EDP-323 for Respiratory Syncytial Virus

Overseen By Chris Harris

Age: 18+

Sex: Any

Trial Phase: Phase 1

Sponsor: Enanta Pharmaceuticals, Inc

Must not be taking: Tobacco, Alcohol, others

Disqualifiers: Pregnancy, Heart disease, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

Duration: Varies depending on study part

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to understand how EDP-323, an experimental treatment, interacts with certain drugs in the body. It focuses on healthy individuals who wish to assist researchers in learning more about treating respiratory syncytial virus (RSV), a common virus that can cause serious lung issues. Participants will take EDP-323 alongside one of four other drugs—itraconazole, carbamazepine, quinidine, or fluconazole—to observe their interactions. This trial suits healthy individuals who do not smoke and have not been sick recently. As a Phase 1 trial, the research focuses on understanding how the treatment works in people, offering participants the opportunity to be among the first to receive this new treatment.

Do I need to stop my current medications for this trial?

The trial does not specify if you need to stop taking your current medications. However, since the study involves assessing the effect of certain drugs on EDP-323, it's possible that some medications might need to be paused. Please consult with the trial coordinators for specific guidance.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research shows that EDP-323 is generally safe and well-tolerated. Earlier studies found EDP-323 to be safe and effective, reducing the virus in the body by 85-87%. This indicates it works well against the virus with minimal side effects.

The study aims to examine how EDP-323 interacts with other drugs like itraconazole, carbamazepine, quinidine, and fluconazole. EDP-323 itself has already been shown to be safe, which can reassure those considering joining the trial, as it indicates prior testing confirmed its safety. ^{1 2 3 4 5}

Why are researchers excited about this trial's treatments?

Researchers are excited about EDP-323 for respiratory syncytial virus (RSV) because it offers a novel approach compared to current treatments like ribavirin and palivizumab. While most existing options focus on symptom management or prevention, EDP-323 could potentially target the virus more directly, offering a different mechanism of action. This investigational drug is being studied for its interactions with other medications like quinidine, fluconazole, carbamazepine, and itraconazole, which might help optimize its effectiveness and safety profile. This tailored interaction study could pave the way for more personalized and effective RSV treatments.

What evidence suggests that this trial's treatments could be effective for Respiratory Syncytial Virus?

Research has shown that EDP-323 is promising in fighting respiratory syncytial virus (RSV). Studies have found that EDP-323 can significantly reduce RSV symptoms, with a 66% to 78% decrease in symptom severity compared to a placebo. It also achieved an 85-87% reduction in the virus's presence in the body. EDP-323 targets a part of the virus that aids in its reproduction. This trial will explore EDP-323's interactions with other medications, such as quinidine, fluconazole, carbamazepine, and itraconazole, to further understand its potential as an effective RSV treatment. ^{1 3 6 7 8}

Who Is on the Research Team?

Enanta Pharmaceuticals, Inc

Principal Investigator

Enanta Pharmaceuticals, Inc

Are You a Good Fit for This Trial?

This trial is for healthy adults who can participate in a study to understand how certain drugs affect the body's handling and safety of EDP-323, which is being investigated for Respiratory Syncytial Virus. Specific eligibility criteria are not provided.

Inclusion Criteria

I will use two effective birth control methods during and 30 days after the trial.

I am a man who will use contraception during and up to 90 days after the study.

An informed consent document signed and dated by the subject

Exclusion Criteria

Participation in a clinical trial within 28 days prior to the first dose of study drug

Current tobacco smokers or use of tobacco within 3 months prior to Screening

I haven't had a fever or active infection in the last 7 days.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive EDP-323 in combination with either itraconazole, carbamazepine, quinidine, or fluconazole on respective dosing days

Varies depending on study part

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• EDP-323

Trial Overview The study investigates how itraconazole, carbamazepine, quinidine, and fluconazole each alter the pharmacokinetics (how the body processes) and safety of EDP-323 when taken by healthy individuals.

How Is the Trial Designed?

Group I: EDP-323 and quinidine interaction (Part 3) Experimental Treatment 2 Interventions

Subjects will receive EDP-323 and quinidine on respective dosing days

Group II: EDP-323 and itraconazole interaction (Part 1) Experimental Treatment 2 Interventions

Subjects will receive EDP-323 and itraconazole on respective dosing days

Group III: EDP-323 and fluconazole interaction (Part 4) Experimental Treatment 2 Interventions

Subjects will receive EDP-323 and fluconazole on respective dosing days

Group IV: EDP-323 and carbamazepine interaction (Part 2) Experimental Treatment 2 Interventions

Subjects will receive EDP-323 and carbamazepine on respective dosing days

Who Is Running the Clinical Trial?

Enanta Pharmaceuticals, Inc

Lead Sponsor

Trials

42

Recruited

3,200+

Published Research Related to This Trial

In a trial involving 43 infants at risk for RSV, the monoclonal antibody SB 209763 showed a good safety profile with only a few adverse events related to the drug, indicating it is generally safe for use in this population.

While SB 209763 demonstrated some ability to increase neutralization and fusion inhibition titers, it did not significantly reduce the incidence of RSV infections compared to placebo, suggesting that higher doses may be needed for effective protection against RSV lower respiratory tract disease.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety and pharmacokinetics of an intramuscular monoclonal antibody (SB 209763) against respiratory syncytial virus (RSV) in infants and young children at risk for severe RSV disease. Meissner, HC., Groothuis, JR., Rodriguez, WJ., et al.[2020]

EDP-938 is a promising new antiviral drug that effectively inhibits respiratory syncytial virus (RSV) replication, showing strong activity against various RSV strains with low effective concentrations (EC50s) in human bronchial epithelial cells.

