If SNY is not planning on launching a generic that appears to imply that they are confident about retaining a decent share of the US market. If they suspected that m-enox would capture around 80 % of the market it doesn't seem logical not to launch an AG.
If SNY stayed the course and took only a 20% share of the approximately 3B us market, that accounts for about 600 M. If they launched an AG and the AG had a discount of say 25% and captured 50% of the market then thats about 1.125 B minus licensing. Branded lovenox sales will probably be a negligible percentage.
So if SNY is not planing to launch an AG they are either assuming that they would retain about 40-50 % of the market. Is there any other logical reason for SNY to not launch an AG?