A Study Evaluating MDX2301 in Healthy Adults and Adults at Higher Risk for Severe COVID-19.

A Phase 1a/b Randomized, Double-Blind, Placebo-Controlled Dose Escalation Study Evaluating MDX2301 in Healthy Adults and Adults at Higher Risk for Severe COVID-19

This first-in-human study is designed to evaluate the safety, tolerability, pharmacokinetics, anti-drug antibodies, and neutralizing activity of MDX2301 administered by intravenous (IV), intramuscular (IM), or subcutaneous (SC) routes in healthy adults and adults at higher risk for severe COVID-19. Participants will receive single IV, IM, and SC doses of MDX2301 or placebo and a repeat IM or SC dose approximately 3 months apart of MDX2301 or placebo.

Study Overview

• Status: Recruiting
• Conditions: COVID -19; COVID-19 (Prevention)
• Intervention / Treatment: Biological: MDX2301; Biological: MDX2301; Biological: Normal Saline; Biological: Normal Saline

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: ModeX Therapeutics, An OPKO Health Company; Phone Number: 857-233-9936; Email: info@modextx.com

Study Locations

• United States
  • Nevada
    • Las Vegas, Nevada, United States, 89113
      • Recruiting
      • TrialMed Clinical Research Unit
      • Principal Investigator: Shawn Searle, MD
      • Contact: ModeX Therapeutics; Phone Number: +1 857-233-9936; Email: info@modextx.com
  • Texas
    • Austin, Texas, United States, 78744
      • Recruiting
      • TrialMed Clinical Research Unit
      • Principal Investigator: Kristie Miller, MD
      • Contact: ModeX Therapeutics; Phone Number: +1 857-233-9936; Email: info@modextx.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria

Healthy Adults

1. Participant is a healthy male or female, 18 to 64 years of age.

2. Participant is in good health in the opinion of the investigator.

   Adults at Higher Risk for Developing Severe COVID-19:

3. Participant is a male or female, 18 to 64 years of age.

4. Participant is at higher risk for developing severe COVID-19, with 1 or more of the following risk factors:

   1. Asthma
   2. Diabetes
   3. Cerebrovascular disease, which affects blood flow to the brain.
   4. Chronic kidney disease
   5. Chronic lung disease
   6. Cardiac disease
   7. Chronic liver disease
   8. Cystic fibrosis
   9. HIV clinically stable on antiretroviral therapy for at least 6 months prior to screening.
   10. Sickle cell disease or thalassemia
5. Participant is clinically stable with no clinically significant abnormalities.

6. Participant has not been hospitalized within the 12 months prior to screening or is not expected to be hospitalized during the study due to underlying medical conditions.

   All Participants

7. Female participants of childbearing potential must have a negative urine pregnancy test.
8. Female participants of childbearing potential must agree to follow instructions for a highly effective birth control method.
9. Participant is able to understand and sign the informed consent form prior to undergoing any study procedures.
10. Participant is willing and able to comply with scheduled visits and procedures.

Exclusion Criteria:

Healthy Adults

1. Participant has any chronic or significant medical condition that, in the opinion of the investigator, might compromise the participant's safety or interfere with evaluation of the study drug.

2. Participant has evidence of active HIV, hepatitis B, or hepatitis C infections at screening.

   Adults at Higher Risk for Severe COVID-19:

3. Participant has any serious disease, condition, or disorder that, in the opinion of the investigator, might compromise the participant's safety or interfere with evaluation of the study drug or interpretation of study results, or may lead to hospitalization or death within the study period.

4. Participant has evidence of active hepatitis B or hepatitis C infections at screening.

   All Participants

5. Participant has abnormal vital signs, ECG findings, or laboratory values at Screening or Day -1.
6. Participant tests positive for SARS-CoV-2 infection at screening.
7. Participant self-reports having COVID-19 or received COVID-19 antiviral for prophylaxis or treatment prior to Day 1.
8. Participant has received a SARS-CoV-2 vaccine prior to dosing.
9. Participant has received a monoclonal antibody (mAb) for SARS-CoV-2 or convalescent plasma for SARS-CoV-2 prior to Day 1.
10. Participant has received or is expected to receive for the duration of the study immunoglobulin, blood-derived products, high-dose systemic corticosteroids, or other immunosuppressant drugs within 6 months prior to Day 1.
11. Participant is pregnant, breastfeeding, or seeking pregnancy while on the study.
12. Participant with a known clinically significant bleeding disorder that would prohibit the participant from receiving an IV infusion or IM or SC injection.
13. Participant had major surgery within 30 days prior to Day 1.
14. Participant has donated blood prior to screening.
15. Participant has any skin condition and/or tattoo that may interfere with the evaluation of safety at the injection site.
16. Participant has a history of alcoholism or illicit drug use prior to screening or a positive test for drugs of abuse at screening or on Day -1.
17. Participant is a current smoker or user of other nicotine containing products on a daily basis.
18. Participant has received an investigational product within 30 days prior to Day 1.

19. Participant has a known hypersensitivity to any components of MDX2301, any of its excipients or closely related compounds.

