CDI-988 Safety Study in Healthy Participants

August 17, 2026 updated by: Cocrystal Pharma, Inc.

A Phase 1, Randomized, Double-Blinded, Placebo-Controlled, First-in-Human Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of Single-Ascending and Multiple-Ascending Doses of Oral CDI-988 in Healthy Adult Participants

The goal of this clinical trial is to learn about the safety and pharmacokinetics (PK, the amount of drug in the blood) of a new drug called CDI-988 in healthy volunteers.

The main questions it aims to answer are:

  • Are there any side effects of the drug?
  • What is the amount of drug that reaches the bloodstream? Participants will be assigned by chance to take either CDI-988 or placebo by mouth and have physical exams, electrocardiograms (ECGs), vital signs, and blood tests to look for any side effects.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

CDI-988 is a severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) 3-chymotrypsin-like (3CL) protease inhibitor for oral administration. This study is being conducted in 2 parts to examine the safety, tolerability, and PK of CDI-988 in healthy participants. Part 1 will entail escalating single doses in sequential cohorts and Part 2 will enroll escalating multiple-dose cohorts. Participants will be monitored for adverse events, vital signs, laboratory values, and electrocardiograms (ECGs).

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
94

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Australia
    • New South Wales
      • Randwick, New South Wales, Australia, 2031
        • Scientia Clinical Research Pty Ltd

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy males or non-pregnant, non-lactating females
  • Body weight of at least 45 kg.
  • Body mass index ≥18.0 and ≤32.0 kg/m2
  • Good state of mental and physical health
  • Negative severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test

Exclusion Criteria:

  • Received an investigational drug within 30 days
  • Received a coronavirus disease 2019 (COVID-19) vaccine within 7 days
  • Drug or alcohol abuse in the past 12 months
  • Clinically significant abnormal biochemistry, hematology, coagulation, urinalysis test results
  • Clinically significant abnormal ECG or vital signs

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: SAD Cohort 1A
first single-dose level
Drug: Placebo
matching placebo
Drug: CDI-988
SARS-CoV-2 3CL protease inhibitor
Experimental: SAD Cohort 1B
second single-dose level
Drug: Placebo
matching placebo
Drug: CDI-988
SARS-CoV-2 3CL protease inhibitor
Experimental: SAD Cohort 1C
third single-dose level; food-effect cohort
Drug: Placebo
matching placebo
Drug: CDI-988
SARS-CoV-2 3CL protease inhibitor
Experimental: SAD Cohort 1D
fourth single-dose level
Drug: Placebo
matching placebo
Drug: CDI-988
SARS-CoV-2 3CL protease inhibitor
Experimental: MAD Cohort 2A
first multiple-dose level
Drug: Placebo
matching placebo
Drug: CDI-988
SARS-CoV-2 3CL protease inhibitor
Experimental: MAD Cohort 2B
second multiple-dose level
Drug: Placebo
matching placebo
Drug: CDI-988
SARS-CoV-2 3CL protease inhibitor
Experimental: MAD Cohort 2C
third multiple-dose level
Drug: Placebo
matching placebo
Drug: CDI-988
SARS-CoV-2 3CL protease inhibitor
Experimental: SAD Cohort 1E
fifth dose level; food effect cohort
Drug: Placebo
matching placebo
Drug: CDI-988
SARS-CoV-2 3CL protease inhibitor
Experimental: SAD Cohort 1F
sixth dose level
Drug: Placebo
matching placebo
Drug: CDI-988
SARS-CoV-2 3CL protease inhibitor
Experimental: MAD Cohort 2D
4th multiple dose level
Drug: Placebo
matching placebo
Drug: CDI-988
SARS-CoV-2 3CL protease inhibitor
Experimental: MAD Cohort 2E
5th multiple dose level
Drug: Placebo
matching placebo
Drug: CDI-988
SARS-CoV-2 3CL protease inhibitor
Experimental: MAD Cohort 2F
6th multiple dose level
Drug: Placebo
matching placebo
Drug: CDI-988
SARS-CoV-2 3CL protease inhibitor

