Ventilation assessment including S/F ratio, ventilation type, & vasopressor use (if applicable)  
o ARDS Assessment by Berlin Diagnostic Criteria (if applicable) 
o ICU admission/discharge information (if applicable)  
o Death date (if applicable) 
o Safety Outcomes: Dehydration, Seizure, Atrial or ventricular arrhythmia, Cardiac arrest, 
Symptomatic Hypotension, Acute kidney injury, Receipt of renal replacement therapy, Symptomatic 
hypoglycemia 
o Hospital discharge including patient destination at discharge 
 
6.2.1 Day Specific Assessments: Randomization to Hospital Discharge  
6.2.1.1 Days 2-7 (Daily) 
• COVID Ordinal Outcomes Scale  
• Study Drug Adherence Assessment (days 1-6) 
• Assessment of Antibiotic Use including azithromycin 
 
6.2.1.2 Day 3 
• Completion of SOFA assessment 
• Nasal swab for SARS CoV-2 testing 
 
6.2.1.3 Day 7 
• 
Blood collection for CD4+ and CD8+ T cell cytokine expression 
 
6.3 Assessments following Hospital Discharge 
6.3.1 Acute Care Follow-up 
For participants discharged from the study hospital prior to the Day 7 or Day 29 assessment, we will perform 
these assessments via telephone follow-up.  The Day 7 call window will be Day 7 through day14. The Day 29 call 
window will be Day 29 through day 36.  During these telephone calls, we will interview the patient, LAR, or 
facility staff to assess: 
• Date of death (if applicable) 
• ED visits, hospital readmissions, and use of supplemental oxygen after hospital discharge 
• Non-laboratory safety outcomes after hospital discharge and adverse events 
• Symptoms of acute respiratory infection 
• COVID Ordinal Outcomes Scale 
 
6.3.2 Long-term Follow-up 
We will follow-up selected patients at 3months to assess vital status, cognition, basic and instrumental activities 
of daily living, quality of life, employment status, physical disability, and psychological distress (i.e., depression, 
post-traumatic stress disorder, etc.), place of residence, and rehospitalizations. These assessments may occur by 
phone, in-person, or videoconferencing. 
 
 

 
Version 1.0 
March 13, 2021 
 
Page 15 of 32 
7. STATISTICAL CONSIDERATIONS 
 
7.1 Statistical Approach 
The primary analysis will be an intention-to-treat comparison of the Day 7 COVID Ordinal Outcome score 
between patients randomized to magnesium citrate plus a the probiotic Floranex versus placebo.  This analysis 
will be conducted with a proportional odds model using the Day 7 COVID Ordinal Outcome score as the 
dependent variable, randomized group assignment as the primary independent variable, and the following co-
variables: age, sex, baseline COVID Ordinal Outcome score, baseline SOFA score, and duration of acute 
respiratory infection symptoms prior to randomization.  An odds ratio >1.0 indicates more favorable outcomes 
with magnesium citrate plus  the probiotic Floranex on the COVID Ordinal Outcome scale, while an odds ratio 
<1.0 indicates more favorable outcomes with placebo.  
In additional to reporting data for the full trial population we will also report data separately for patients 
randomized in the ICU (who tend to be more severely ill) and those randomized outside the ICU (who tend to be 
less severely ill) as well as those with duration of symptoms ≤5 days prior to randomization and those with >5 
days of symptoms prior to randomization.  
The anticipated study size is 30 patients. We calculated the sample size under the assumption that we would have 
an interim analysis after approximately each 10 patients. We calculated the standard error of the log(odds-ratio) 
statistic with 15 patients per arm based on data from a recently completed trial within the PETAL Network that 
enrolled patients early in the course of critical illness, the Vitamin D to Improve Outcomes by Leveraging Early 
Treatment (VIOLET) trial.35 In the VIOLET trial at Day 15, 11.5% of patients had died, 5.8% were on invasive 
mechanical ventilation, 22.9% remained in the hospital, and the remaining had been discharged from the hospital 
(Table 1). We used these outcomes in VIOLET to approximate Day 7 outcomes on the COVID Ordinal Outcome 
scale that we may observe in this trial.   
 
Table 1. Patient status 14 days (“Day 15”) after randomization in the VIOLET trial.35 
Patient Status 
Percentage of patients 
Deceased 
11.5% 
Invasive mechanical ventilation 
5.8% 
Hospitalized, not on invasive mechanical ventilation 
21.9% 
Discharged from the hospital 
60.8% 
 
We plan to use a Bayesian analysis of the evolving data which allows flexibility in the number and timing of the 
interim analyses.  If we determine there is >95% probability of the odds ratio being >1.0, the DSMB should 
consider stopping the trial for efficacy. If we determine there is >90% probability that the odds ratio is <1.1, the 
DSMB should consider stopping the trial for futility. If we determine there is >70% probability that the odds ratio 
is <0.70, the DSMB should consider stopping the trial for harm. We will use a prior odds ratio of 1.0 (equal 
chance of harm and benefit; mean log OR of 0.0) and a prior distribution of the standard error for its log set at 
0.352 for tests of efficacy and a non-informative prior for tests of futility and harm. The results will be reported in 
a similar manner to those published by Goligher et al.36    One advantage of Bayesian analysis is that stopping 
guidelines are not binding and the DSMB is charged with using judgement and data both internal and external to 
the trial to make any irrevocable decision. 
 
If the trial enrolls 30 participants, further enrollment will be paused until the DSMB reviews data on the primary 
outcome from all enrolled participants; a decision to continue enrollment will be made by the DSMB while the 
investigators remain blinded.   
 
Stopping points:   
We will conduct a futility analysis at 20 patients.  If no efficacy is observed or the primary endpoint 
indicates worse outcomes, the study will be halted. 
 

 
Version 1.0 
March 13, 2021 
 
Page 16 of 32 
7.2 Planned deviations from this design 
This trial is being conducted in a rapidly evolving pandemic of a novel disease.  Thus, we have developed a 
statistical plan with flexibility to be modified based on results from other concurrently conducted trials and 
emerging data on the clinical epidemiology of COVID-19.  The primary advantage of a Bayesian monitoring plan 
is that whenever the trial is stopped the inference only depends on the data and not the original statistical plan that 
was developed at a time when less was known about COVID-19 and potentially effective treatments.  
 