It works by targeting a specific step in the viral life cycle and has a higher barrier to resistance compared to other antiviral drugs, making it a potentially robust treatment option, as demonstrated by its efficacy in a non-human primate model.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

EDP-938, a novel nucleoprotein inhibitor of respiratory syncytial virus, demonstrates potent antiviral activities in vitro and in a non-human primate model. Rhodin, MHJ., McAllister, NV., Castillo, J., et al.[2021]

In a phase 2a trial involving 178 participants, EDP-938 significantly reduced RSV viral load and total symptom scores compared to placebo, indicating its efficacy as a treatment for RSV infection.

All dosing regimens of EDP-938 demonstrated a safety profile similar to placebo, suggesting that it is a safe option for treating RSV without major side effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

EDP-938, a Respiratory Syncytial Virus Inhibitor, in a Human Virus Challenge. Ahmad, A., Eze, K., Noulin, N., et al.[2023]

In a study involving 69 participants, the fusion inhibitor JNJ-53718678 significantly reduced RSV viral load and clinical symptoms compared to placebo, indicating its potential as an effective treatment for RSV infection.

All doses of JNJ-53718678 (75 mg, 200 mg, and 500 mg) demonstrated a reduction in the duration of viral shedding and overall symptom severity, although some participants experienced mild adverse events.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Antiviral Activity of Oral JNJ-53718678 in Healthy Adult Volunteers Challenged With Respiratory Syncytial Virus: A Placebo-Controlled Study. Stevens, M., Rusch, S., DeVincenzo, J., et al.[2019]

The study found that the current AAP guidelines for administering palivizumab, a medication for RSV prophylaxis, may not adequately prioritize infants at the highest risk for hospitalization due to RSV, as some higher-risk infants receive fewer injections than lower-risk infants.

There are discrepancies between the AAP guidelines and existing literature regarding the risk of hospitalization for RSV based on gestational age and severity of lung disease, suggesting that the guidelines need to be revised to better align with the actual risk levels.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Guidelines for palivizumab prophylaxis: are they based on infant's risk of hospitalization for respiratory syncytial viral disease? Elhassan, NO., Stevens, TP., Sorbero, ME., et al.[2015]

EDP-938, a second-generation antiviral drug for respiratory syncytial virus (RSV), has shown high efficacy in reducing viral load in the lower respiratory tract during early human trials.

The drug is rapidly absorbed after oral administration, with a half-life of 11-18 hours, and administration of up to 600 mg/day for seven days resulted in minimal significant adverse effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[EDP-938, a new antiviral with inhibitory activity against the nucleoprotein of the respiratory syncytial virus]. Reina, J., Iglesias, C.[2023]

Two novel compounds, P13 and C15, were identified as effective inhibitors of human respiratory syncytial virus (RSV) in HEp-2 cell cultures, with IC₅₀ values of 0.11 and 0.13 μM, respectively, indicating strong antiviral activity.

Both compounds require presence during virus entry and cell-to-cell transmission to inhibit RSV, but they do not kill the virus directly or prevent its attachment, and their use can lead to the rapid emergence of drug-resistant viral variants.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Two novel fusion inhibitors of human respiratory syncytial virus. Lundin, A., Bergström, T., Bendrioua, L., et al.[2010]

Citations

1. ir.enanta.com ir.enanta.com/news-releases/news-release-details/enanta-pharmaceuticals-presents-new-data-zelicapavir-its-n

Enanta Pharmaceuticals Presents New Data for Zelicapavir ... These data suggest that EDP-323 is highly effective in preventing RSV infection when initiated up to 5 days after RSV exposure and further ...

2. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC12036344/

EDP‐323, a First‐In‐Class, Once‐Daily, Oral L‐Protein ... EDP-323 is a first-in-class, potent oral selective non-nucleoside inhibitor of the large protein (L polymerase) of RSV under investigation for the treatment of ...

3. clinicaltrials.gov clinicaltrials.gov/study/NCT06170242

NCT06170242 | A Controlled Phase 2a Study to Evaluate ... This study is designed to assess the antiviral effect of EDP-323 compared to a placebo control in the respiratory syncytial virus challenge model.

4. clinicaltrialsarena.com clinicaltrialsarena.com/analyst-comment/idweek-2025-enanta-edp-323-rsv/

IDWeek 2025: Enanta's EDP-323 rapidly reduces RSV viral ... EDP-323 reduced mean total symptom AUC by 66% in the high-dose group and 78% in the low-dose group compared with placebo (p<0.0001 for both).

5. ir.enanta.com ir.enanta.com/news-releases/news-release-details/enanta-pharmaceuticals-announces-positive-topline-results-edp

Press Release Details - Investors - Enanta Pharmaceuticals These data demonstrated that EDP-323 was generally safe and well-tolerated and achieved an 85-87% reduction in viral load area under the curve (AUC) by qRT-PCR.

6. clinicaltrials.gov clinicaltrials.gov/study/NCT06847464

NCT06847464 | A Drug-Drug Interaction Study to Evaluate ... The primary aim of the study is to assess the effect of itraconazole, carbamazepine, quinidine, and fluconazole individually on the pharmacokinetics and safety ...

7. go.drugbank.com go.drugbank.com/indications/DBCOND0079390/clinical_trials/DB00564?phase=1&status=completed

Respiratory Syncytial Virus (RSV) Infection A Drug-Drug Interaction Study to Evaluate the Effects of Itraconazole, Carbamazepine, Quinidine and Fluconazole on the Pharmacokinetics and Safety of EDP-323.

8. withpower.com withpower.com/trial/phase-1-infections-respiratory-syncytial-virus-2025-943b8

EDP-323 for Respiratory Syncytial Virus · Info for Participants In a trial involving 43 infants at risk for RSV, the monoclonal antibody SB 209763 showed a good safety profile with only a few adverse events related to the ...