If a drug, like Isoprinazine the anti-herpes drug, has been sold all over the world for 45 years, isn’t there enough safety and efficacy data to approve it after review by the FDA? It sought approval around 1980 and didn’t get it, even though the results were far more impressive that Acyclovir. The only known side effect is an increase in uric acid, so gout sufferers should avoid it. The substance is naturally occurring in the human body and acts as an immunopotentiator. I believe money and politics got in the way of approval.