The lipid aspect of the molecule takes on the action of endogenous lysophosphatidyl choline, which then is able to enter cells in the body which are infected with smallpox.

[3] Safety information to support approval of brincidofovir was derived from clinical trials of the drug for a non-smallpox indication, primarily from patients who received hematopoietic stem cell transplants.

[3] Brincidofovir (CMX001) was the subject of widespread social media campaigning in 2014, which was then picked up by national news sources about a boy with an adenovirus infection following a bone marrow transplant.

After a short and intense media campaign, Chimerix got permission from the FDA to start a limited open-label trial which allowed the boy to receive the drug.

The new use of any drug has the potential to interfere with the process to get the drug approved and widely marketed, through means such as consuming limited staff time that may be needed elsewhere – staff time that has the potential to save thousands of lives in the long-term, rather than one life now – overwhelming manufacturing capabilities, or by causing adverse effects or even death.

[12] Brincidofovir is one of several experimental drugs administered to a small number of patients to treat Ebola virus disease during the 2014 outbreak.

The WHO published a report on the ethics of using unregistered interventions to treat Ebola, where they concluded that "In the particular context of the current Ebola outbreak in West Africa, it is ethically acceptable to offer unproven interventions that have shown promising results in the laboratory and in animal models but have not yet been evaluated for safety and efficacy in humans as potential treatment or prevention.

[24] In October 2014, Chimerix reported it had been given approval by the FDA to start Phase 2 trials in patients infected with ebolaviruses for brincidofovir's safety, tolerability, and efficacy.

[25] Organised by a team of scientists at the University of Oxford, including Peter Horby, Jake Dunning, Laura Merson and Trudie Lang,[26] a trial commenced during January 2015 in Liberia,[27] but was subsequently discontinued.