A Study to Evaluate the Safety and Efficacy of CD388 for Prevention of Influenza

Not Applicable

Not yet recruiting

• Conditions: Influenza

• Registration Number: NCT07159763
• Lead Sponsor: Cidara Therapeutics Inc.

Brief Summary

The purpose of this study is to evaluate how well CD388 works in preventing symptomatic laboratory-confirmed influenza infections, as compared to placebo, when given as a single dose via 3 subcutaneous (SQ) injections to adult and adolescent participants who are at higher risk of developing influenza complications, and to evaluate the safety and tolerability of CD388, as compared to placebo.

Detailed Description

This is a Phase 3, randomized, double-blind, placebo-controlled, parallel-group, multicenter study to evaluate the efficacy, safety, and tolerability of CD388 administered as a single dose via 3 SQ injections in adult and adolescent participants who are at higher risk of developing complications from influenza.

Study Timeline

• Status Verified: 2025-08
• Study First Submitted: 2025-08-29
• Study First Submitted QC: 2025-08-29
• Last Update Submitted: 2025-08-29
• Study Start: 2025-09-01
• Study First Posted: 2025-09-08
• Last Update Posted: 2025-09-08
• Primary Completion: 2027-01
• Study Completion: 2027-01-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 5500

Inclusion Criteria

1. Must be 12 years of age or older at the time of signing the informed consent.

2. Written informed consent and any locally required authorization (e.g., Health Insurance Portability and Accountability Act [HIPAA] in the US) obtained from the participant before performing any protocol-related procedures, including screening evaluations. For participants under the legal age of consent as defined by local regulations, the parent(s) or legal guardian(s) may be required to give their signed written informed consent and participants may sign an assent form as specified by local law.

3. Has negative rapid antigen tests for influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) prior to dosing at Day 1.

4. Weight is ≥ 40 kilograms (kg) at screening.

5. Body Mass Index (BMI; calculated as weight in kg divided by height in meters [m] squared)) is ≥ 18 kg/m^2 at screening.

6. In the opinion of the Investigator, must be able to comply with the requirements of the protocol and be able to read, understand, and complete questionnaires in the electronic diary (eDiary), work with smartphones/tablets/computers (if applicable, with assistance by a caregiver, surrogate, or legally authorized representative), and be willing and able to adhere to the prohibitions and restrictions specified in this protocol. If an appropriate language version is not available for the eDiary assessments, the participant should not be enrolled.

7. Must be assessed by the Investigator as medically stable and not requiring significant change in maintenance therapy and has not been hospitalized for worsening disease or any significant medical event during the 2 months before screening

8. Must agree to the following contraception requirements:

   1. Females of childbearing potential must use a highly effective, preferably user-independent, method of contraception (failure rate of less than 1 percent per year when used consistently and correctly) from ≥2 weeks prior to randomization and agree to remain on a highly effective method from Day 1 until 32 weeks after study intervention administration, the end of relevant systemic exposure. Note: A woman is considered of childbearing potential (i.e., fertile) following menarche and until becoming postmenopausal, unless permanently sterile. Permanent sterilization methods include hysterectomy, bilateral salpingectomy, and bilateral oophorectomy. A postmenopausal state is defined as no menses for 12 months without an alternative medical cause. A high follicle stimulating hormone (FSH) level in the postmenopausal range may be used to confirm a postmenopausal state in women not using hormonal contraception or hormonal replacement therapy. However, in the absence of 12 months of amenorrhea, a single FSH measurement is insufficient.

   2. Female participants must agree not to donate or freeze eggs (ova, oocytes) for future use for the purposes of assisted reproduction from Day 1 until 32 weeks after study intervention administration.

   3. Male participants must agree to wear a condom when engaging in any activity that allows for passage of ejaculate to another person from Day 1 until 32 weeks after study intervention administration. Male participants who are partners of females of childbearing potential should also be advised of the benefit for female partners who are of childbearing potential to additionally use a highly effective method of contraception.

      Note: Contraceptive (birth control) use by participants should be consistent with local regulations regarding the acceptable methods of contraception for those participating in clinical studies.

   4. Male participants must agree not to donate sperm from Day 1 until 32 weeks after study drug administration.

9. Must agree not to donate blood or blood products from Day 1 until 32 weeks after study intervention administration.

10. Must be willing to provide verifiable identification, has means to be contacted, and is able to contact the Investigator/study site and communicate reliably during participation in the study.

