Efficacy and Safety of SARS-CoV-2 Neutralizing Antibody JS016 in Hospitalized Chinese Patients with COVID-19: a Phase 2/3, Multicenter, Randomized, Open-Label, Controlled Trial

ABSTRACT Recombinant human severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) monoclonal antibody JS016 showed neutralizing and therapeutic effects in preclinical studies. The clinical efficacy and safety of the therapy needed to be evaluated. In this phase 2/3, multicenter, randomized, open-label, controlled trial, hospitalized patients with moderate or severe coronavirus disease 2019 (COVID-19) were randomly assigned in a 1:1 ratio to receive standard care or standard care plus a single intravenous infusion of JS016. The primary outcome was a six-level ordinal scale of clinical status on day 28 since randomization. Secondary outcomes include adverse events, 28-day mortality, ventilator-free days within 28 days, length of hospital stay, and negative conversion rate of SARS-CoV-2 nucleic acid on day 14. A total of 199 patients were randomized, and 197 (99 in the JS016 group and 98 in the control group) were analyzed. Most patients, 95 (96%) in the JS016 group and 97 (99%) in the control group were in the best category on day 28 since randomization. The odds ratio of being in a better clinical status was 0.31 (95% confidence interval [CI], 0.03 to 3.19; P = 0.33). Few adverse events occurred in both groups (3% in the JS016 group and 1% in the control group, respectively; P = 0.34). SARS-CoV-2 neutralizing antibody JS016 did not show clinical efficacy among hospitalized Chinese patients with moderate to severe COVID-19 disease. Further studies are needed to assess the efficacy of the neutralizing antibody to prevent disease deterioration and its benefits among groups of patients specified by disease course and severity. (This study has been registered at ClinicalTrials.gov under identifier NCT04931238.)


Protocol Summary 1.1 Rationale
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to a global pandemic including millions of critical cases and deaths. There is an urgent need for effective and safe therapies. JS016 is a recombinant neutralizing human SARS-CoV-2 monoclonal antibody binding to SARS-CoV-2 S protein, and thus provides potential therapeutic effects by blocking the attachment and entry of the virus into human cells. This study aims to evaluate the efficacy and safety of JS016 in patients hospitalized with COVID-19. The data from this study will inform decisions of the clinical use of JS016.

Design
This is a multicenter, randomized, open-label, controlled trial to evaluate the efficacy and safety of JS016 in patients hospitalized with COVID-19. Patients hospitalized to participating hospitals with moderate to severe COVID-19 will be randomized to receive standard care or standard care plus a single intravenous dose of JS016, and followed up for 28 days after randomization. The primary outcome, for clinical efficacy evaluation, is a six-level ordinal scale of clinical status on day 28 since randomization. Secondary outcomes include safety outcomes and other endpoints reflecting clinical efficacy. We plan to enroll a sample size of 200 participants. There will be a Data and Safety Monitoring Board.

