Local biotech CEO says he was left with no options but to sue another company on whose board he once served

John Maraganore, CEO of Alnylam in Cambridge, is suing a Maryland biotech company for allegedly eliminating the stock options he got while serving on its board of directors before it went public.

In his suit against MacroGenics, filed yesterday in US District Court in Boston, Marganore says MacroGenics's CEO told him his stock options would not expire until 2016 when he stepped down from that company's board in 2009, as long as he stayed on as a consultant.