11. In addition to inclusion criteria 1 through 10 above, participants are eligible to be included in Primary Stratum A of the study (higher risk non-immunocompromised) only if one or more of the following criteria apply:

    1. Has a chronic pulmonary disease (e.g., chronic obstructive pulmonary disease [COPD], chronic bronchitis, cystic fibrosis, idiopathic pulmonary fibrosis).
    2. Has chronic persistent asthma requiring daily therapy.
    3. Has a history of cardiac disease (e.g., congestive heart failure, congenital heart disease, coronary artery disease).
    4. Has a neurologic disorder (not including Alzheimer's disease or dementia) or had a previous stroke.
    5. Has insulin-dependent diabetes.
    6. Has chronic kidney disease (CKD) (estimated creatinine clearance 30 to 59 milliliter per minute [mL/min] using Cockcroft-Gault equation) (not including hemodialysis). NOTE: Documented creatinine clearance value obtained within the last 12 months prior to screening is acceptable.
    7. Has a chronic liver disorder (but not worse than Child-Pugh Class A) as determined within the last 12 months prior to screening.

12. In addition to inclusion criteria 1 through 10 above, participants are eligible to be included in Primary Stratum B of the study (immunocompromised) only if one or more of the following criteria apply:

    1. Has a solid tumor cancer and is receiving immunosuppressive treatment.

    2. Has a hematologic malignancy.

    3. Participants who have had a transplant must satisfy at least one of the following:

       • Had a solid organ transplant more than 6 months and less than 2 years prior to screening, and/or
       • Had a hematopoietic cell transplant more than 6 months and less than 2 years prior to screening, and/or
       • Have stable chronic graft-versus-host disease.

    4. Had a solid organ transplant or hematopoietic cell transplant more than 2 years prior to screening and may be eligible based on the inclusion criteria for immunosuppressive treatment.

    5. Is receiving immunosuppressive medicines (e.g., corticosteroids [i.e., at least 20 milligrams {mg} prednisone or equivalent per day], alkylating agents, antimetabolites, transplant-related immunosuppressive drugs, cancer chemotherapeutic agents classified as severely immunosuppressive [e.g., Bruton's tyrosine kinase inhibitors], tumor- necrosis blockers, or other immunosuppressive biologic agents [e.g., for rheumatic diseases]).

    6. Has received chimeric antigen receptor-modified T-cell therapy.

    7. Has received B-cell depleting therapies (e.g., rituximab, ocrelizumab, ofatumumab, alemtuzumab) within the 12 months prior to screening.

    8. Has a moderate or severe primary or secondary immunodeficiency.

    9. Has advanced or untreated human immunodeficiency virus (HIV) infection manifested by cluster of differentiation 4 (CD4) cell counts less than 350/cubic millimeter (mm^3) within 6 months of screening.

Exclusion Criteria

1. A female who is pregnant or lactating.
2. Known or suspected allergy or history of anaphylaxis or other serious adverse reactions to zanamivir (following administration of inhaled or intravenous formulations), monoclonal antibodies (including crystallizable fragment [Fc] domains), or any of the components of CD388 or placebo.
3. Has been diagnosed with influenza (i.e., with medical history [including verbal] of influenza) within 6 months prior to randomization.
4. Has received the current seasonal inactivated influenza vaccine or live attenuated influenza vaccine within the 14 days prior to dosing on Day 1. (NOTE: Participant may have received recombinant influenza vaccine but not within the 7 days prior to dosing on Day 1.)
5. Has an acute (time-limited) or febrile (temperature ≥38.0 degrees Celsius [ºC] [≥100.4 degrees Fahrenheit {ºF}]) illness within 7 days prior to planned dosing on Day 1.
6. Has had close contact (including household contact) with someone with laboratory-confirmed influenza or SARS-CoV-2 or with someone who has been treated with antiviral therapies for influenza or SARS-CoV-2 within the 7 days prior to randomization.
7. Has a clinically unstable condition including, but not limited to, a psychiatric condition, including recent (within the past year) or active suicidal ideation/behavior, or any other condition for which, in the opinion of the Investigator, may lead to hospitalization or death within the study period and that suggests that study enrollment would not be in the participant's best interest and/or that could prevent, confound, or limit the protocol-specified assessments.
8. Has any history of alcohol or drug abuse that, in the opinion of the Investigator, would adversely impact the conduct of the study.
9. Had major surgery (e.g., major cardiac, pulmonary or abdominal operation) within 4 weeks prior to randomization, or will not have fully recovered from surgery, or has major surgery planned during the time the participant is expected to participate in the study.
10. Has severe CKD (estimated creatinine clearance less than 30 mL/min using Cockcroft-Gault equation), and is not receiving hemodialysis.
11. Has screening electrocardiogram (ECG) findings of prolonged QT interval corrected using Fridericia's formula (QTcF) (greater than 450 milliseconds [msec] in males or greater than 470 msec in females), prolonged PR interval (greater than 220 msec), second- or third-degree heart block, or other clinically significant dysrhythmias, unless participant has a known cardiac diagnosis responsible for the ECG findings and is in stable condition. NOTE: Participants with cardiac pacemakers may be enrolled if no exclusion criteria are met.
12. Current or planned participation in another clinical study in which study intervention is being administered during participation in the current study. NOTE: Concurrent enrollment is allowed during the follow-up phase of the other clinical study or in case the study intervention in the other clinical study is a marketed product already approved for another indication - exception being if the other study requires study interventions that could affect the safety assessments of the present study (e.g., clinical laboratory tests).
13. Receipt within the past 30 days or 5 half-lives (whichever is longer) or anticipated receipt of any drug or other biologic agent (e.g., monoclonal antibodies) administered for the prevention or treatment of influenza.
14. Receipt of any formulation of immunoglobulin within 21 days of planned study intervention administration.
15. Receipt of any experimental drug, vaccine, or biologic agent within the 90 days or 5 half-lives (whichever is longer) prior to study intervention administration.
16. Has a clinically significant bleeding disorder (e.g., factor deficiency, coagulopathy, or platelet disorder) or medical history of significant bleeding or bruising following intramuscular or SQ injections or venipuncture. NOTE: Participants receiving apixaban or warfarin may be enrolled if the Investigator determines risk of SQ treatment with study intervention on Day 1 is minimal.
17. Has donated ≥450 mL of blood product (1 unit) for any reason within 30 days of screening.
18. Has direct involvement in the proposed study or other studies under the direction of the Investigator, sub-investigators, or at the study site; or is a family member of an individual with such direct involvement; or is an employee of the Sponsor.
19. In the Investigator's judgment, the participant has any condition or circumstance present that significantly increases risk, affects the ability to participate, impairs interpretation of study data, or indicates a likelihood of non-adherence to study requirements.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Percentage of Participants Experiencing Protocol-defined Influenza-like Illness (ILI) Occurring ≥7 Days after and up to 24 Weeks after Administration of Study Drug	From Day 8 up to 24 weeks after study drug dosing	Percentage of participants experiencing protocol-defined ILI occurring after administration of CD388, with influenza infection confirmed by a reverse-transcriptase polymerase chain reaction positive (RT-PCR+) result based on a nasopharyngeal (NP) swab assayed locally (first occurrence only), as compared to placebo.

