The two sides have reached an impasse, with Genzyme insisting that Sanofi raise its offer to begin discussions, and Sanofi maintaining that, in the absence of any white knight, it will not "bid against itself." A look at Genzyme's books, a customary prerequisite for an acquirer, is particularly important in this case, given highly publicized manufacturing glitches at Genzyme. Mr. Viehbacher has in the past indicated that, if it were able to make such an examination, Sanofi would be willing to raise its offer by an unspecified amount.