FDA Issues Revised Draft Guidance on Hepatitis C Drug Development

The US federal government may have been shut down, but that didn't stop the US Food and Drug Administration (FDA) from releasing a new guidance document on 16 October 2013 detailing its preferred methods of developing applications in support of drugs to treat chronic infections caused by the hepatitis C virus.

Background

FDA has been rather active in the hepatitis C drug development space in recent years. In 2009, it issued a final guidance document, Guidance on Antiviral Product Development-Conducting and Submitting Virology Studies, which was intended to assist in the development of new antivirals by establishing the data which are essential to submitting a successful regulatory application.

In February 2013, FDA released a document known as a guidance "attachment"-a short, three-page basic outline explaining how data submitted to the agency should be formatted.

In its latest guidance, Chronic Hepatitis C Virus Infection: Developing Direct-Acting Antiviral Drugs for Treatment, FDA seeks to promote clarity for developers of direct-acting antiviral (DAA) drugs. Such drugs are defined as those that disrupt the replication cycle of the virus directly (i.e. not indirectly, such as immune-system boosting products).

Fast-Changing Space

The last iteration of the guidance was published in September 2010, but regulators observed that the rapid development of therapies in the space necessitated further clarification. FDA notes that significant changes to the current guidance include:

• details on phase 2 and phase 3 trial design options for the evaluation of IFN-free and IFN-containing regimens in treatment-naïve and treatment-experienced populations, including DAA-experienced populations. For example, FDA notes that sustained virologic response (SVR) should be detectable through weeks four or twelve before phase III clinical testing should begin.
• revised primary endpoint to sustained virologic response at 12 weeks post-treatment cessation
• greater emphasis on DAA drug development in specific populations including trial design options for human immunodeficiency virus (HIV)/HCV co-infected subjects, subjects with decompensated cirrhosis, and subjects pre- or post-liver transplant
• more details on clinical virology considerations for DAA drugs

Due to ongoing advancements-there are "substantial scientific advancements announced at every major liver disease meeting," according to FDA-regulators also advised sponsors to reach out to FDA's Division of Antiviral Products (DAVP) during the pre-investigational new drug consultation (pre-IND) stage regarding scientific advancements that affect their respective drug development programs.

The draft guidance has not yet been published in the Federal Register, but industry will likely have 60-90 days in which to comment when it is eventually published.

Chronic Hepatitis C Virus Infection: Developing Direct-Acting Antiviral Drugs for Treatment