BACKGROUND:Phenylketonuria (PKU) is an autosomal recessive disease caused by mutations in the PAH gene, resulting in deficiency of phenylalanine hydroxylase (PAH), an enzyme that converts phenylalanine (Phe) to tyrosine (Tyr). The purpose of this study was to capture real-world data associated with managing PKU under current standard of care and to characterize a representative population for a planned gene therapy trial. METHODS:A retrospective chart review was conducted at two U.S. clinics for individuals 10-40 years old diagnosed with PKU-related hyperphenylalaninemia (HPA). Demographics, medical history, treatments and blood Phe data were collected from electronic medical records spanning a five-year period ending in November 2017. RESULTS:152 patients were enrolled (65.8% had classical PKU). Although >95% of patients were prescribed a Phe-restricted diet, blood Phe concentrations remained substantially elevated, particularly in patients diagnosed with classical PKU. As the Phe threshold was lowered (Phe < 600, 360, 120 or 30 μmol/L), the number of patients with consecutive lab values below the threshold decreased, suggesting that many patients' Phe levels are inadequately controlled. 62.5% of patients were reported as having a history of at least one neuropsychiatric comorbidity, and adults were more likely than adolescents (69.5% vs. 54.3%). 92 of 98 PAH genotypes collected were distinct mutations; the 6 null-null genotypes were associated with classical PKU. Overall the demographics and clinical data were consistent across both sites. CONCLUSION:Despite dietary restrictions, mean Phe concentrations were > 360 μmol/L (a level considered well-controlled based on current U.S. treatment guidelines) for mild, moderate, and classical PKU patients. There remains an unmet need for therapies to control Phe concentrations.

Background: The KAST (Kiva Safety and Efficacy) investigation device exempt (IDE) study indicated that the majority of patients responded equally well to vertebral augmentation using either an implantbased approach or balloon kyphoplasty (BK). Additional investigation has suggested that a subset of patients may benefit further by avoiding repeated readmissions due to serious adverse events (SAEs) if they receive one vertebral augmentation approach over another. Objectives: The primary aim was to assess the effect of 2 different augmentation procedures on readmission rates for SAEs. Study Design: The KAST trial is a pivotal, multicenter, randomized, controlled trial conducted to evaluate an implant-based vertebral augmentation approach (implant) against BK. Post-hoc analysis was performed to evaluate SAEs and readmission rates. Setting: Twenty-one sites in North America and Europe. Methods: The treatment effect of vertebral implant versus BK on SAEs requiring unplanned readmission was evaluated by estimating the risk of SAEs associated with readmissions in KAST while controlling for key baseline covariates using multivariate Poisson regression modeling. Results: Forty (27.8%) patients with implants had 69 SAEs associated with readmission compared to 44 (31.2%) patients with BK having 103 events. The risk for all SAEs leading to readmission was 34.4% lower with the implant than for BK (95% confidence interval = 11.1%, 51.7%; P < 0.01). Multivariate analysis showed that the risk of SAEs associated with readmission was decreased in subjects treated with the implant compared to BK, and increased in patients with prior histories of vertebral compression fractures (VCFs) or significant osteoporosis. Limitations: The power of the KIVA study was based on clinical efficacy criteria to meet FDA requirements and recommendations for equivalency or noninferiority. The primary endpoint in this posthoc analysis is SAEs associated with readmissions; as a result, the sample size is underpowered, although the results remain significant. Conclusion: The augmentation approaches compared here have similar pain relief and quality of life effects; the implant showed a lower risk of readmissions.

BACKGROUND CONTEXT: Vertebral compression fractures (VCFs) are costly, with expenditures exceeding a billion dollars annually in the United States. The effectiveness of different vertebral compression fracture treatment approaches for preventing re-admissions associated with VCFs or other related conditions is important to assess.