Potential: An existing therapy for coronavirus may exist in the drugs Ritonavir or Hydroxychloroquine, both have been used in patients with mild coronavirus disease (COVID-19).
As for another therapy, Ciclesonide: "the National Institute of Infectious Diseases (NIID) reported that Ciclesonide was given to patients with the new coronavirus disease, COVID-19, after being found to have some effect in the treatment of Middle East Respiratory Syndrome (MERS), which is caused by another type of coronavirus. The drug is said to control inflammation and block multiplication of the virus. - The Mainichi
