WASHINGTON, Dec 14 (Reuters) - U.S. President Joe Biden said on Tuesday he is encouraged by data released by Pfizer Inc (PFE.N) on its COVID-19 anti-viral medicine and his administration has ordered enough of the pills to treat 10 million Americans. "Getting vaccinated and getting your booster shot remain the most important tools we have to save lives. But if this treatment is indeed authorized — and once the pills are widely available — it will mark a significant step forward in our path out of the pandemic," Biden said in a statement.