Study to Evaluate the Effects of RO7496998 (AT-527) in Non-Hospitalized Adult and Adolescent Participants With Mild or Moderate COVID-19 (MORNINGSKY)
![]() |
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT04889040 |
Recruitment Status :
Terminated
(Based on program revaluation and in agreement with the co-development partner the sponsor took the decision to terminate this study.)
First Posted : May 17, 2021
Last Update Posted : February 4, 2022
|
- Study Details
- Tabular View
- No Results Posted
- Disclaimer
- How to Read a Study Record
Condition or disease | Intervention/treatment | Phase |
---|---|---|
COVID-19 | Drug: RO7496998 Drug: Placebo | Phase 3 |
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 1386 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Double (Participant, Investigator) |
Primary Purpose: | Treatment |
Official Title: | A Multicenter, Phase III Randomized, Double-Blind, Placebo-Controlled, Outpatient Study to Evaluate the Efficacy, Safety, Antiviral Activity of RO7496998 (AT-527) in Patients With Mild or Moderate COVID-19 |
Actual Study Start Date : | April 28, 2021 |
Actual Primary Completion Date : | November 17, 2021 |
Actual Study Completion Date : | November 17, 2021 |

Arm | Intervention/treatment |
---|---|
Experimental: RO7496998 (AT-527)
Orally administered, 550 mg twice daily (BID) for 5 days
|
Drug: RO7496998
275 mg tablets
Other Name: AT-527 |
Placebo Comparator: Placebo
The dose and regimen of the placebo will match that of AT-527.
|
Drug: Placebo
Matching tablets |
- Time to Alleviation or Improvement of COVID-19 Symptoms (21.5 hours) [ Time Frame: Up to 29 days ]
COVID-19 symptoms will be evaluated using the COVID-19 Symptom Diary (questions 1-12). The severity of each COVID-19 symptom will be recorded on a Likert scale (i.e none/mild/moderate/severe).
Alleviation of new symptoms is defined as the length of time taken from randomization to the point at which a Score of 0 or 1 has been maintained for a duration of at least 21.5 hours. For preexisting symptoms, the time from randomization to when a patient's symptoms have been maintained or improved (requires at least a single category improvement from baseline on the COVID-19 Symptom Diary Likert scale) for a duration of 21.5 hours.
- Time to Alleviation or Improvement of COVID-19 Symptoms (43 hours) [ Time Frame: Up to 29 days ]
COVID-19 symptoms will be evaluated using the COVID-19 Symptom Diary (questions 1-12). The severity of each COVID-19 symptom will be recorded on a Likert scale (i.e none/mild/moderate/severe).
Alleviation of new symptoms is defined as the length of time taken from randomization to the point at which a Score of 0 or 1 has been maintained for a duration of at least 43 hours. For preexisting symptoms, the time from randomization to when a patient's symptoms have been maintained or improved (requires at least a single category improvement from baseline on the COVID-19 Symptom Diary Likert scale) for a duration of 43 hours.
- Time to Alleviation of COVID-19 Symptoms (21.5 hours) [ Time Frame: Up to 29 days ]
Time from randomization to the point at which the following criterion is met and maintained for at least 21.5 hours.
- Score of 0 or 1 on Items 1-12 of the COVID-19 Symptom Diary.
- Time to Alleviation of COVID-19 Symptoms (43 hours) [ Time Frame: Up to 29 days ]
Time from randomization to the point at which the following criterion is met and maintained for at least 43 hours.
- Score of 0 or 1 on Items 1-12 of the COVID-19 Symptom Diary.
- Time to One-Category Improvement of Baseline Presenting COVID-19 Symptoms [ Time Frame: Up to 29 days ]Time from randomization to the point at which symptoms have improved by at least one category from baseline on the COVID-19 Symptom Diary Likert scale, maintained for at least 21.5 hours.
- Time to Alleviation of Individual Symptoms [ Time Frame: Up to 29 days ]
Time from randomization to the point at which the following criterion is met and maintained (for each individual symptom) for at least 21.5 hours.
- Score of 0 or 1 for Items 1-14 of the COVID-19 Symptom Diary
- Proportion of Participants Requiring Hospitalization for COVID-19 [ Time Frame: Up to 33 days ]
- Proportion of Participants with Greater than or Equal to 1 COVID-19 Related Medically Attended Visit [ Time Frame: Up to 33 days ]Medically attended visit is defined as hospitalization, emergency room (ER) visit, urgent care visit, physician's office visit, or telemedicine visit, with the primary reason for the visit being COVID-19.
- Duration of Fever [ Time Frame: Up to 29 days ]Time to return to an afebrile state (temperature ≤ 37.5°C) maintained for at least 21.5 hours
- Frequency of COVID-19 Related Complications [ Time Frame: Up to 33 days ]Examples of COVID-19 related complications include death, hospitalization, radiologically confirmed pneumonia, acute respiratory failure, sepsis, coagulopathy, pericarditis/myocarditis and cardiac failure.
- Proportion of Participants with any Post-Treatment Infection [ Time Frame: Up to 33 days ]
- Change from Baseline in the Amount of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) Virus RNA [ Time Frame: Up to 14 days ]SARS-CoV-2 virus RNA will be measured by reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR)
- Time to Cessation of SARS-CoV-2 Viral Shedding [ Time Frame: Up to 14 days ]Defined as the length of time from randomization to first time when the virus RNA by RT-qPCR is below the limit of detection.
- Proportion of Participants Positive for SARS-CoV-2 Virus RNA at Specified Timepoints [ Time Frame: Up to 14 days ]
- Area Under the Curve (AUC) in the Amount of SARS-CoV-2 Virus RNA [ Time Frame: Up to 14 days ]AUC in the amount of SARS-CoV-2 virus RNA from randomization to the last sample timepoint.
- Percentage of Participants with Adverse Events (AEs) [ Time Frame: Up to 33 days ]
- Plasma Concentration of AT-511, AT-551, AT-229 and AT-273 at Specified Timepoints [ Time Frame: Up to 7 days ]AT-511 is the free base form of RO7496998 (AT-527). Major metabolites are AT-551, AT-229, and AT-273 (a surrogate for the intracellular concentration of the active triphosphate metabolite AT-9010)

