San Francisco, April 6 : California-based biotechnology company Gilead Sciences is ready with 1.5 individual doses of promising remdesivir drug against COVID-19 disease for compassionate use, expanded access and clinical trials, its CEO has announced. Gilead said it is providing the existing supply at no cost, to treat patients with the most severe symptoms of COVID-19. "These doses are for treating patients with severe symptoms, through daily intravenous infusions in a hospital setting. Having a potential treatment in our hands comes with significant responsibility. Providing our existing supplies at no charge is the right thing to do," Daniel O'Day said in a blog post. Originally developed by Gilead to combat Ebola and related viruses, remdesivir shuts down viral replication by inhibiting a key viral enzyme, the RNA-dependent RNA polymerase. The first COVID-19 patient diagnosed in the US -- a young man in Snohomish County, Washington state -- was given remdesivir when his condition worsened and he improved the next day, according to a case report in the New England Journal of Medicine (NEJM). A Californian patient who received remdesivir recovered as well. According to Gilead CEO, more than 1,700 COVID-19 patients have now been treated through the company's programmes. "New US sites have been initiated and we are adding more on an ongoing basis. We are also making progress in Europe. The European Medicines Agency announced that it has provided EU member states with recommendations on implementing expanded access programmes for remdesivir in their countries," informed Daniel. Remdesivir is still an investigational medicine and has not been approved by regulatory authorities anywhere in the world. "The safety and efficacy are not yet known so while we feel the greatest sense of urgency in our work with remdesivir, we must take the responsible, ethical approach of determining whether it is indeed a safe, effective treatment. "This is why multiple clinical trials for remdesivir are underway, involving thousands of patients with COVID-19 across the world," said the CEO. Scientists have suggested dozens of existing compounds for testing but WHO is focusing on the four most promising therapies. These are "an experimental antiviral compound called remdesivir; the malaria medications chloroquine and hydroxychloroquine; a combination of two HIV drugs, lopinavir and ritonavir; and that same combination plus interferon-beta, an immune system messenger that can help cripple viruses". Gilead has reduced the end-to-end manufacturing timeline from approximately one year, to around six months. "We have set an ambitious goal of producing more than 500,000 treatment courses by October and more than 1 million treatment courses by the end of this year," informed the CEO. /IANS