Its really simple. Linda wanted to have a backup retirement plan if DCVAXL were to be denied approval. A gigantic put option if you will.
That put option is called Advent, which will still retain its immense value IF DCVAXL were to be denied approval (which I do not believe, I strongly believe DCVAXL will be approved, but that's not the subject).
Linda's Put option has cost at least $250 million in shareholders' value and 4000 GBM patients' lives.
And thats not taking into account the opportunity costs of starting other cancer trials with that money that has now been poured into Advent. Great going, Linda.