Regulatory Focus™ > News Articles > 2019 > 11 > FDA Finalizes Smallpox Drug Development Guidance

FDA Finalizes Smallpox Drug Development Guidance

Posted 15 November 2019 | By Michael Mezher 

FDA Finalizes Smallpox Drug Development Guidance

The US Food and Drug Administration (FDA) on Friday finalized guidance on developing drugs to treat smallpox, clarifying aspects of a revised draft guidance released last year.
 
Just days after the revised draft guidance was released, FDA in July 2018 approved the first drug indicated to treat smallpox, Siga Technologies’ TPOXX (tecovirimat), which won the company a priority review voucher (PRV). In September the agency approved the first live, non-replicating smallpox and monkeypox vaccine, Bavarian Nordic’s Jynneos, which also won a PRV.
 
While smallpox was formally declared to be eradicated in the wild by the World Health Organization in 1980, FDA and other health officials around the world have expressed concerns that smallpox could be used as a biological weapon or in terrorist attacks.
 
“Despite recent advances in developing an effective treatment for smallpox, drug developers still face challenges in bringing forward these medical countermeasures, which are critical should smallpox ever be used as a biological weapon,” said FDA Deputy Commissioner for Policy, Legislation and International Affairs Anna Abram.
 
Among those challenges are the fact that there are no new naturally occurring cases of smallpox in the wild, lacking data on the pathophysiology of human smallpox, the restricted nature of variola virus samples and the “ethical issues that preclude human smallpox challenge studies.”
 
As such, FDA says that drugs developed to treat smallpox “should be developed and approved” under 21 CFR part 314, subpart I, commonly referred to as the Animal Rule.
 
According to FDA, the main changes made in the final guidance are clarifications regarding the “recommended immunological characterizations of animals in key studies.” The final guidance has also been revised for minor editorial changes.
 
Specifically, FDA says that sponsors should perform a direct serologic analysis for larger animals or indirect analyses for rodents “to monitor for any prior orthopoxvirus exposures in the test animals” and notes that “cellular immune assays should be considered when feasible and appropriate.”
 
FDA also instructs sponsors to consider the difference in time in disease development between humans and animal models when designing study protocols.
 
Some minor changes in the final guidance include an emphasis that the recommendations made within apply to monoclonal antibodies and a note that any study involving variola virus “must be conducted in collaboration with the CDC and will require approval from the World Health Organization.”
 
The guidance does not apply to other biological products or treatments intended to address bacterial complications from smallpox.
 
FDA, Guidance

Regulatory Focus newsletters

All the biggest regulatory news and happenings.

Subscribe