I get that. What I don't get is why would a partner want MNTA fund 25% of phase 2b? I'd say either 50-50 or 100 either way (MNTA or partner) for phase 2b.
I would just say simply because if MNTA only funds 25%, as opposed to 50%, the partner would presumably craft the partnership agreement to ensure that it be entitled to much greater economics from the partnership. Assuming the partner can afford the extra cost, they would want to be entitled to a higher share of the ultimate economics from the drug.