 
8. DATA QUALITY MONITORING AND STORAGE 
 
8.1 Data Quality Monitoring 
Data quality will be reviewed remotely using front-end range and logic checks at the time of data entry and back-
end monitoring of data using application programming interface tools connecting the online database to statistical 
software to generate data reports. Patient records and case report forms will also be examined by site personnel 
for a randomly selected 5-10% sample to evaluate the accuracy and completeness of the data entered into the 
database and monitor for protocol compliance.  The coordinating center will perform remote monitoring of each 
study site to examine the completeness and accuracy of informed consent documents for study participants, 
documentation of eligibility criteria, and the completeness of study outcome collection. 
 
8.2 Data Storage  
Data will be entered into a secure online database.  All data will be maintained in the secure online database until 
the time of study publication.  At the time of publication, a de-identified version of the database will be generated. 
 
 
9. RISK ASSESSMENT 
 
9.1 Potential Risk to Participants 
Although both magnesium citrate and the probiotic Floranexs are FDA approved medications with an established 
safety profile, potential risks exist to participating in this study of magnesium citrate plus  the probiotic Floranex 
versus placebo for the treatment of COVID-19.  Mild hypermagnesemia (increases of >1meq) are typical because 
the majority of the medication remains intraluminal.   Patients with renal insufficiency (<30cc/min) are at risk for 
greater increases in systemic magnesium levels and thus they will be excluded from study participation.  Below, 
we outline side effects based on serum magnesium levels. 
 
9.1.1 Potential risks of receiving magnesium citrate 
Common Side effects of magnesium citrate include: 
Abdominal cramping 
Diarrhea 
Electrolyte imbalance 
Gas (flatulence) 
Nausea 
Vomiting 
Hypermagnesemia (high levels of magnesium in the blood.  
 
Side effects that can occur with Hypermagnesemia: 
Nervous system 
• 
Muscle weakness, decrease in tendon reflexes, mental confusion, or sedation when serum magnesium (Mg) 
levels increase to 4 to 7 mEq/L,  
• 
Slowed respiratory rate and hypotension when serum magnesium (Mg) levels increase to 5 to 10 mEq/L  

 
Version 1.0 
March 13, 2021 
 
Page 17 of 32 
• 
Profound mental depression, areflexia, coma and respiratory paralysis when serum Mg levels increase to 10 to 
15 mEq/L  
• 
Death possible when serum Mg levels rise to 15 mEq/L or higher. 
 
Cardiovascular 
• 
Hypotension may be observed when serum Mg levels rise to 5 to 10 mEq/L.  
• 
Hypotension, depressed myocardial conductivity, and bradyarrhythmias may be associated with levels greater 
than 10 mEq/L.  
• 
Asystole when levels rise to 25 mEq/L.  
 
Metabolic 
• 
Hypocalcemia  
 
Gastrointestinal 
• 
Nausea when serum Mg levels rise to 4 to 5 mEq/L. 
• 
Rare cases of paralytic ileus associated with serum Mg levels greater than 5 mEq/L have been reported. 
• 
 
9.1.2 Potential risks of receiving the probiotic Floranexs  
 
Risks include is gas, bloating and diarrhea. 
 
9.1.3 Potential risks of receiving placebo with COVID-19 
One potential risk to participating in this study is receiving placebo rather than magnesium citrate plus the 
probiotic Floranex.  This risk is only relevant if magnesium citrate plus a the probiotic Floranex is ultimately 
found to be an effective therapy for COVID-19 and is not relevant if magnesium citrate plus the probiotic 
Floranex is ultimately found to be an ineffective therapy for COVID-19.  This trial protocol minimizes this risk 
through rigorous design to minimize the number of patients who must be enrolled to determine whether 
magnesium citrate plus the probiotic Floranex is an effective therapy for COVID-19, excluding patients who 
decline to participate because they feel their optimal care requires magnesium citrate plus the probiotic Floranex, 
excluding patients whose treating clinicians declines to allow enrollment because they feel the patient’s optimal 
care requires treatment with magnesium citrate plus  the probiotic Floranex, and specifying procedures for 
stopping the study drug, unblinding, and allowing open-label administration of magnesium citrate plus the 
probiotic Floranex for patients who experience clinical deterioration during the study period. 
 
9.2 Minimization of Risk 
Federal regulations at 45 CFR 46.111(a)(1) require that risks to participants are minimized by using procedures 
which are consistent with sound research design.  This trial protocol incorporates numerous design elements to 
minimize risk to patients that meet this human subject protection requirement.  Magnesium citrate has been 
approved by the Food and Drug Administration and has been used in clinical practice for decades in a number of 
patient populations with an established safety profile.  The dose and route of administration of magnesium citrate 
and the probiotic Floranexs in this trial are comparable to the dose and route of administration approved for uses 
already approved by the FDA. The trial protocol includes on-study monitoring to minimize the risk to patients 
during therapy.  This monitoring also includes both automated electronic health record and manual study 
personnel review for medications with potential interactions with magnesium citrate and the probiotic Floranexs. 
The trial protocol includes monitoring of adverse events, clinical outcomes, and interim analyses by an 
independent data and safety monitoring board empowered to stop or modify the trial at any time.   
 

 
Version 1.0 
March 13, 2021 
 
Page 18 of 32 
9.3 Potential Benefit 
Study participants may or may not receive any direct benefits from their participation in this study. 
Administration of magnesium citrate plus the probiotic Floranex may improve clinical outcomes among adults 
hospitalized for COVID-19 infection. 
 
9.4 Risk in Relation to Anticipated Benefit 
Federal regulations at 45 CFR 46.111 (a)(2) require that “the risks to subjects are reasonable in relation to 
anticipated benefits, if any, to subjects, and the importance of the knowledge that may reasonably be expected to 
result.” Based on the preceding assessment of risks and potential benefits, the risks to subjects are reasonable in 
relation to anticipated benefits.   
 
 
10. HUMAN SUBJECTS PROTECTIONS 
Each study participant or a LAR must sign and date an informed consent form. Approval of the central 
institutional review board will be required before any participant is entered into the study.  
 
10.1 Selection of Subjects 
Federal regulations at 45 CFR 46(a)(3) require the equitable selection of subjects. The Vanderbilt University 
Medical Center emergency departments, hospital wards, and ICUs will be screened to determine if any patient 
meets inclusion and exclusion criteria. Data that have been collected as part of the routine clinical care of the 
patient will be reviewed to determine eligibility. If any patient meets criteria for study enrollment, then the 
attending physician responsible for his or her care will be asked for permission to approach the patient or his or 
her LAR for informed consent. Study exclusion criteria neither unjustly exclude classes of individuals from 
participation in the research nor unjustly include classes of individuals for participation in the research. Hence, the 
recruitment of participants conforms to the principle of distributive justice. 
 
