No serious buyout offers until FDA approval. Common method is to value all future earnings into current value. Discount for risk of realizing those earnings. I'd say lowball of $5B. NP would be nuts to walk away from $10B. Likely a part cash / part shares of the acquiring Company to sweeten the pot for long time investors to vote yes.
Justification would be faster rollout of miracle drug if done by a big established pharma.