My issue with waiting for P data to sell the company is that IPIX would likely have to turn down potential partnerships for B alone in hopes that P is good to sell the company. Or he tells the potential partners "I might do a B deal with you, but you have to wait x months before I decide". That gives the potential partner x months to change their mind, or get frustrated and walk away.
IF there are potential B deals on the table, I think the best decision would be to pick the best deal and sign it asap. But I don't work in the medical field or have a management position in any company, so what do I know...heck, I don't even know if there are any B deals on the table.