The Food and Drug Administration on Friday approved what is being called the most expensive drug in the world. Novartis’ Zolgensma is a one-time injection used to treat children with spinal muscular atrophy at a cost of $2.13 million, reports CNBC. If left untreated, the condition leads to loss of muscle function. Severe cases can result in death. Current treatments for the disease require regular infusions costing $750,000 in the first year and $375,000 per year thereafter.