10.2 Justification of Including Vulnerable Subjects 
The present research aims to investigate the safety and efficacy of magnesium citrate plus  the probiotic Floranex 
for the treatment of patients with COVID-19 who are at high risk for respiratory failure and mortality. Due to the 
nature of this patient population, many of these patients will have impaired decision-making capabilities. 
Moreover, those with intact decision-making capacities probably have milder disease than those with impaired 
capacity. Therefore, the validity of the study and its generalizability to severely ill patients would be 
compromised by enrolling only those participants with retained decision-making capacity. Hence, participants 
recruited for this trial are not being unfairly burdened with involvement in this research. 
 
10.3 Informed Consent 
Federal regulations 45 CFR 46.111(a)(5) require that informed consent will be sought from each patient or the 
patient’s LAR. Study personnel obtaining informed consent are responsible for ensuring that the patient or LAR 
understands the risks and benefits of participating in the study, answering any questions the patient or LAR may 
have throughout the study and sharing any new information in a timely manner that may be relevant to the 
patient’s or LAR’s willingness to permit the patient’s continued participation in the trial. The study personnel 
obtaining informed consent will make every effort to minimize coercion. All patients or their LARs will be 
informed of the objectives of the study and the potential risks. The informed consent document will be used to 
explain the risks and benefits of study participation to the patient or LAR in simple terms before the patient is 
entered into the study, and to confirm that the patient or LAR is satisfied with his or her understanding of the risks 
and benefits of participating in the study and desires to participate in the study. The investigator is responsible for 
ensuring that informed consent is given by each patient or LAR. This includes obtaining the appropriate 
signatures and dates on the informed consent document prior to the performance of any protocol procedures 
including administration of study agent. 
For additional details, see Section 3. 

 
Version 1.0 
March 13, 2021 
 
Page 19 of 32 
 
10.4 Continuing Consent 
Patients for whom consent was initially obtained from a LAR, but who subsequently regain decision-making 
capacity while in hospital will be approached for consent for continuing participation, including continuance of 
data acquisition. The consent form signed by the LAR should reflect that such consent should be obtained.  The 
process for obtaining consent from these patients will be the same as that outlined in section 3. 
 
10.5 Withdrawal of Consent 
Participating patients may withdraw or be withdrawn (by the LAR, treating physician, or investigator) from the 
trial at any time without prejudice. Data recorded up to the point of withdrawal will be included in the trial 
analysis, unless consent to use data has also been withdrawn. Withdrawal of consent prior to receipt of study drug 
will constitute a screen-failure and will be recorded.  Withdrawal of consent after randomization and 
administration of one or more doses of study drug will lead to discontinuation of study interventions but site staff 
will request access to medical records for data related to the trial.   
 
10.6 Identification of Legally Authorized Representatives 
Many of the patients approached for participation in this research protocol will have impaired decision-making 
capacity due to critical illness and will not be able to provide informed consent. Accordingly, informed consent 
will be sought from the patient’s LAR.   
Regarding consent from the LAR, the existing federal research regulations (‘the Common Rule’) states at 45 CFR 
46.116 that “no investigator may involve a human being as a subject in research…unless the investigator has 
obtained the legally effective informed consent of the subject or the subject’s legally authorized representative”; 
and defines at 45 CFR 46 102 (c) a LAR as “an individual or judicial or other body authorized under applicable 
law to consent on behalf of a prospective subject to the subject’s participation in the procedures(s) involved in the 
research.” The Office of Human Research Protections (OHRP) defined examples of “applicable law” as being 
state statutes, regulations, case law, or formal opinion of a State Attorney General that addresses the issue of 
surrogate consent to medical procedures. Such “applicable law” could then be considered as empowering the LAR 
to provide consent for participant participation in the research. Interpretation of “applicable law” may be state 
specific and will be addressed by the central IRB.  
According to a previous President’s Bioethics Committee (National Bioethics Advisory Committee (NBAC)), an 
investigator should accept a relative or friend of the potential participant who is recognized as an LAR for 
purposes of clinical decision making under the law of the state where the research takes place.46 Finally, OHRP 
has stated in their determination letters that a surrogate could serve as a LAR for research decision making if such 
an individual is authorized under applicable state law to provide consent for the “procedures” involved in the 
research study 
 
10.7 Justification of Surrogate Consent 
According to the Belmont Report, respect for persons incorporates at least two ethical convictions; first, that 
individuals should be treated as autonomous agents, and second, that persons with diminished autonomy are 
entitled to protection. One method that serves to protect patients is restrictions on the participation of patients in 
research that presents greater than minimal risk. Commentators and research ethics commissions have held the 
view that it is permissible to include incapable participants in greater than minimal risk research as long as there is 
the potential for beneficial effects and that the research presents a balance of risks and expected direct benefits 
similar to that available in the clinical setting.47 Several U.S. task forces have deemed it permissible to include 
incapable participants in research. For example, the American College of Physicians’ document allows surrogates 
to consent to research involving incapable participants only “if the net additional risks of participation are not 
substantially greater than the risks of standard treatment”.48 Finally, NBAC stated that an IRB may approve a 
protocol that presents greater than minimal risk but offers the prospect of direct medical benefits to the 
participant, provided that “the potential subject’s LAR gives permission…”.46 

 
Version 1.0 
March 13, 2021 
 
Page 20 of 32 
Consistent with the above ethical sensibilities regarding the participation of decisionally incapable participant in 
research and the previous assessment of risks and benefits in the previous section, the present trial presents a 
balance of risks and potential direct benefits that is similar to that available in the clinical setting. 
 
10.8 Additional Safeguards for Vulnerable Participants 
The present research will involve participants who might be vulnerable to coercion or undue influence. As 
required in 45CFR46.111(b), we recommend that sites utilize additional safeguards to protect the rights and 
welfare of these participants. Such safeguards might include but are not limited to: a) assessment of the potential 
participant’s capacity to provide informed consent, and b) the availability of the LAR to monitor the participant’s 
subsequent participation and withdrawal from the study. The specific nature of the additional safeguards will be 
left to the discretion of the central IRB, in conjunction with the sites. 
 
