** Drug developer Eton Pharmaceuticals' ETON.O shares fall 2.2% to $13.39
** Company posts fourth-quarter net loss of 2 cents per share vs analysts' estimate of break even per share, according to data compiled by LSEG
** Company reports product revenue of $11.65 million vs est $10.53 million
** As of last close, Eton Pharma's shares have more than tripled in the past 12 months
(Reporting by Siddhi Mahatole)
((siddhi.mahatole@thomsonreuters.com))