They clearly cannot bring a PCS product to market themselves, so internal investment in that program takes away from funding for rare disease programs that could actually be taken to NDA alone, such as TTR.
This makes sense but moving the unpartnered program into phase 2 would instill investor confidence not only in the drug but in MC3 delivery.
MC3 appears to be pretty good, but clearly other new advances have outperformed it in preclinical models.