ACTIV-6: COVID-19 Study of Repurposed Medications - Arm F (Montelukast)

The purpose of this study is to evaluate the effectiveness of repurposed medications (study drug(s) in reducing symptoms of non-hospitalized participants with mild to moderate COVID-19. Participants will receive either study drug or placebo. They will self-report any new or worsening symptoms or medical events they may experience while taking study drug or placebo. This study is intended to be all remote with no in person visits, unless the study team feels it is in the best interest of a participant to see them in person.

Prior and current drug arms are listed on clinicaltrials.gov and will be updated with the activation of any new drug arms. Each study arm will also have its own clinicaltrials.gov entry and will include "Pro00107921" in the Unique Protocol ID.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel betacoronavirus that first emerged in December 2019 and has since caused a global pandemic unseen in almost a century with respect to the number of cases and overall mortality. The clinical disease related to SARS-CoV-2 is referred to as Coronavirus Disease 2019 (COVID-19). Over 2020, advances were made for treatment of COVID-19 and several vaccinations have received emergency use authorization for prevention of SARS-CoV-2 infections. However, the pandemic continues to evolve with new variants and surges of infections in different regions of the world, requiring an ongoing evidence-generating platform, in particular for the treatment of COVID-19 infection in the outpatient setting.

This proposed platform protocol can serve as an evidence generating system for prioritized drugs repurposed from other indications with an established safety record and preliminary evidence of clinical efficacy for the treatment of COVID-19. The ultimate goal is to evaluate if repurposed medications can make participants feel better faster and reduce death and hospitalization.

This platform protocol is designed to be flexible so that it is suitable for a wide range of settings within healthcare systems and in community settings where it can be integrated into routine COVID-19 testing programs and subsequent treatment plans. This platform protocol will enroll participants in an outpatient setting with a confirmed polymerase chain reaction (PCR) or antigen test for SARS-CoV-2.

Participants will be randomized to study drugs or placebo based on the arms that are actively enrolling at the time of randomization. Study drugs may be added or removed according to adaptive design and/or emerging evidence. When there are multiple study drugs available, randomization will occur based on appropriateness of each drug for the participant as determined by the study protocol and investigator and participant equipoise. Each participant will be required to randomize to at least one study drug versus placebo. The probability of placebo to treatment will remain the same regardless of eligibility decisions.

Eligible participants will be randomized (1:1), in a blinded fashion, to either the study drug arm or placebo arm in addition to standard of care. As additional study drugs are added, the randomization will be altered to leverage placebo data across arms. Participants will receive a complete supply study drug or placebo with the quantity depending on the study drug/placebo to which they are randomized.

All study visits are designed to be remote. However, screening and enrollment may occur in-person at sites and unplanned study visits may occur in-person or remotely, as deemed appropriate by the site investigator for safety purposes. Participants will be asked to complete questionnaires and report safety events during the study. Participants will be prompted by the online system to report safety events and these will be reviewed and confirmed via medical records and site staff, as necessary.

Eligibility Criteria:
Inclusion Criteria:

* Completed Informed Consent
* Age ≥ 30 years old
* Confirmed SARS-CoV-2 infection (or reinfection) by any authorized or approved polymerase chain reaction (PCR) or antigen test collected within 10 days of screening
* Two or more current symptoms of acute infection for ≤7 days. Symptoms include the following: fatigue, dyspnea, fever, cough, nausea, vomiting, diarrhea, body aches, chills, headache, sore throat, nasal symptoms, new loss of sense of taste or smell

Exclusion Criteria:

* Prior diagnosis of COVID-19 infection (\> 10 days from screening)
* Current or recent (within 10 days of screening) hospitalization
* Known allergy/sensitivity or any hypersensitivity to components of the study drug or placebo
* Known contraindication(s) to study drug including prohibited concomitant medications