Koo, 

It may be related to Denali's deal with F-star on the Antibody Transport Vehicle (ATV). From what I understand, the Denali/F-star first Fcab targeted transferrin receptor. But sounds like they are expanding the work to cover two more undisclosed transporter targets. 

https://endpts.com/after-tracking-success-in-animals-neurosciences-star-denali-moves-early-to-bag-an-option-on-a-promising-tech-for-crossing-the-blood-brain-barrier/