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Enanta applies its chemistry-driven approach and drug discovery capabilities to developing small molecule cures for viral infections and immunological diseases where there is significant high unmet need. We are committed to ‘reaching high’ on behalf of the most at-risk patients. Through our collaboration with AbbVie, we helped discover two cures for hepatitis C and today have novel, potential cures at the development stage for infections of respiratory syncytial virus (RSV), SARS-CoV-2 and hepatitis B virus. Currently we have two ongoing Phase 2 trials for zelicapavir (EDP-938), a treatment in development for high-risk patients with RSV. To learn more about participation in Enanta clinical trials, please see below.

Clinical Trials

Enanta is committed to the development of novel treatments for viral infections for patients with serious medical conditions. Enanta has active clinical trial programs in respiratory syncytial virus (RSV).

If you are interested in learning more about Enanta’s current and future clinical trials, please contact:

Through clinical trials we are advancing novel therapeutics for significant respiratory infections.

Respiratory Syncytial Virus

Expanded Access Policy

At Enanta, we are dedicated to discovering and developing safe and efficacious treatments for life-threatening viral infections. We understand the significant impact serious viral infections can have on patients and their caregivers. We are committed to making our therapies available to as many patients as possible, as safely and quickly as is feasible.

Our ongoing clinical trial programs, used to support regulatory approval, are the most effective way to access an Enanta investigational medication. Enanta encourages patients to speak with their treating physicians about participating in a clinical trial, when possible. You can find additional information about Enanta’s ongoing clinical trials on our website or by accessing

We understand that, in some cases, patients may not be eligible for clinical trials and do not have other treatment options. When enrollment into a clinical trial is not an option, and where all currently available treatment options have been exhausted, an investigational medicine may be provided prior to regulatory approval or commercial availability, under a provision referred to as “Expanded Access” by the U.S. Food and Drug Administration (FDA).

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Per FDA, Expanded Access may be appropriate when all of the following apply:

  • Patient has a serious or immediately life-threatening disease or condition.
  • There is no comparable or satisfactory alternative therapy to diagnose, monitor, or treat the disease or condition.
  • Patient enrollment in a clinical trial is not possible.
  • Potential patient benefit justifies the potential risks of treatment.
  • Providing the investigational medical product will not interfere with investigational trials that could support a medical product’s development or marketing approval for the treatment indication.

At this time, Enanta will make its investigational medicines available on an Expanded Access basis prior to regulatory approval, if the above conditions apply, as well as the following criteria are met:

  • Adequate clinical data exist to support the appropriate dosing regimen of the investigational medicine and duration of treatment in the disease or condition.
  • The company has an adequate supply of the investigational product to meet the needs of the expanded access program without impairing ongoing development, including ongoing and planned clinical trials.
  • It should be logistically feasible for the company to provide the patient with the investigational drug.
  • The requested use complies with applicable laws and regulations.

All requests for Expanded Access must come from a patient’s treating physician and will be evaluated by a multidisciplinary team and responded to on a case-by-case basis. Qualified and licensed physicians may make such requests at We target acknowledging receipt of requests as soon as possible and in most cases within two (2) business days. The requesting physician must agree to obtain appropriate regulatory and ethics committee approvals, and to comply with all other regulatory, safety, monitoring, and patient consent requirements.

Early access may be discontinued when approval of the drug is achieved in the patient’s country, subject to any legal or regulatory requirements. Similarly, expanded access may be discontinued if the benefit of treatment does not outweigh the risk or if any of the original required criteria are no longer met.

Enanta may revise this Expanded Access Policy at any time. The posting of this policy by Enanta shall not serve as a guarantee of access to any specific investigational medicine by any individual patient. 

Patient Resources

Respiratory Syncytial Virus (RSV)

American Lung Association logo
American Thoracic logo
CDC logo
healthy children dot org logo
National Foundation for Infectious Diseases logo


CDC logo

Hepatitis B Virus (HBV)

CDC logo
Hepatits B Foundation logo
Hep B United dot org logo
World Hepatitis Alliance logo