Efficacy of Niclosamide vs Placebo in SARS-CoV-2 Respiratory Viral Clearance, Viral Shedding, and Duration of Symptoms Among Patients With Mild to Moderate COVID-19

This randomized clinical trial compares the efficacy of niclosamide vs placebo in respiratory clearance of SARS-CoV-2 among patients with mild to moderate COVID-19.


eMethods.
Twice daily, a list of COVID-19 positive patients was generated by the Tufts Medical Center lab and securely provided to the study team. Upon receiving the positive test notification, COVID-19 positive participants were approached and screened by a study team member. Following initial screening for eligibility, a Health Insurance Portability and Accountability Act of (HIPAA) compliant telehealth platform was used to conduct a remote Informed Consent (IC) visit with a study team physician investigator.
For this study involving participants with COVID-19 positivity, the following steps were performed while obtaining the remote IC via telehealth: • Purpose of the study and the potential risks/benefits of the use of the Investigational Agent (niclosamide) in the treatment of confirmed COVID-19 infection was discussed in detail • Opportunity to review the IC form prior to or during the discussion was provided. Adequate time for discussion between the physician investigators was given to each potential participant. • Availability and/or possibility of other potential treatment options were discussed.
• A second member of the study team was present during the entire IC discussion. The witness asked the potential participant if they understood the contents of the discussion and if they had any questions to address. The participant was informed that they could ask questions at any time during the trial. • The participant and physician investigator and witness signed the IC form via a secure Docusign account.
During the screening process, information on all concomitant therapies, medications, and procedures were recorded in the source documents along with the diagnosis or reason for use. Those therapies used for the treatment of an adverse event (AE) were linked to an AE and documentation of the AE completed. Focused medical history based on known risks for severe COVID infection were obtained along with smoking history, demographics and record of .positive COVID-19 result by PCR were obtained. Clinical data, AEs, concomitant medications, and any other data collected from participants was entered into a REDCap database with password protection and internal quality checks, such as automatic range checks, to identify data that appear inconsistent, incomplete, or inaccurate.
Participants who provided informed consent and met all of the inclusion and none of the exclusion criteria were randomized on treatment Day 0 in a 1:1 ratio to either the Treatment Group (niclosamide) or the Control Group (placebo), in accordance with a computer-generated schedule. Study personnel were instructed not to randomize until participant had been confirmed to meet all inclusion/exclusion criteria on treatment Day 0. Following randomization, the investigational pharmacy packaged and dispensed either niclosamide or placebo, dispensing the entire supply at one time. Participants in the Treatment Group received niclosamide 2 grams orally once daily for 7 days in addition to current standard of care treatment. Those in the Control Group received placebo by mouth in the same numbers of pills for 7 days in addition to current standard of care treatment. In addition to niclosamide or placebo, all enrolled participants were provided an oral thermometer and fingertip probe pulsoximeter with the specific instructions to monitor and record both temperature at oxygen saturation at the time of daily oral administration of drug. All study materials were delivered to participants via courier service.

Sample Size Calculation
For the primary efficacy endpoint of respiratory virologic clearance at Day 3 measured by oropharyngeal viral shedding, 40 participants in each group achieve 89.1% power to detect a difference between the group proportions of 35%. We assumed that 50% and 15% of participants in the niclosamide and placebo groups would have a negative test on Day 3. The calculation was under a two-sided Fisher's Exact Test and a significance level of 0.05. Fecal samples and oropharyngeal swab samples were collected for viral shedding as measured by PCR on days 1, 3, 7, 10, 14 and 21 (day 21 -fecal sample only). The collection of specimens was directly observed by a study team member via the telehealth platform educating the participant to open the viral transport kit and swab the back of the throat and tonsil area (avoiding mouth, teeth, and gums) and place to swab back into the viral media vial. For fecal specimens, the participant was instructed to swab feces from a plastic container (or wrap) placed on the toilet seat. Printed instructions were provided to each participant with detail on how to collect both the oropharyngeal and fecal specimens. These instructions were reviewed with the participant by a member of the study team at the start of the Day 1 telehealth visit.

Inclusion and Exclusion Criteria
Once obtained, samples were transported by FedEx service to .the Clinical Laboratory Improvement Amendments of 1988 (CLIA)-certified laboratory to avoid unnecessary hospital visits and to encourage compliance, given the self-quarantine status of enrolled patients.
Remote clinical follow-up via telehealth was performed at the following time points: Days 2, 3, 7, 10, 14, 21 and 30 including the following: • Obtaining AE data • Recording patient-reported COVID signs and symptoms • Documentation of patient's status as an outpatient, subsequently hospitalized, or died • Documentation of patient reported and vital signs (temperature and oxygen saturation) • Evaluate for increased severity of COVID-19-related disease • Collection of temperature and oximetry data

Timing of outcome assessments, including visit windows
Primary efficacy endpoint: respiratory viral clearance at Day 3.

Secondary efficacy endpoints
• Fecal viral clearance at Day 14.
• Progression to severe COVID, as a composite endpoint defined as O2 saturation <92% on room air in two consecutive measurements at least 2 hours apart OR requirement of hospitalization OR need for artificial ventilation OR death. • Resolution of symptoms

Adherence and protocol deviations
In this study, four pills are taken daily for 7 days. Compliance is assessed by the percentage of subjects who have taken the scheduled number of pills: % compliance = 100x (number of pills taken / 28 pills prescribed). Compliance is summarized by randomization group: mean % compliance as well as number and percentage of participants with more than 80% compliance (24 pills out of 28). Similarly, compliance with OP and fecal sampling was calculated.

Analysis populations
Participants who withdrew consent after randomization but before taking any sample or pill were excluded. The intention-to-treat (ITT) population includes all randomized patients according to the treatment they were randomized to receive (niclosamide or placebo). The per-protocol population is a subset of the participants in the full analysis (ITT) set who took at least 80% of study intervention. The safety population includes participants who took at least one pill.

Statistical Analyses
All participants (n=67) who attended the first telehealth visit were included in analyses. The cumulative probability of viral clearance in each group was estimated using the Kaplan-Meier estimator. Viral clearance was met the first day a participant's sample result was negative, provided that none of the subsequent sample results were positive. The starting time for survival analyses was the day of the first telehealth visit. If clearance was not met, the participant was censored at the time of the last available sample. For the primary analysis, the cumulative probabilities of clearance, based on oropharyngeal samples, was compared between treatment groups at Day 3 using a chi-square test based on the log of the -log transformation for the survival function[1]. Kaplan-Meier plots of cumulative probability of clearance were created and the log-rank test was used to compare the curves. Mean time to clearance up to day 14 for analyses involving respiratory samples and day 21 for analyses involving fecal samples were calculated using the area under the clearance-free survival curve.