Lessons learned from 5 years of pegvaliase in US clinics: A case series

To provide insights and strategies for pegvaliase management in challenging cases with phenylketonuria (PKU) based on the first 5 years of experience with pegvaliase in real-world clinical practice.

Twelve PKU experts gathered during a one-day, in-person meeting to discuss clinical cases illustrating important lessons from their experiences treating patients with pegvaliase in real-world clinical practice. Challenges with pegvaliase experienced prior to and during treatment and corresponding strategies to overcome them were discussed.

Twelve cases of adults with PKU (eight females and four males, aged 18 to 68 years) receiving pegvaliase were reviewed and discussed. Challenges of the cases included medical or mental health comorbidities, executive function deficits, challenging social or socioeconomic situations, logistical or geographic barriers, or a combination of these; one was considering pregnancy. Despite challenges, pegvaliase was initiated successfully in most cases. Strategies to overcome barriers included individualized education, including side effect action plans, help from support organizations, collaboration with local providers, and use of telemedicine. Recommendations from the clinicians included that comorbid conditions should be monitored closely after treatment initiation and may require collaboration with other healthcare providers. A collaborative relationship with the clinic, ongoing education, and supportive relatives or friends can help individuals to remain adherent to pegvaliase. Suboptimal adherence may be addressed by a daily reminder system, telemedicine, in-home support, or a modified titration plan. Treated individuals with eating disorders require additional follow-up and support to achieve a healthy relationship with food. In most cases, including late-diagnosed individuals, reduced blood Phe levels resulted in improved PKU-related symptoms, including neurological issues.

Experience from the presented cases and 5 years of expert experience with pegvaliase in the real-world setting provide insight and guidance for healthcare professionals initiating and managing pegvaliase treatment in complex PKU cases. These cases demonstrate that, through comprehensive assessment and addressing barriers, pegvaliase treatment can be successful in adults with PKU, regardless of prior treatment success, age, socioeconomic, cognitive, or executive function challenges, as well as in those with comorbidities or considering pregnancy. Ongoing documentation of clinical experience is crucial for advancing the management of individuals receiving this treatment.