ImClone Systems Inc.'s huge co-development and co-promotion deal for IMC-C225 with Bristol-Myers Squibb Co. should provide comforting validation to product companies resisting the urge to cash in their chips too early in the game.

In IMCL's case, its bargaining chips were the fact that it held on to North American rights through the start of its rolling BLA submission, coupled with pressure on BMY to reburnish its cancer franchise.