Secondary Outcome Measures

Name	Time	Method
Incidence and Severity of Treatment-Emergent Adverse Events (TEAEs) after Administration of Study Drug	From Day 1 through Day 197/End of Study (EOS) after study drug dosing	Safety and tolerability of CD388, as compared to placebo, will be evaluated by assessing the number of participants with incidences of TEAEs following the administration of study drug. TEAEs include but are not limited to adverse events (AEs), serious adverse events (SAEs), injection site reactions (ISRs), and any potentially clinically significant changes from baseline seen in vital signs and clinical laboratory parameters.
Trough Plasma Concentration at 24 Weeks (C[trough24w]) Following Administration of CD388	Based on sampling done at onsite visits on Day 8 (±3 days), Day 29 (±3 days), and Day 197/EOS (±7 days)	Evaluation of the trough plasma concentration at 24 weeks (C\[trough24w\]) after study drug dosing.
Maximum Plasma Concentration (C[max]) Following Administration of CD388	At onsite visits done on Day 8 (±3 days), Day 29 (±3 days), and Day 197/EOS (±7 days)	Evaluation of the maximum plasma concentration (C\[max\]) after study drug dosing.
Area Under the Plasma Concentration-Time Curve (AUC) Following Administration of CD388	At onsite visits done on Day 8 (±3 days), Day 29 (±3 days), and Day 197/EOS (±7 days)	Evaluation of the area under the plasma concentration-time curve (AUC) after study drug dosing.
Detection of Anti-Drug Antibodies (ADAs) in Participants Administered CD388	On Day 1 (pre-dose baseline) and at onsite visits done on Day 29 (±3 days) and Day 197/EOS (±7 days)	Evaluation of blood serum samples for the detection of treatment-emergent anti-drug antibodies (ADAs) or treatment-boosted ADAs (based on an increase in ADA titer in samples positive for ADA at baseline) in participants administered CD388.

Trial Locations

Locations (15)

Pinnacle Research Group, LLC; 🇺🇸 Anniston, Alabama, United States

Stamford Therapeutics Consortium; 🇺🇸 Stamford, Connecticut, United States

Imagine Research - Palm Beach County; 🇺🇸 Boynton Beach, Florida, United States

South Florida Research Center, Inc.; 🇺🇸 Miami, Florida, United States

Healthcare Clinical Data, Inc.; 🇺🇸 North Miami, Florida, United States

Velocity Clinical Research - Omaha; 🇺🇸 Omaha, Nebraska, United States

Brooklyn Clinical Research; 🇺🇸 Brooklyn, New York, United States

West Clinical Research, Inc.; 🇺🇸 Morehead City, North Carolina, United States

Velocity Clinical Research - Cleveland; 🇺🇸 Beachwood, Ohio, United States

Velocity Clinical Research - Springdale; 🇺🇸 Cincinnati, Ohio, United States

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