Background and Study Rationale
Since the first reports of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the illness is still far from optimal control. The World Health Organization (WHO) declared COVID-19 outbreak a global pandemic on March 11, 2020. Glogally, as of Jan 2021, there have been more than 100 million confirmed cases, including more than 2.5 million deaths, reported to WHO. 5-32% of patients required ICU admission, and mortality rates varies between 1.4-33% 1-9 . However, except dexamethasone which has been shown to decrease mortality 10 , there is a lack of additional effective and safe therapies. The SARS-CoV-2 enters host cells through binding of the spike (S) protein to the cell surface receptor angiotensin-converting enzyme 2 (ACE2) 11 . As the crucial component of viral surface, the S protein can be further separated into S1 and S2 subdomains, with S1 binding to the host receptor and S2 mediating membrane fusion. The receptor-binding domain (RBD) at the S1 Cterminal domain engages cell surface ACE2 receptor. Once in the cell, the virus completes genome replication, protein translation, assembly, and shedding. Recombinant neutralizing human SARS-CoV-2 monoclonal antibody JS016, obtained from a B lymphocyte of a COVID-19 survivor, binds with high affinity to the RBD within the S1 subdomain of the SARS-CoV-2 S protein, thus blocks the binding between the virus and the cell surface receptor ACE2. The blocking of viral entry into cells is expected to relieve symptoms, mitigate the severity of disease, and improve clinical outcomes in patients infected with COVID-19. In vitro study and animal models showed potent neutralizing and therapeutic effects of JS016 on SARS-CoV-2 infection 12 . Two phase I trials among healthy volunteers has demonstrated a tolerable and safe drug profile of JS016.
Contact of patients with fever or respiratory tract symptoms from a community with COVID-19 case any time within the 14 days prior to symptom onset Cluster onset, i.e., two or more cases with fever and/or respiratory tract symptoms in settings like family, office, or class, within 14 days Clinical Criteria: Fever and/or COVID-19 related symptoms Typical chest imaging findings suggestive of COVID-19 Normal or decreased white blood cell and lymphocyte count Comfirmed case of SARS-CoV-2 infection is defined as a suspected case with a positive pathogenic or serologic test, including: A positive RT-PCR test of SARS-CoV-2 nucleic acid Viral genetic sequence highly homologous to the known sequence of SARS-CoV-2 A positive test of SARS-CoV-2 specific antibodies, including IgM and IgG Positive conversion of SARS-CoV-2 specific IgG, an increase of IgG titer by four times or more Disease Severity: Moderate illness is defined as fever or respiratory tract symptoms with pulmonary infiltration. Severe illness is diagnosed if a patient presents with any of the following conditions: 1. Dyspnea or respiratory rate ≥ 30 per minute 2. Arterial oxygen saturation ≤ 93% on room air at sea level 3. A ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) ≤ 300mmHg 4. Progressive worsening of symptoms, and pulmonary infiltration progressing by more than 50 percent within 24 to 48 hours. Critical illness is diagnosed if a patient develops respiratory failure requiring mechanical ventilation, shock, and/or multiple organ dysfunction requiring ICU admission.

Intervention
Participants are randomly assigned in a 1:1 ratio to receive standard care (control group) or standard care plus a single intravenous infusion of JS016, stratified by sites and disease severity at randomization (i.e., moderate or severe illness). A dose of 50mg/kg is based on tolerability, safety, and pharmacokinetic data. The standard care, based on the Eighth Edition of Clinical Practice of COVID-19 issued by China National Health Commission, includes monitoring, supplemental oxygen, respiratory support, and other supportive therapies 13 . Other medications are allowed except for those providing exogenous antibodies against SARS-CoV-2.

Objectives and outcomes
Objectives Outcomes Primary Efficacy of JS016 on clinical status Six-level ordinal scale of clinical status on 28 days since randomization 14-16 (eTable 1) Secondary Efficacy of JS016 on clinical outcomes Mortality rate within 28 days since randomization Ventilator free days within 28 days since randomization Length of hospital stay Efficacy of JS016 on viral clearance Negative conversion rate of SARS-CoV-2 nucleic acid on day 14 since randomization. Negative conversion rate of SARS-CoV-2 nucleic acid on day 7 and 21 will also be recorded. SARS-CoV-2 nucleic acid was defined as negative if both ORF and N gene turned negative. Safety assessment Adverse events (AEs) including allergic reaction, secondary infection, elevated alanine or aspartate transaminase (ALT or AST), acute kidney injury, acute myocardial infarction, septic shock, and gastrointestinal bleeding eTable 1. The primary outcome: six-level ordinal scale of clinical status Score Clinical status 1 Not hospitalized and without supplemental oxygen 2 Hospitalized without supplemental oxygen 3 Hospitalized with supplemental oxygen 4 Hospitalized with noninvasive ventilation or high flow nasal cannula 5 Hospitalized with invasive ventilation or ECMO 6 Death

Data Collection
Data are collected on randomization and day 7, 14, 21, and 28 since randomization. Case report form is attached in the Appendix. Weight conversion rates of SARS-CoV-2 nucleic acid will be analyzed by Cox proportional-hazards model. Continuous outcomes will be assessed with the use of generalized linear models or general linear models for repeated measures. All models will be adjusted for age, site, and clinical ordinal scale at randomization. P value less than 0.05 will be considered statistically significant. Statistical analyses will be performed by SPSS 22.0.

