These two antiviral drugs, known as ribavirin and interferon-alpha, cause flu-like
side effects including nausea, diarrhea and muscle achiness. The introduction of new drugs from Merck and Vertex Pharmaceuticals in 2011 helped shorten the treatment period and boost cure rates as high as 75 percent.
Olysio appears to be slightly more effective than the standard of care, curing 80 percent of patients who had not previously been treated for the disease, according to studies submitted to the FDA.