10.9 Confidentiality 
Federal regulations at 45 CFR 46 111 (a) (7) requires that when appropriate, there are adequate provisions to 
protect the privacy of participants and to maintain the confidentiality of data. At no time during the course of this 
study, its analysis, or its publication will patient identities be revealed in any manner.  The minimum necessary 
data containing patient or provider identities will be collected.  All patients will be assigned a unique study ID 
number for tracking.  All data collected for this study will be entered directly into a secure online database.  All 
data will be maintained in the secure online database until the time of study publication.  At the time of 
publication, a de-identified version of the database will be generated. Further, tools within the secure online 
database will be used so that only the coordinating center and investigators from the enrolling site will have 
access to data from participants enrolled at that site. 
 
 
11. ADVERSE EVENTS 
Assuring patient safety is an essential component of this protocol.  Magnesium citrate has been approved by the 
Food and Drug Administration and used in clinical practice for decades with an established safety profile.  Use of 
magnesium citrate plus  the probiotic Floranex for the treatment of acute respiratory infection due to COVID-19, 
however, raises unique safety considerations.  This protocol addresses these considerations through: 
1. Exclusion criteria designed to prevent enrollment of patients likely to experience adverse events with receipt 
of magnesium citrate or the probiotic Floranexs, such as those with creatinine clearance of <30cc/min; 
2. Proactive education of treating clinicians regarding medication interactions relevant to use of magnesium 
citrate plus  the probiotic Floranex in the inpatient setting; 
3. On-study monitoring of co-interventions (e.g., medications) and patient characteristics (e.g., EKG) to 
intervene before adverse events occur; 
4. Systematic collection of safety outcomes relevant to use of magnesium citrate plus  the probiotic Floranex in 
this setting; 
5. Structured reporting of adverse events 
 
11.1 Adverse Event Definitions 
Adverse Event: Any untoward medical occurrence associated with the use of a drug or a study procedure, 
whether or not considered drug related. 
Serious Adverse Event: A serious adverse event is any adverse event that results in one of the outcomes listed in 
section 11.3 below.  
Adverse Reaction: An adverse reaction means any adverse event caused by a study intervention. An adverse 
reaction is a subset of all suspected adverse events where there is a reason to conclude that the study intervention 
caused the event.  
Suspected Adverse Reaction: Any adverse event for which there is a reasonable possibility that the study 
procedures caused the adverse event. Reasonable possibility means there is evidence to suggest a causal 

 
Version 1.0 
March 13, 2021 
 
Page 21 of 32 
relationship between the study procedures and the adverse event. A suspected adverse reaction implies a lesser 
degree of certainty about causality than adverse reaction.  
Suspected Unexpected Serious Adverse Reaction (SUSAR): An adverse reaction that is both unexpected (not 
consistent with risks outlined in the study protocol or investigator brochure), serious, and meets the definition of a 
suspected adverse reaction. 
 
11.2 Safety Monitoring 
Assuring patient safety is an essential component of this protocol. Each participating investigator has primary 
responsibility for the safety of the individual participants under his or her care. The Investigators will determine 
daily if any adverse events occur during the period from enrollment through study day 7 or hospital discharge, 
whichever occurs first and will determine if such adverse events are reportable.  Thereafter, adverse events are not 
required to be reported unless the investigator feels the adverse event was related to study drug or study 
procedures.   
The following adverse events will be considered reportable and thus collected in the adverse event case report 
forms: 
 
• 
Serious adverse events 
• 
Non-serious adverse events that are considered by the investigator to be related to study procedures or 
of uncertain relationship (Appendix C) 
• 
Events leading to permanent discontinuation of study drug 
Study-specific clinical outcomes (Primary, Secondary and Safety Outcomes and Assessments During the 
Study), including serious outcomes such as organ failures and death, are systematically recorded in the 
case report forms and are exempt from adverse event reporting unless the investigator deems the event to 
be related to the administration of study drug or the conduct of study procedures (or of uncertain 
relationship) as outlined in Appendix C.  
 
After randomization, adverse events must be evaluated by the investigator. If the adverse event is judged to be 
reportable, as outlined above, then the investigator will report to the Clinical Coordinating Center (CCC) their 
assessment of the potential relatedness of each adverse event to the study drug or protocol procedure via 
electronic data entry. Investigators will assess if there is a reasonable possibility that the study procedure caused 
the event, based on the criteria outlined in Appendix C. Investigators will also consider if the event is unexpected.  
Unexpected adverse events are events not listed in the study protocol and the package insert for the study drugs 
will also determine if adverse events are unanticipated given the patient’s clinical course, previous medical 
conditions, and concomitant medications.   
If a patient's treatment is discontinued as a result of an adverse event, study site personnel must also report the 
circumstances and data leading to discontinuation of treatment in the adverse event case report forms.   
 
11.3 Serious Adverse Events 
Serious adverse event collection begins after randomization and study procedures have been initiated.  If a patient 
experiences a serious adverse event after consent, but prior to randomization or starting study procedures, the 
event will NOT be collected. Study site personnel must alert the CCC of any serious and study procedure 
related adverse event within 24 hours of investigator awareness of the event.  Alerts issued via telephone are to 
be immediately followed with official notification on the adverse event case report form. See Appendix C for 
reporting timelines for serious, unexpected, study related events (SAEs) and serious, unexpected suspected 
adverse reactions (SUSARs) 
As per the FDA and NIH definitions, a serious adverse event is any adverse event that results in one of the 
following outcomes: 
 Death 
 A life-threatening experience (that is, immediate risk of dying) 
 Prolonged inpatient hospitalization or re-hospitalization 

 
Version 1.0 
March 13, 2021 
 
Page 22 of 32 
As per http://www.fda.gov/Safety/MedWatch/HowToReport/ucm053087.htm: Report if admission to the 
hospital or prolongation of hospitalization was a result of the adverse event. Emergency room visits that do 
not result in admission to the hospital should be evaluated for one of the other serious outcomes (e.g., life-
threatening; required intervention to prevent permanent impairment or damage; other serious medically 
important event). 
 Persistent or significant disability/incapacity 
As per http://www.fda.gov/Safety/MedWatch/HowToReport/ucm053087.htm: Report if the adverse event 
resulted in a substantial disruption of a person's ability to conduct normal life functions, i.e., the adverse 
event resulted in a significant, persistent or permanent change, impairment, damage or disruption in the 
patient's body function/structure, physical activities and/or quality of life. 
 
Reportable serious adverse events that may not result in death, be life-threatening, or require hospitalization may 
be considered serious adverse events when, based upon appropriate medical judgment, they may jeopardize the 
patient and may require medical or surgical intervention to prevent one of the outcomes listed in this definition. 
Serious adverse events will be collected until hospital discharge, regardless of the investigator's opinion of 
causation.  
 