Data and Safety Monitoring Plan 6.1 Benefit/Risk Assessment
Since JS016 is a neutralizing antibody originated from human, off-target binding and tissue cross-reactivity is considered unlikely. Furthermore, the introduction of amino acid substitutions in the fragment crystallizable (Fc) region of JS016 lowered the risk of antibodydependent enhancement effect and Fc-mediated acute lung injury in animal models 12 . Potential risks of allergic reaction are also considered low based on good tolerability and safety profile of JS016 among healthy volunteers. Given the potent neutralizing activity of JS016 and the lack of effective therapy for COVID-19, the overall assessment of benefit and risk is favorable.

Protection against Study Risks
All participants will be acknowledged of the aim, process, and potential risks and benefits of the study. Informed consent will be obtained. Due to strict respiratory isolation regulations in participating hospitals, verbal consent will be allowed if approved by ethics committees. The confidentiality of all study participants will be protected. A participant may withdraw from the study at any time at the request of his/her own or representative, but data collected before the withdrawal can be used for analyses.

Management of Allergic Reactions
Infusions of the study drug will be administered at a controlled rate, and participants will be closely monitored during infusion. Infusing rate will be adjusted or stopped if indicated. Allergic reactions occur during or within six hours after infusion, and include symptoms and signs of, but do not limit to, fever, chills, nausea, headache, bronchospasm, hypotension, angioedema, throat irritation, rash, pruritus, myalgia, and dizziness. The severity of allergic reactions will be evaluated using the Division of Allergy and Infectious Diseases (DAIDS) Table  for Grading the Severity of Adult and Pediatric Adverse Events 18 and managed by investigators based on standard clinical practice. If the infusion is definitively discontinued, the participant will remain in the study for follow-up and further evaluations shown in the SoA.

Adverse Events (AEs) and Serious Adverse Events (SAEs)
An AE is any untoward or unfavorable medical occurrence in a participant, including any abnormal sign, symptom, or disease, temporally associated with their participation in study, whether or not considered related to the study. If a diagnosis is clinically evident (or subsequently determined), the diagnosis, rather than the individual signs and symptoms or lab abnormalities, will be recorded as the AE. Adverse events are serious if they lead to one of the following outcomes: • Death • Life-threatening (i.e., an immediate threat to life) • Hospitalization or prolongation of hospitalization • Persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions • Congenital abnormalities/birth defects • Other important medical events that may jeopardize the participant and/or may require intervention to prevent one of the outcomes listed above Severity of AEs will be evaluated according to the DAIDS Table for Grading the Severity of Adult and Pediatric Adverse Events 18 . AEs will be reported by participants, caregivers, or investigators, the last of whom are responsible for documenting, recording, and following up AEs. All AEs and SAEs will be collected from randomization to day 28, and followed up until resolution, stabilization, or loss of followup. The DSMB may request to stop enrollment for safety reasons, inform ethics committees, and determine whether it is safe to resume the study.

Data and Safety Monitoring
Study supervisors will be responsible for ensuring participants' safety and for reporting AEs to the Ethics Committees and Data and Safety Monitor Board (DSMB). There will be an independent DSMB who are responsible to evaluate the progress of the study and the quality of data collection, management, and analyses. Another goal of the DSMB is to review interim data and use pre-specified rules to determine the continuing safety and efficacy of the investigational drug. Only masked data will be presented to the DSMB. All data are confidential. Participant identities will be kept confidential unless safety concerns necessitate unmasking some or all data.