Blood Phenylalanine (Phe) Levels in Individuals With Phenylketonuria (PKU): A United States Electronic Health Records (US EHR) and Medical Notes Study
Author(s)
Nicola Longo, MD, PhD1, Rongrong Zhang, MSc2, Hope Northrup, MD3, Suzanne Hollander, MD4, Neil Smith, PharmD5, Kim Ingalls, MD5, Alexis Krolick, DNO5, Hanaya Raad, MPH, PharmD6, Stefano Tagliabue, MSc6, Gregoire Nowacki, MSc6, John Karafilidis, PharmD5, Ioannis Tomazos, MBA, PhD5.
1Division of Clinical Genetics, University of California Los Angeles, Los Angeles, CA, USA, 2PTC Therapeutics Sweden AB, Askim, Sweden, 3University of Texas Health Science Center at Houston, Houston, TX, USA, 4Boston Children’s Hospital, Boston, MA, USA, 5PTC Therapeutics, Inc, Warren, NJ, USA, 6Oracle Life Sciences, Paris, France.
1Division of Clinical Genetics, University of California Los Angeles, Los Angeles, CA, USA, 2PTC Therapeutics Sweden AB, Askim, Sweden, 3University of Texas Health Science Center at Houston, Houston, TX, USA, 4Boston Children’s Hospital, Boston, MA, USA, 5PTC Therapeutics, Inc, Warren, NJ, USA, 6Oracle Life Sciences, Paris, France.
Presentation Documents
OBJECTIVES: PKU management requires a Phe-restricted diet and pharmacological therapies to reduce high blood Phe levels. This study describes real-world clinical characteristics and treatment patterns of individuals with PKU in the US.
METHODS: Individuals with PKU were identified from Oracle EHR by International Classification of Diseases-10 codes; medical notes were also reviewed to confirm diagnosis, understand treatment patterns, and clinical picture. The study period (01/APR/2015-31/DEC/2023) encompassed a 180-day pre-index baseline period, index date (i.e., date of first recorded PKU diagnosis), and ≥1 year(s) follow-up. Outcomes included treatment patterns, Phe levels, and clinical characteristics.
RESULTS: Of N=4,614 identified, 500 individuals with robust data were randomly selected for analysis. Mean (standard deviation [SD]) age was 16.5 (17.7) years; 47% were male. Overall, 36% (n=181) of individuals received sapropterin, 8% (n=42) received pegvaliase, 44% (n=221) received diet alone, and 11% (n=56) had no recorded intervention. Sapropterin was discontinued in 44% (79/181) and pegvaliase discontinued in 38% (16/42) of individuals. Proportion of individuals with blood Phe >360 µmol/L as the most frequently reported value during follow-up increased with age: 20% (28/138) among 0-4 years, 50% (36/72) among 5-11 years, 58% (37/64) among 12-17 years, 69% (83/120) among ≥18 years. Differences in annual average Phe levels between age groups were statistically significant, with older individuals having higher annual average blood Phe. More blood Phe tests were conducted for younger (mean [SD]: 17.1 [25.1] samples/year, age <5 years) compared to older individuals (4.6 [5.4] samples/year, age ≥18 years).
CONCLUSIONS: This study demonstrated that individuals with PKU continued to have Phe levels above target therapeutic range despite receipt of current diet and pharmacological therapies; elevated blood Phe was reported more frequently as age increased. Moreover, high rates of discontinuing pharmacologic treatment were observed. These findings highlight that novel PKU therapies are crucial to control Phe levels and address unmet needs.
METHODS: Individuals with PKU were identified from Oracle EHR by International Classification of Diseases-10 codes; medical notes were also reviewed to confirm diagnosis, understand treatment patterns, and clinical picture. The study period (01/APR/2015-31/DEC/2023) encompassed a 180-day pre-index baseline period, index date (i.e., date of first recorded PKU diagnosis), and ≥1 year(s) follow-up. Outcomes included treatment patterns, Phe levels, and clinical characteristics.
RESULTS: Of N=4,614 identified, 500 individuals with robust data were randomly selected for analysis. Mean (standard deviation [SD]) age was 16.5 (17.7) years; 47% were male. Overall, 36% (n=181) of individuals received sapropterin, 8% (n=42) received pegvaliase, 44% (n=221) received diet alone, and 11% (n=56) had no recorded intervention. Sapropterin was discontinued in 44% (79/181) and pegvaliase discontinued in 38% (16/42) of individuals. Proportion of individuals with blood Phe >360 µmol/L as the most frequently reported value during follow-up increased with age: 20% (28/138) among 0-4 years, 50% (36/72) among 5-11 years, 58% (37/64) among 12-17 years, 69% (83/120) among ≥18 years. Differences in annual average Phe levels between age groups were statistically significant, with older individuals having higher annual average blood Phe. More blood Phe tests were conducted for younger (mean [SD]: 17.1 [25.1] samples/year, age <5 years) compared to older individuals (4.6 [5.4] samples/year, age ≥18 years).
CONCLUSIONS: This study demonstrated that individuals with PKU continued to have Phe levels above target therapeutic range despite receipt of current diet and pharmacological therapies; elevated blood Phe was reported more frequently as age increased. Moreover, high rates of discontinuing pharmacologic treatment were observed. These findings highlight that novel PKU therapies are crucial to control Phe levels and address unmet needs.
Conference/Value in Health Info
2025-05, ISPOR 2025, Montréal, Quebec, CA
Value in Health, Volume 28, Issue S1
Code
CO177
Topic
Clinical Outcomes
Topic Subcategory
Clinical Outcomes Assessment
Disease
SDC: Rare & Orphan Diseases