 
12. DATA AND SAFETY MONITORING BOARD (DSMB) 
The principal role of the DSMB is to assure the safety of participants in the trial. They will regularly monitor data 
from this trial, review and assess the performance of its operations, and make recommendations to the steering 
committee with respect to:  
• 
Review of adverse events 
• 
Interim results of the study for evidence of efficacy or adverse events 
• 
Possible early termination of the trial because of new external information, early attainment of study 
objectives, safety concerns, or inadequate performance 
• 
Possible modifications in the clinical trial protocol  
• 
Performance of individual centers  
 
 

 
Version 1.0 
March 13, 2021 
 
Page 23 of 32 
REFERENCES 
 
1.  
Del Rio C, Malani PN. COVID-19-New Insights on a Rapidly Changing Epidemic. JAMA 2020; 
2.  
Fauci AS, Lane HC, Redfield RR. Covid-19 - Navigating the Uncharted. N Engl J Med 2020; 
3.  
Cao B, Wang Y, Wen D, et al. A Trial of Lopinavir-Ritonavir in Adults Hospitalized with Severe Covid-19. 
N Engl J Med 2020; 
4.  
Wang M, Cao R, Zhang L, et al. Remdesivir and chloroquine effectively inhibit the recently emerged novel 
coronavirus (2019-nCoV) in vitro. Cell Res 2020;30(3):269–71.  
5.  
Yao X, Ye F, Zhang M, et al. In Vitro Antiviral Activity and Projection of Optimized Dosing Design of 
Magnesium citrate for the Treatment of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). 
Clin Infect Dis Off Publ Infect Dis Soc Am 2020; 
6.  
World Health Organization (WHO). WHO R&D Blueprint: informal consultation on prioritization of 
candidate therapeutic agents for use in novel coronavirus 2019 infection, Geneva, Switzerland, 24 January 
2020. [Internet]. [cited 2020 Mar 19];Available from: https://apps.who.int/iris/handle/10665/330680 
7.  
Li Q, Guan X, Wu P, et al. Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus-Infected 
Pneumonia. N Engl J Med 2020; 
8.  
Zhu N, Zhang D, Wang W, et al. A Novel Coronavirus from Patients with Pneumonia in China, 2019. N 
Engl J Med 2020;382(8):727–33.  
9.  
Perlman S. Another Decade, Another Coronavirus. N Engl J Med 2020;382(8):760–2.  
10.  Su S, Wong G, Shi W, et al. Epidemiology, Genetic Recombination, and Pathogenesis of Coronaviruses. 
Trends Microbiol 2016;24(6):490–502.  
11.  Cui J, Li F, Shi Z-L. Origin and evolution of pathogenic coronaviruses. Nat Rev Microbiol 2019;17(3):181–
92.  
12.  Discovery of a novel coronavirus associated with the recent pneumonia outbreak in humans and its potential 
bat origin | bioRxiv [Internet]. [cited 2020 Mar 18];Available from: https://www-biorxiv-
org.proxy.library.vanderbilt.edu/content/10.1101/2020.01.22.914952v2.abstract 
13.  Cheng PK, Wong DA, Tong LK, et al. Viral shedding patterns of coronavirus in patients with probable 
severe acute respiratory syndrome. The Lancet 2004;363(9422):1699–700.  
14.  Hui DS, Azhar EI, Kim Y-J, Memish ZA, Oh M, Zumla A. Middle East respiratory syndrome coronavirus: 
risk factors and determinants of primary, household, and nosocomial transmission. Lancet Infect Dis 
2018;18(8):e217–27.  
15.  Wang Y, Liu Y, Liu L, Xang X, Luo N, Ling L. Clinical outcome of 55 asymptomatic cases at the time of 
hospital admission infected with SARS-Coronavirus-2 in Shenzhen, China. J Infect Dis 2020; 
16.  Wu C, Chen X, Cai Y, et al. Risk Factors Associated With Acute Respiratory Distress Syndrome and Death 
in Patients With Coronavirus Disease 2019 Pneumonia in Wuhan, China. JAMA Intern Med 2020; 
17.  Arentz M, Yim E, Klaff L, et al. Characteristics and Outcomes of 21 Critically Ill Patients With COVID-19 
in Washington State. JAMA [Internet] 2020 [cited 2020 Mar 19];(Publised Online). Available from: 
https://jamanetwork-com.proxy.library.vanderbilt.edu/journals/jama/fullarticle/2763485 
18.  Wilson N, Kvalsig A, Telfar-Barnard L, Baker M. Case-fatality estimates for COVID-19 calculated by 
using a lag time for fatality. Emerg Infect Dis [Internet] 2020 [cited 2020 Mar 18];26(6). Available from: 
https://wwwnc.cdc.gov/eid/article/26/6/20-0320_article 
19.  DrugBank. Magnesium citrate. [Internet]. [cited 2020 Mar 19];Available from: 
https://www.drugbank.ca/drugs/DB01611 
20.  Al-Bari MAA. Targeting endosomal acidification by chloroquine analogs as a promising strategy for the 
treatment of emerging viral diseases. Pharmacol Res Perspect 2017;5(1):e00293.  
21.  Liu J, Cao R, Xu M, et al. Magnesium citrate, a less toxic derivative of chloroquine, is effective in inhibiting 
SARS-CoV-2 infection in vitro. Cell Discov 2020;6(1):1–4.  
22.  Colson P, Rolain J-M, Lagier J-C, Brouqui P, Raoult D. Chloroquine and magnesium citrate as available 
weapons to fight COVID-19. Int J Antimicrob Agents 2020;105932.  
23.  Lauer SA, Grantz KH, Bi Q, et al. The Incubation Period of Coronavirus Disease 2019 (COVID-19) From 
Publicly Reported Confirmed Cases: Estimation and Application. Ann Intern Med [Internet] 2020 [cited 