    For All Participants, Temporary Exclusions for Randomization on Day 1 if Remains within the Screening Window:

20. Participant has any acute illness, within 3 days of Day 1.
21. Participant has vital signs considered by the investigator to be clinically significant prior to study drug administration.
22. Participant has had close contact with anyone confirmed to have SARS-CoV-2 infection within the 7 days prior to Day 1.
23. Any acute drug therapy prescribed by a physician within 7 days prior to Day 1.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Sequential Assignment
• Masking: Quadruple

Number of Arms

6

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Single Dose Healthy Adults MDX2301; Healthy Adults will receive a single dose of MDX2301 as intravenous infusion, intramuscular injection, or subcutaneous injection.	Biological: MDX2301; MDX2301 as intravenous infusion, intramuscular injection, or subcutaneous injection.; Biological: MDX2301; MDX2301 as intramuscular injection or subcutaneous injection.
Placebo Comparator: Single Dose Healthy Adults Placebo; Healthy Adults will receive a single dose of placebo as intravenous infusion, intramuscular injection, or subcutaneous injection.	Biological: Normal Saline; Placebo as intravenous infusion, intramuscular injection, or subcutaneous injection.; Biological: Normal Saline; Placebo as intramuscular injection or subcutaneous injection.
Experimental: Repeat Dose Healthy Adults MDX2301; Healthy Adults will receive a single dose of MDX2301 as intramuscular injection or subcutaneous injection and then receive a repeat dose of MDX2301, 3 months later as intramuscular injection or subcutaneous injection.	Biological: MDX2301; MDX2301 as intravenous infusion, intramuscular injection, or subcutaneous injection.; Biological: MDX2301; MDX2301 as intramuscular injection or subcutaneous injection.
Placebo Comparator: Repeat Dose Healthy Adults Placebo; Healthy Adults will receive a single dose of placebo as intramuscular injection or subcutaneous injection and then receive a repeat dose of placebo 3 months later as intramuscular injection or subcutaneous injection.	Biological: Normal Saline; Placebo as intravenous infusion, intramuscular injection, or subcutaneous injection.; Biological: Normal Saline; Placebo as intramuscular injection or subcutaneous injection.
Experimental: Single-Dose Higher Risk Adults MDX2301; Adults at higher risk for severe COVID-19 will receive a single dose of MDX2301 as intramuscular injection or subcutaneous injection.	Biological: MDX2301; MDX2301 as intravenous infusion, intramuscular injection, or subcutaneous injection.; Biological: MDX2301; MDX2301 as intramuscular injection or subcutaneous injection.
Placebo Comparator: Single-Dose Higher Risk Adults Placebo; Adults at higher risk for severe COVID-19 will receive a single dose of placebo as intramuscular injection or subcutaneous injection.	Biological: Normal Saline; Placebo as intravenous infusion, intramuscular injection, or subcutaneous injection.; Biological: Normal Saline; Placebo as intramuscular injection or subcutaneous injection.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adverse Events	Incidence and severity of adverse events (AEs) and serious AEs (SAEs), including changes in clinical laboratory parameters.	Baseline until end of study, up to approximately 12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measure of maximum serum concentration (Cmax) of MDX2301	Characterize pharmacokinetic (PK) parameter Cmax after administration of MDX2301	12 months
Measure of time to maximum concentration (Tmax) of MDX2301	Characterize pharmacokinetic (PK) parameter Tmax after administration of MDX2301	12 months
Measure of terminal half-life (t1/2) of MDX2301	Characterize pharmacokinetic (PK) parameter t1/2 after administration of MDX2301.	12 months
Measure of area under the serum concentration-time curve (AUC) extrapolated to infinity of MDX2301	Characterize pharmacokinetic (PK) parameters AUC after administration of MDX2301	12 months
Measure of volume of distribution (Vd) of MDX2301	Characterize pharmacokinetic (PK) parameter Vd after administration of MDX2301.	12 months
Incidence of treatment-emergent anti-drug antibodies (ADA) of MDX-2301	Quantification of ADAs after MDX2301 administration	12 months
Evaluation of serum virus neutralizing antibodies of MDX2301	Measure of the level of serum virus neutralizing antibodies of MDX2301 against relevant SARS-CoV-2 variants.	12 months

Collaborators and Investigators

• Sponsor: ModeX Therapeutics, An OPKO Health Company
• Investigators: Principal Investigator: Trial Med, TrialMed

Study record dates

Study Major Dates

• Study Start (Actual): March 24, 2026
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: February 10, 2026
• First Submitted That Met QC Criteria: February 25, 2026
• First Posted (Actual): March 3, 2026

Study Record Updates

• Last Update Posted (Actual): May 18, 2026
• Last Update Submitted That Met QC Criteria: May 15, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Lung Diseases; Pneumonia, Viral; Pneumonia; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; COVID-19; Pharmaceutical Preparations; Crystalloid Solutions; Isotonic Solutions; Solutions; Saline Solution
• Other Study ID Numbers: MDX-2301-101

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No