Two Ebola patients in the United States are receiving experimental therapy initially developed to treat other viral infections.

The drug, called brincinofovir, is made by Chimerix, Inc, a Durham, N.C.-based biotechnology company that became somewhat of a household name back in March when a social media campaign petitioned for “compassionate use” of the drug to treat an 8-year-old cancer patient with a life-threatening viral infection after a bone marrow transplant at St. Jude’s Children’s Hospital.

The patient, Josh Hardy, was suffering from adenovirus – a common infection that often causes respiratory illness –  that he developed while his immune system was suppressed after the transplant. The current standard therapy for patients like Josh, cidofovir, had compromised his kidney function past the point of what his small body could tolerate.

The drug was still in phase III clinical trials at the time, being used to treat cytomegalovirus – a common infection that can be quite dangerous in pregnant women or those with compromised immune systems – and the company stood to lose years of vital clinical data by allowing for its use outside of the controlled environment. Thankfully, Chimerix heard the pleas of the many Americans petitioning them to “Save Josh,” and agreed to give the boy the drug. Months later, in July, Josh was well enough to leave the hospital and return home to Virginia.

Brincinofovir is still in the experimental phase, but it was approved by the Food and Drug Administration (FDA) on Monday for the treatment of Ebola, according to a statement from Chimerix. The drug is a stronger, longer-lasting version of other antivirals in its class, which was specifically designed for use against a bioterrorism attack with smallpox.

I am cautiously optimistic about the potential efficacy of this drug, for the treatment of these two Ebola patients in America, particularly because it has done well in phase III clinical trials. The drug has been used on 900 patients to date in large-scale human trials for the treatment of adenovirus and CMV, and received “fast-track” designation from the FDA for the treatment of smallpox as well. Until now, the drug has never been used in human Ebola patients, but test-tube studies have shown promise and studies are currently underway in animals with the disease.

The one caveat in this whole equation is the fact that the viruses in which the efficacy of brincinofovir have been studied are double-stranded DNA viruses, whereas Ebola is a single-stranded RNA genome. But looking at the genomics of Ebola, this drug may have some effect. The problem, of course, lies in the fact that our knowledge is limited since we do not have clinical data to draw on when it comes to Ebola. Yet, under the current circumstances, it’s important for the Centers for Disease Control and Prevention (CDC) as well as Chimerix, to use every possible effort to create expeditious trials and monitor outcomes. If the experimental therapies and current trials yield positive results, they must work fast on the potential for distribution to West Africa.

I know that ethical dilemmas will always be encountered when it comes to drug trials, but the world is in a crisis right now, and we need to act fast.

Dr. Manny Alvarez serves as Fox News Channel's senior managing health editor. He also serves as chairman of the department of obstetrics/gynecology and reproductive science at Hackensack University Medical Center in New Jersey. Click here for more information on Dr. Manny's work with Hackensack University Medical Center. Visit AskDrManny.com for more.