 
Version 1.0 
March 13, 2021 
 
Page 24 of 32 
2020 Mar 19];Available from: https://annals.org/aim/fullarticle/2762808/incubation-period-coronavirus-
disease-2019-covid-19-from-publicly-reported 
24.  Wang D, Hu B, Hu C, et al. Clinical Characteristics of 138 Hospitalized Patients With 2019 Novel 
Coronavirus–Infected Pneumonia in Wuhan, China. JAMA 2020;323(11):1061–9.  
25.  Cao J, Hu X, Cheng W, Yu L, Tu W-J, Liu Q. Clinical features and short-term outcomes of 18 patients with 
corona virus disease 2019 in intensive care unit. Intensive Care Med [Internet] 2020 [cited 2020 Mar 
20];Available from: https://doi.org/10.1007/s00134-020-05987-7 
26.  Baden L, Rubin E. Covid-19 — The Search for Effective Therapy. NEJM [Internet] 2020 [cited 2020 Mar 
19];Published Online. Available from: https://www-nejm-
org.proxy.library.vanderbilt.edu/doi/full/10.1056/NEJMe2005477 
27.  Gao J, Tian Z, Yang X. Breakthrough: Chloroquine phosphate has shown apparent efficacy in treatment of 
COVID-19 associated pneumonia in clinical studies. Biosci Trends 2020;14(1):72–3.  
28.  Paton NI, Goodall RL, Dunn DT, et al. Effects of magnesium citrate on immune activation and disease 
progression among HIV-infected patients not receiving antiretroviral therapy: a randomized controlled trial. 
JAMA 2012;308(4):353–61.  
29.  Roques P, Thiberville S-D, Dupuis-Maguiraga L, et al. Paradoxical Effect of Chloroquine Treatment in 
Enhancing Chikungunya Virus Infection. Viruses 2018;10(5).  
30.  Guan W, Ni Z, Hu Y, et al. Clinical Characteristics of Coronavirus Disease 2019 in China. N Engl J Med 
2020;0(0):null.  
31.  Wang Y, Fan G, Salam A, et al. Comparative effectiveness of combined favipiravir and oseltamivir therapy 
versus oseltamivir monotherapy in critically ill patients with influenza virus infection. J Infect Dis 2019; 
32.  WHO | Coronavirus disease (COVID-2019) R&D [Internet]. WHO. [cited 2020 Mar 18];Available from: 
http://www.who.int/blueprint/priority-diseases/key-action/novel-coronavirus/en/ 
33.  ARDS Definition Task Force, Ranieri VM, Rubenfeld GD, et al. Acute respiratory distress syndrome: the 
Berlin Definition. JAMA 2012;307(23):2526–33.  
34.  Kidney Disease Improving Global Outcomes. KDIGO clinical practice guideline for acute kidney injury. 
Kidney Int 2012;2: Suppl:1–138.  
35.  National Heart, Lung, and Blood Institute PETAL Clinical Trials Network, Ginde AA, Brower RG, et al. 
Early High-Dose Vitamin D3 for Critically Ill, Vitamin D-Deficient Patients. N Engl J Med 2019; 
36.  Goligher EC, Tomlinson G, Hajage D, et al. Extracorporeal Membrane Oxygenation for Severe Acute 
Respiratory Distress Syndrome and Posterior Probability of Mortality Benefit in a Post Hoc Bayesian 
Analysis of a Randomized Clinical Trial. JAMA 2018;320(21):2251–9.  
37.  Schoenfeld DA, Hui Zheng, Finkelstein DM. Bayesian design using adult data to augment pediatric trials. 
Clin Trials Lond Engl 2009;6(4):297–304.  
38.  Felson DT, Anderson JJ, Meenan RF. The comparative efficacy and toxicity of second-line drugs in 
rheumatoid arthritis. Results of two metaanalyses. Arthritis Rheum 1990;33(10):1449–61.  
39.  Manzo C, Gareri P, Castagna A. Psychomotor Agitation Following Treatment with Magnesium citrate. Drug 
Saf - Case Rep 2017;4(1):6.  
40.  Gonzalez-Nieto JA, Costa-Juan E. Psychiatric symptoms induced by magnesium citrate. Lupus 
2015;24(3):339–40.  
41.  Joyce E, Fabre A, Mahon N. Magnesium citrate cardiotoxicity presenting as a rapidly evolving biventricular 
cardiomyopathy: key diagnostic features and literature review. Eur Heart J Acute Cardiovasc Care 
2013;2(1):77–83.  
42.  Magnesium citrate [Internet]. In: LiverTox: Clinical and Research Information on Drug-Induced Liver 
Injury. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012 [cited 2020 
Mar 21]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK548738/ 
43.  Cansu DU, Korkmaz C. Hypoglycaemia induced by magnesium citrate in a non-diabetic patient treated for 
RA. Rheumatol Oxf Engl 2008;47(3):378–9.  
44.  Pelle MT, Callen JP. Adverse cutaneous reactions to magnesium citrate are more common in patients with 
dermatomyositis than in patients with cutaneous lupus erythematosus. Arch Dermatol 2002;138(9):1231–3; 
discussion 1233.  

 
Version 1.0 
March 13, 2021 
 
Page 25 of 32 
45.  Sames E, Paterson H, Li C. Magnesium citrate-induced agranulocytosis in a patient with long-term 
rheumatoid arthritis. Eur J Rheumatol 2016;3(2):91–2.  
46.  National Bioethics Advisory Commitee (NBAC). Research Involving Persons with Mental Disorders That 
May Affect Decision making Capacity. U.S. Government Printing Office; 1998.  
47.  Dresser R. Research Involving Persons with Mental Disabilities: A Review of Policy Issues and Proposals. 
Rockville: U.S. Government Printing Office; 1998.  
48.  Cognitively impaired subjects. American College of Physicians. Ann Intern Med 1989;111(10):843–8.  
 
 
 
 

 
Version 1.0 
March 13, 2021 
 
Page 26 of 32 
APPENDICES  
 
Appendix A. Schedule of Events 
 
Study Activity 
Pre-
enroll
ment 
Day 
1 
Day 
2 
Day 
3 
Day 
4 
Day 
5 
Day 
6 
Day 
7 
Day 8 
through 
Discharge 
Day 
29 
Acute Care F/U 
(by phone if 
discharged prior to 
Day 7 or Day 29) 
3 Mos. 
F/U 
Eligibility assessment 
X 
 
 
 
 
 
 
 
 
 
 
 
Pregnancy test (if applicable) 
X 
 
 
 
 
 
 
 
 
 
 
 
Informed consent 
X 
 
 
 
 
 
 
 
 
 
 
 
COVID Ordinal Outcome Score Assessment1 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
 
Randomization 
 
X 
 
 
 
 
 
 
 
 
 
 
Baseline Variable Data Collection 
 
X 
 
 
 
 
 
 
 
 
 
 
Blood Sample Collection 
 
X 
 
 
 
 
 
X 
 
 
 
 
Nasal Swab Collection 
 
X 
 
X 
 
 
 
 
 
X 
 
 
Sequential Organ Failure Assessment (SOFA) 
 
X 
 
X 
 
 
 
 
 
 
 
 
ARDS Evaluation1 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
 
 
Study Drug Delivery 
 
X 
 
 
 
 
 
 
 
 
 
 
Study Variable Data Collection1 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
 
 
Assessment of Study Drug Adherence1 
 
X 
X 
X 
X 
X 
X 
 
 
 
 
 
Adverse Events Monitoring/Assessment   
 
X 
X 
X 
X 
X 
X 
X 
 
X 
X 
 
Safety Outcomes Assessment 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
 
 
Mortality Assessment 
 
 
 
 
 
 
 
X 
 
X 
X 
 
Long-term Outcomes2  
 
 
 
 
 
 
 
 
 
 
 
X 
 
1Assessed if patient remains hospitalized; assessed by telephone follow-up if participant has been discharged 
2Assessed in-person, by telephone or videophone.    
 
