Study terminated due to the rapidly evolving environment for the treatment of Covid-19 and ongoing challenges to identify and enroll qualified patients to participate.

The therapeutic hypothesis for the use of losmapimod in COVID-19 disease is that increased mortality and severe disease is caused by p38 mitogen-activated protein kinase (MAPK)-mediated exaggerated acute inflammatory response resulting from SARS-CoV-2 infection.

The study Sponsor hypothesizes that the early initiation of p38α/β inhibitor therapy in patients hospitalized with moderate COVID-19 who are at increased risk of a poor prognosis based on older age and elevated systemic inflammation will reduce clinical deterioration including progression to respiratory failure and death.

To address this hypothesis, Fulcrum Therapeutics is conducting a Phase 3, multicenter, randomized, double-blind, placebo-controlled study that will evaluate the safety and efficacy of losmapimod versus placebo in subjects 40 and older who are hospitalized with moderate COVID-19 disease.

The therapeutic hypothesis for the use of losmapimod in COVID-19 disease is that increased disease severity and consequent increased mortality is caused by p38 mitogen-activated protein kinase (MAPK)-mediated exaggerated acute inflammatory response resulting from SARS-CoV-2 infection.

It is anticipated that the early initiation of p38α/β inhibitor therapy in patients with moderate COVID-19 will prevent further clinical deterioration and reduce the need for both increased respiratory support as well as mortality. This is the main hypothesis for this study.

To address this hypothesis, Fulcrum Therapeutics is conducting a Phase 3, multicenter, randomized, double-blind, placebo-controlled study that will evaluate the safety and efficacy of losmapimod versus placebo in subjects with COVID-19 disease.

Losmapimod is currently in Phase 2 clinical trials for the treatment of facioscapulohumeral dystrophy (FSHD) and has previously been administered to more than 3600 adult healthy volunteers and subjects including participants in a large Phase 3 trial which evaluated clinical outcomes and safety after major cardiovascular events.

Patients will participate in this study for approximately 34 days. The total treatment duration will be 14 days. Subjects will be evaluated during a 3 day pre-treatment period (Screening and Baseline Visits) to establish pre-treatment baseline assessments and eligibility. Subjects will then be randomized to treatment with losmapimod or placebo for 14 days and assessed frequently for changes from pre-treatment in various clinical outcome assessments. Patients must have a confirmed diagnosis of COVID-19 by viral PCR prior to randomization and first dosing. Patients will receive 15 mg of losmapimod, or placebo twice daily given as two 7.5 mg tablets per dose by mouth: for a total of 4 pills or 30 mg daily for 14 consecutive days. All study visits during the first week of treatment are anticipated to be conducted in the inpatient setting while later visits are anticipated to be conducted as outpatient.

The primary endpoint of the study is to assess the efficacy of losmapimod tablets compared with placebo for the treatment of COVID-19 when administered concurrently with the local standard of care. Secondary endpoints include evaluating the effect of losmapimod compared with placebo on clinical outcomes, clinical status, effect on survival, safety, and tolerability and to characterize changes in the levels of SARS-CoV-2 infection.

Inclusion Criteria:

• Able and willing to provide written informed consent
• Willing and able to comply with all study procedures.
• Confirmed infection with SARS-CoV-2 virus at or before the baseline visit by polymerase chain reaction (PCR) testing
• ≤7 days to the time of randomization from the time of collection of the specimen that tested positive for the SARS-CoV-2 virus
• Hospitalization at the time of the baseline visit
• ≥90% oxygen saturation on room air and/or ≥94% oxygen saturation on oxygen administration at 2 L/min by nasal cannula at the baseline visit
• Radiographic (X-ray or computed tomography scan, per local standard of care) and/or clinical evidence of pulmonary involvement consistent with COVID-19 at screening or baseline, per the judgment of the investigator
• Clinical syndrome consistent with COVID-19 at screening, per the judgment of the investigator (CDC 2020)
• CRP at screening >15 mg/L (i.e., >1.5 mg/dL) on local laboratory testing
• Agrees to practice an approved method of birth control

Exclusion Criteria:

• Inability to take oral medication at screening or baseline visit
• Evidence at screening or baseline of critical COVID-19 disease (e.g., cardiac failure, septic shock) or severe pulmonary involvement)
• Positive pregnancy test at screening for women of childbearing potential
• Lactating female at baseline for women of childbearing potential Note: A female will be considered eligible who is lactating at screening if she agrees to discontinue breastfeeding for the duration of the trial plus 14 days post last dose
• ≥5 × upper limit of normal (ULN) for alanine or aspartate aminotransferases or total bilirubin >1.5 × ULN at screening or known history of Child-Pugh Class C, hepatitis B or C, or HIV infection
• Glomerular filtration rate <30 mL/min/1.73 m2 at screening
• QTcF >450 msec for male or >470 msec for females or evidence of cardiac dysrhythmia at screening
• Significant history or evidence of clinically significant disorder, condition, current illness, illicit drug or other addiction, or disease that, in the opinion of the Investigator, would pose a risk to subject safety or interfere with the study evaluation, procedures, or completion
• Has been treated with immunomodulators or immunosuppressants including, but not limited to, interleukin (IL)-6 inhibitors, tumor necrosis factor (TNF) inhibitors, anti-IL-1 agents, and Janus kinase inhibitors, within 5 half-lives or 30 days, whichever is longer, prior to randomization, or plan to receive these agents any time during the study period
• Treatment with hydroxychloroquine/ chloroquine in the past 30 days or plan to receive these agents as part of investigational clinical trials or SOC any time during the study period
• Recent (within 30 days) or current participation in other COVID-19 therapeutic trials or expanded access programs
• Prior or current participation in COVID-19 vaccine trials

Full Analysis Set: included all participants who were randomized and received any study drug.

Up to Day 28

Safety population which included all participants who received any study drug.

This study will be performed in a double-blind fashion. The investigator, study staff, subjects, Sponsor, and monitor will remain blinded to the treatment until study closure.