Please tell us about your clinical experience. How many patients with PKU do you see on a yearly basis? How many of them have an aggravated level of the disease? How many of them do you diagnose as newborns?

What is the standard of treatment for PKU patients? What is the optimal range of phenylalanine that you aim for in your patients and how do you achieve that?

How big of an impact does diet make in the outcome of this disease? Do your patients take tyrosine or casein glycomacropeptide supplements, besides their drug treatments?

What can you tell us about Rubius’ red blood cell engineering, do you believe a method like this could work in PKU, can it be brought to market?

What are the fundamental differences between RTX-134 and Pegvaliase (Palynziq)? Is Rubius’ choice to deliver the enzyme phenylalanine ammonia lyase through red blood cells more efficient than Biomarin’s pegylated derivative via injection?

Have you used Pegvaliase in your patients since its approval in May 2018? What feedback can you give us on its safety and efficacy, as compared to previous therapies?

What can you tell us about Biomarin's Phase 2 PEG-PAL gene therapy? Does it have the potential to become important in the PKU space? What are the pros and cons of it so far?

What advantages, if any do you think RTX-134 has over other therapies (sapropterin, pegvaliase, etc). If approved, how likely would you be to switch patients?

Does the fact that Rubius’ RCTs lack a nucleus increase tolerability, compared to other cellular therapies? What is the risk of the cells continuing to divide, expand and differentiate uncontrollably, post-injection?

Given that RBCs have a circulating time of approximately 120 days, what would a dosing schedule look like? Would the patient require frequent check-ups due to the unpredictable pharmacokinetics and biodistribution associated with cellular therapies?