 
 
 
 
 

 
Version 1.0 
March 13, 2021 
 
Page 27 of 32 
Appendix B. Potential medication interactions with magnesium citrate 
 
Magnesium containing drugs can potentially lower drug levels of some medications. We will 
advise treating physicians to allow there be a 6-hour window between administration of these 
drugs and magnesium citrate. This should not restrict the enrollment of someone taking these 
drugs. Here is a list of drugs that can be affected by magnesium citrate: 
 
Demeclocycline 
Dolutegravir 
Doxycycline 
Eltrombopag 
Lymecycline 
Minocycline 
Oxytetracycline 
Potassium Phosphates, Intravenously 
Tetracycline 
Ciprofloxacin 
Deflazacort 
Fleroxacin 
Gemifloxacin 
Levofloxacin 
Moxifloxacin 
Norfloxacin 
Ofloxacin 
Penicillamine 
Sodium Phosphates, Intravenously 
Vitamin D 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
Version 1.0 
March 13, 2021 
 
Page 28 of 32 
Appendix C:  Adverse Event Reporting and Unanticipated Events 
 
As noted in section 11, investigators will report all “serious adverse events,” defined as adverse events 
that are serious and have a reasonable possibility that the event was due to a study drug or procedure (or 
of uncertain relatedness), to the CCC within 24 hours. The CCC will then notify the NHLBI and Central 
Institutional Review Board (cIRB).  
The Medical Monitor at the CCC will work collaboratively with the reporting investigator to determine if 
a serious adverse event has a reasonable possibility of having been caused by the study drug or study 
procedure, as outlined in 21 CFR 312.32(a)(1), and below. The Medical Monitor will be unblinded and 
will also determine if the event is unexpected for magnesium citrate or the probiotic Floranexs.  An 
adverse is considered “unexpected” if it is not listed in the investigator brochure or the study protocol (21 
CFR 312.32(a)). If a determination is made that a serious adverse event has a reasonable possibility of 
having been caused by a study procedure or the study drug, it will be classified as a suspected adverse 
reaction. If the suspected adverse reaction is unexpected, it will be classified as a serious unexpected 
suspected adverse reaction (SUSAR).  
The CCC will report all unexpected deaths, serious and treatment related adverse events, and SUSARs to 
the DSMB, NHLBI, and cIRB within 7 days after receipt of the report from a clinical site. A written 
report will be sent to the NHLBI, DSMB, FDA, and the cIRB within 15 calendar days. The DSMB will 
also review all reported adverse events and clinical outcomes during scheduled interim analyses. The 
CCC will distribute the written summary of the DSMB’s periodic review of reported adverse events to the 
cIRB in accordance with NIH guidelines (http://grants.nih.gov/grants/guide/notice-files/not99-107.html). 
The Medical Monitor will provide to Sandoz Pharmacovigilance any significant safety findings (without 
disclosing protected health information) during the conduct of the trial.  
 
C.1. Unanticipated Problems (UP) 
Investigators must also report Unanticipated Problems, regardless of severity, associated with study 
procedures within 24 hours. An unanticipated problem is defined as follows: any incident, experience, or 
outcome that meets all of the following criteria:  
• 
Unexpected, in terms of nature, severity, or frequency, given the research procedures that are 
described in the protocol-related documents, such as the IRB-approved research protocol and 
informed consent document; and the characteristics of the subject population being studied;  
• 
Related or possibly related to participation in the research, in this guidance document, possibly 
related means there is a reasonable possibility that the incident, experience, or outcome may have 
been caused by the procedures involved in the research;  
• 
Suggests that the research places subjects or others at a greater risk of harm (including physical, 
psychological, economic, or social harm) than was previously known or recognized.  
 
C.2. Determining Relationship of Adverse Events to Study Drug or Study Procedures 
Investigators will be asked to grade the strength of the relationship of an adverse event to study drug or 
study procedures as follows:  
• 
Definitely Related: The event follows: a) A reasonable, temporal sequence from a study 
procedure; and b) Cannot be explained by the known characteristics of the patient’s clinical state 
or other therapies; and c) Evaluation of the patient’s clinical state indicates to the investigator that 
the experience is definitely related to study procedures.  
• 
Probably or Possibly Related: The event should be assessed following the same criteria for 
“Definitely Associated”. If in the investigator’s opinion at least one or more of the criteria are not 
present, then “probably” or “possibly” associated should be selected.  

 
Version 1.0 
March 13, 2021 
 
Page 29 of 32 
• 
Probably Not Related: The event occurred while the patient was on the study but can reasonably 
be explained by the known characteristics of the patient’s clinical state or other therapies.  
• 
Definitely Not Related: The event is definitely produced by the patient’s clinical state or by other 
modes of therapy administered to the patient.  
• 
Uncertain Relationship: The event does not meet any of the criteria previously outlined.  
 
C.3. Clinical Outcomes that may be Exempt from Adverse Event Reporting 
Study-specific outcomes of acute respiratory infection, COVID-19, and critical illness will be 
systematically collected for all patients in both study group and are exempt from adverse event 
reporting unless the investigator considers the event to be Definitely or Possibly Related (or of an 
Uncertain Relationship) to the study drug or study procedures.  Examples of study-specific clinical 
outcomes include: 
• 
Death not related to the study procedures  
• 
Neurological events 
o Seizure 
• 
Cardiovascular events 
o Receipt of vasopressors 
o Atrial or ventricular arrhythmia 
o Cardiac arrest 
• 
Respiratory events 
o Hypoxemia requiring supplemental oxygen 
o Acute respiratory distress syndrome 
o Receipt of mechanical ventilation 
o Receipt of extra-corporeal membrane oxygenation 
• 
Gastrointestinal events 
o Elevation of aspartate aminotransferase or alanine aminotransferase 
o Acute pancreatitis 
• 
Renal events 
o Acute kidney injury 
o Receipt of renal replacement therapy 
• 
Endocrine events 
o Symptomatic hypoglycemia 
• 
Hematologic or coagulation events 
o Neutropenia, lymphopenia, anemia, or thrombocytopenia 
• 
Dermatologic events 
o Severe dermatologic reaction (e.g., Steven’s Johnson Syndrome) 
Note: A study-specific clinical outcome may also qualify as a reportable adverse event.  For example, a 
ventricular arrhythmia that the investigator considers Definitely or Possibly Related to the study drug 
would be both recorded as a study-specific clinical outcome and reported as a Serious and Definitely or 
Possibly Related Adverse Event. 
 