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
ECGs
Time Frame: Day 1 to 7 days after last dose
number of participants with clinically significant changes from baseline in ECGs
Day 1 to 7 days after last dose
Adverse Events
Time Frame: Up to 17 days
number of participants with treatment-emergent adverse events
Up to 17 days
Laboratory Abnormalities
Time Frame: Up to 17 days
number of participants with clinically significant laboratory abnormalities
Up to 17 days
Vital Signs
Time Frame: Day 1 to 7 days after last dose
number of participants with clinically significant changes from baseline in vital signs
Day 1 to 7 days after last dose

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Part 1 SAD Maximum Plasma Concentration (Cmax)
Time Frame: predose, 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12, 24, 36, and 48 h post dose
Cmax was evaluated from the PK samples collected
predose, 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12, 24, 36, and 48 h post dose
Part 1 SAD Time of Maximum Plasma Concentration (Tmax)
Time Frame: predose, 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12, 24, 36, and 48 h post dose
Tmax was evaluated from the PK samples collected.
predose, 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12, 24, 36, and 48 h post dose
Part 1 SAD Area Under the Plasma Concentration-time Curve (AUC) From Time 0 to t (AUC0-t) of CDI-988
Time Frame: pre dose, 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12, 24, 36, and 48 h post dose
AUC0-t was evaluated from the PK samples collected
pre dose, 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12, 24, 36, and 48 h post dose
Part 1 SAD Elimination Rate Constant (Lambda Z)
Time Frame: predose, 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12, 24, 36, and 48 h post dose
λz was evaluated from the PK samples collected
predose, 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12, 24, 36, and 48 h post dose
Part 1 SAD Terminal Elimination Half-life (t1/2)
Time Frame: predose, 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12, 24, 36, and 48 h post dose
t1/2 was evaluated from the PK samples collected.
predose, 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12, 24, 36, and 48 h post dose
Part 2 MAD: Maximum Plasma Concentration (Cmax) of CDI-988
Time Frame: Day 1, Day 5 and Day 10: Pre-dose, 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12, 24, 36 and 48h post-dose
Cmax was evaluated from the PK samples collected.
Day 1, Day 5 and Day 10: Pre-dose, 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12, 24, 36 and 48h post-dose
Part 2 MAD: Time of Maximum Plasma Concentration (Tmax) of CDI-988
Time Frame: Day 1, 5 or 10: pre-dose and at 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4. 6, 8, 12, 24, 36, and 48 h
Tmax was evaluated from the PK samples collected.
Day 1, 5 or 10: pre-dose and at 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4. 6, 8, 12, 24, 36, and 48 h
Part 2 MAD: Area Under the Plasma Concentration-time Curve From Time 0 to t (AUC0-t) of CDI-988
Time Frame: Day 1, 5 or 10: pre-dose and at 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4. 6, 8, 12, 24, 36, and 48 h
AUC0-t was calculated from the PK samples collected
Day 1, 5 or 10: pre-dose and at 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4. 6, 8, 12, 24, 36, and 48 h
Part 2 MAD: Elimination Rate Constant (λz) of CDI-988
Time Frame: Day 1, 5 or 10: pre-dose and at 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4. 6, 8, 12, 24, 36 and 48 h
λz was evaluated from the PK samples collected
Day 1, 5 or 10: pre-dose and at 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4. 6, 8, 12, 24, 36 and 48 h
Part 2 MAD: Terminal Elimination Half-life (t1/2) of CDI-988
Time Frame: Day 1, 5 or 10: pre-dose and at 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4. 6, 8, 12, 24, 36 and 48 h
T1/2 was evaluated from the PK samples collected
Day 1, 5 or 10: pre-dose and at 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4. 6, 8, 12, 24, 36 and 48 h

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Cocrystal Pharma, Inc.

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Cocrystal Pharma Australia Pty Ltd.
Beyond Drug Development Pty Ltd.
Resolutum Global Pty Ltd.
Scientia Clinical Research Pty Ltd

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Christopher Argent, MD, Scientia Clinical Research

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 27, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 23, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 23, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 28, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 28, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 4, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 19, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 17, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CDI-988-P1-001

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

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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