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 12 Years and older (Child, Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Positive SARS-CoV-2 diagnostic test (RT-PCR or validated rapid antigen test) ≤72 hours prior to randomization
- At least three of the following symptoms of at least moderate (score ≥2 as per COVID-19 Symptom Diary) intensity: nasal congestion or runny nose, sore throat, cough, shortness of breath, muscle or body aches, fatigue, headache, chills or sweats, feeling hot or feverish, nausea, vomiting, or diarrhea.
- Has symptoms consistent with mild or moderate COVID-19, as determined by the investigator, with onset ≤5 days before dosing on Day 1
Exclusion Criteria:
- Clinical signs indicative of COVID-19 illness requiring hospitalization
- Admitted to a hospital prior to randomization or is hospitalized (inpatient) at randomization due to COVID-19
- In the opinion of the investigator, is likely to experience imminent deterioration and require hospitalization
- Treatment with an investigational drug within 5 half-lives or 3 months (whichever is longer) of randomization
- Treatment with a COVID-19 therapeutic agent including, but not limited to, other direct or indirect acting antivirals against SARS-CoV-2 (such as remdesivir or favipiravir), systemic or inhaled steroids (such as dexamethasone or inhaled budesonide), colchicine, ivermectin, interferons, convalescent plasma, monoclonal antibodies against SARS CoV-2 or interleukin 6 (IL-6), intravenous immunoglobulin or other EUA-approved treatments within 3 months or less than 5 drug elimination half-lives (whichever is longer) prior to the screening visit
- Concomitant use of P-glycoprotein inhibitors or inducers listed as prohibited therapy in the protocol
- Known allergy or hypersensitivity to components of study drug
- Abnormal laboratory test results at screening
- Requirement of any prohibited medications during the study
- Other known active viral or bacterial infection at the time of screening, such as influenza
- Any clinically significant medical condition or laboratory abnormality that, in the opinion of the investigator, could jeopardize the safety of the patient or affect patient compliance or safety/efficacy observations during the study
- COVID-19 vaccination within ≤ 40-days prior to enrollment (second dose if applicable)

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04889040

Study Director: | Clinical Trials | Hoffmann-La Roche |
Responsible Party: | Hoffmann-La Roche |
ClinicalTrials.gov Identifier: | NCT04889040 |
Obsolete Identifiers: | NCT05126576 |
Other Study ID Numbers: |
CV43043 2020-005759-18 ( EudraCT Number ) |
First Posted: | May 17, 2021 Key Record Dates |
Last Update Posted: | February 4, 2022 |
Last Verified: | January 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Yes |
Plan Description: | Qualified researchers may request access to individual patient level data through the clinical study data request platform (www.vivli.org). Further details on Roche's criteria for eligible studies are available here (https://vivli.org/ourmember/roche/). For further details on Roche's Global Policy on the Sharing of Clinical Information and how to request access to related clinical study documents, see here (https://www.roche.com/research_and_development/who_we_are_how_we_work/clinical_trials/our_commitment_to_data_sharing.htm) |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
Coronavirus Disease 2019; COVID-19; antiviral drug; SARS-CoV-2; Mild to Moderate COVID-19; antiviral efficacy |
COVID-19 Respiratory Tract Infections Infections Pneumonia, Viral Pneumonia Virus Diseases |
Coronavirus Infections Coronaviridae Infections Nidovirales Infections RNA Virus Infections Lung Diseases Respiratory Tract Diseases |