 
 
 
 
 

 
Version 1.0 
March 13, 2021 
 
Page 30 of 32 
C.4. Decision tree for determining if an adverse event is reportable 
 
Figure 1. Decision tree for determining if an adverse event is reportable 
 
 
 
Figure adapted from Ranieri VM, Thompson BT, Barie PS et al. Drotrecogin alfa (activated) in 
adults with septic shock. N Engl J Med. 2012 May 31;366 (22):2055-64. PMID: 22616830. 
 
 
 
 

 
Version 1.0 
March 13, 2021 
 
Page 31 of 32 
Appendix D. Public Readiness and Emergency Preparedness Act 
This study is being conducted to determine whether magnesium citrate plus a the probiotic Floranex can 
safely and effectively be used to mitigate, treat, or cure COVID-19 or limit the harm of the COVID-19 
pandemic in accordance with the Secretary of the Department of Health and Human Services’ (HHS’s) 
Declaration under the Public Readiness and Emergency Preparedness Act for medical 
countermeasures against COVID-19 (COVID-19 Declaration)  effective February 4, 2020.  The purpose 
of this study is to test if magnesium citrate plus a the probiotic Floranex results in clinical benefit in 
patients hospitalized with COVID- 19.   
Magnesium citrate has been approved by the FDA for other uses and its investigational use for COVID-
19 in this study has been exempted by the FDA from investigational new drug application requirements 
pursuant to 21 CFR 312.2(b)(1).  This study is conducted under a Research Project Cooperative 
Agreement with the National Heart, Lung, and Blood Institute. 
 
1. 
Simonovich, V.A., et al., A Randomized Trial of Convalescent Plasma in Covid-19 Severe 
Pneumonia. N Engl J Med, 2020. 
2. 
Beigel, J.H., et al., Remdesivir for the Treatment of Covid-19 - Final Report. N Engl J Med, 2020. 
383(19): p. 1813-1826. 
3. 
Ling, Y., et al., Persistence and clearance of viral RNA in 2019 novel coronavirus disease 
rehabilitation patients. Chin Med J (Engl), 2020. 133(9): p. 1039-1043. 
4. 
Clay, C., et al., Primary severe acute respiratory syndrome coronavirus infection limits 
replication but not lung inflammation upon homologous rechallenge. J Virol, 2012. 86(8): p. 
4234-44. 
5. 
Chandrashekar, A., et al., SARS-CoV-2 infection protects against rechallenge in rhesus 
macaques. Science, 2020. 369(6505): p. 812-817. 
6. 
Tilg, H., et al., The intestinal microbiota fuelling metabolic inflammation. Nat Rev Immunol, 
2020. 20(1): p. 40-54. 
7. 
Friedland, R.P. and B. Haribabu, The role for the metagenome in the pathogenesis of COVID-19. 
EBioMedicine, 2020. 61: p. 103019. 
8. 
Gu, S., et al., Alterations of the Gut Microbiota in Patients with COVID-19 or H1N1 Influenza. 
Clin Infect Dis, 2020. 
9. 
Klann, E., S. Rich, and V. Mai, Gut microbiota and COVID-19: A superfluous diagnostic 
biomarker or therapeutic target? Clin Infect Dis, 2020. 
10. 
Zuo, T., et al., Depicting SARS-CoV-2 faecal viral activity in association with gut microbiota 
composition in patients with COVID-19. Gut, 2020. 
11. 
Sencio, V., et al., Gut Dysbiosis during Influenza Contributes to Pulmonary Pneumococcal 
Superinfection through Altered Short-Chain Fatty Acid Production. Cell Rep, 2020. 30(9): p. 
2934-2947 e6. 
12. 
Abt, M.C., et al., Commensal bacteria calibrate the activation threshold of innate antiviral 
immunity. Immunity, 2012. 37(1): p. 158-70. 
13. 
Rosshart, S.P., et al., Wild Mouse Gut Microbiota Promotes Host Fitness and Improves Disease 
Resistance. Cell, 2017. 171(5): p. 1015-1028 e13. 
14. 
Budden, K.F., et al., Emerging pathogenic links between microbiota and the gut-lung axis. Nat 
Rev Microbiol, 2017. 15(1): p. 55-63. 
15. 
Thorburn, A.N., et al., Evidence that asthma is a developmental origin disease influenced by 
maternal diet and bacterial metabolites. Nat Commun, 2015. 6: p. 7320. 
16. 
Conte, L. and D.M. Toraldo, Targeting the gut-lung microbiota axis by means of a high-fibre diet 
and the probiotic Floranexs may have anti-inflammatory effects in COVID-19 infection. Ther 
Adv Respir Dis, 2020. 14: p. 1753466620937170.  
 

 
Version 1.0 
March 13, 2021 
 
Page 32 of 32 
 
Appendix E 
COVID Ordinal Outcome Scale 
 
Patient State 
 
 
Descriptor 
 
Score 
 
Uninfected 
 
 
Uninfected, no viral RNA detected 
 
 
 
0 
 
Ambulatory Mild Disease 
Asymptomatic, viral RNA detected 
 
Symptomatic, independent 
 
Symptomatic, assistance needed 
 
1 
 
2 
 
3 
Hospitalized Moderate Disease 
Hospitalized, no oxygen needed 
 
Hospitalized, oxygen by mask or nasal prongs 
 
4 
 
5 
Hospitalized Severe Disease 
Hospitalized, oxygen by NIV or high flow 
 
Intubation and mechanical ventilation, pO2/FiO2 ≥150 or SpO2/FiO2 ≥200 
 
Mechanical ventilation, pO2/FiO2 <150 (SpO2/FiO2 <200) or vasopressors 
 
Mechanical ventilation, pO2/FiO2 <150 and vasopressors, dialysis or ECMO 
 
6 
 
7 
 
8 
 
9 
Dead 
Dead 
10