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OBJECTIVES/GOALS: Diagnostic odyssey is the time it can take to a patient for receiving a diagnosis. Diagnostic process in rare diseases can be complex due to the heterogeneity of symptoms and lack of access to care. We aim to evaluate the association between diagnostic odyssey, perceived stress, and access to care, in parents of Puerto Rican patients with a rare disease. METHODS/STUDY POPULATION: We propose a cross-sectional study in parents of 100 children who received an uninformative whole exome sequencing (WES) report during a scheduled appointment with their geneticist. Discussion of WES results during clinical session, followed by a Perceived Stress Scale (PSS-10) and semi-structured interview to explore the experience of access to care during the diagnostic process will be arranged. Observation and interviews will be recorded. Data analysis and descriptive statistics will be calculated using STATA. Statistical associations (OR) will be estimated using generalized linear models at a 5% significance level. RESULTS/ANTICIPATED RESULTS: We expect to find high perceived stress in parents of Puerto Rican pediatric individuals having rare diseases, especially among single mothers. We will be able to identify limited access to care in Puerto Rico, especially in the testing pre-authorization process and long waits for geneticist appointments. Demand for advanced diagnostics is above the number of medical geneticists available in Puerto Rico, which triggers delayed diagnosis, management, and counseling. Therefore, these could affect the health disparities in our population with rare diseases. DISCUSSION/SIGNIFICANCE: This descriptive study will evaluate perceived stress in parents of pediatric patients living a diagnostic odyssey in Puerto Rico. No study has described perceived stress and access to care in this Hispanic population with undiagnosed conditions. Findings will contribute to a deep understanding of diagnostic process and limited access to care.
Tardive dyskinesia (TD) is a persistent and potentially disabling movement disorder associated with dopamine receptor blocking agents (eg, antipsychotics). Valbenazine is a highly selective vesicular monoamine transporter 2 inhibitor with several safe and effective dosing options now approved for once-daily (QD) treatment of TD in adults. Valbenazine 80 mg QD is the recommended dose for TD; however, 40 or 60 mg QD (newly approved dose) may be considered depending on response and tolerability. The recent approval of valbenazine 60 mg was based on results from an analysis that used the FDA’s model-informed drug development (MIDD) approach and leveraged existing data from the 6-week, phase 3 registration trial of valbenazine (KINECT 3).
Methods
A population pharmacokinetic (popPK) model was developed to describe plasma concentration-time profiles for valbenazine and its primary active metabolite, [+]-α-dihydrotetrabenazine ([+]-α-HTBZ). An exposure-response (E-R) model was developed using the area under the concentration-time curve (AUC) of [+]-α-HTBZ (exposure) and change from baseline in the Abnormal Involuntary Movement Scale total score (AIMS-CFB) (response). Stepwise E-R model development evaluated various linear and nonlinear models to describe AIMS-CFB vs [+]-α-HTBZ AUC and time. E-R relationships established with the 40 and 80 mg data were used to predict AIMS-CFB for a 60 mg dose up to week 6, accounting for study-to-study, inter-individual, and residual variabilities.
Results
Steady-state valbenazine and [+]-α-HTBZ concentrations were well described by a joint parent-metabolite popPK model. An Emax model with asymptotic exponential delay in the maximal valbenazine effect adequately characterized the E-R relationship between AIMS-CFB and [+]-α-HTBZ AUC. The simulated confidence intervals of response were consistent with the observed KINECT 3 results, demonstrating the utility of the model to predict efficacy results. The established E-R model was subsequently used to predict AIMS-CFB for valbenazine 60 mg QD at week 6. Mean AIMS scores decreased (improved) in a dose-dependent manner, with 60 mg QD predicted to result in least-squares mean (SEM) AIMS-CFB of −2.7 0.4, which is between the reported AIMS-CFB for 40 mg (−1.9 ± 0.4) and 80 mg (−3.2 ± 0.4). All simulated trials demonstrated valbenazine 60 mg to be significantly superior to placebo in AIMS-CFB after 6 weeks of treatment.
Conclusions
This analysis integrated and leveraged data from two previously approved valbenazine doses (40 and 80 mg QD) using an MIDD approach. The results provided key evidence that an intermediate dose (newly approved 60 mg QD) could be considered therapeutically beneficial without the need for an additional clinical trial. The availability of a valbenazine 60 mg dose to complement the previously approved doses fills an existing medical need for patients with TD who could benefit from this third effective dose.
OBJECTIVES/GOALS: Assess the diagnostic yield and test utilization of WES in patients having complex traits. We aim to evaluate the use of the first genetic approach for the identification of primary variants that contribute to neurogenetic disease etiology and influence onset and progression in Puerto Ricans. METHODS/STUDY POPULATION: Prospective cohort of 45 Puerto Rican probands (19 months - 36 years old) with complex neurogenetic traits that underwent WES (2019 - 2021). WES was performed, including copy number variant analysis and mitochondrial genome sequencing. We evaluated several factors possibly influencing the rate of WES diagnosis including early age, consanguinity, and family history of neurogenetic diseases. In addition, we only evaluated probands rather than dyads/trios and the clinical phenotypes. Descriptive analysis was performed, including a catalog of all variants reported. Multivariate analysis was performed to estimate the statistical association between variants and phenotypes reported and adjusting for potential confounders (age, sex, family history, income, health insurance and zip code). RESULTS/ANTICIPATED RESULTS: Auspiciously, positive pathogenic findings altered the clinical management in 29% of the probands in this study. A likely genetic diagnosis was achieved in 53% of the probands including pathogenic, likely pathogenic and variants of uncertain significance. Intronic variants, copy number variants detection and mitochondrial genome was included in WES methodology. Despite these facts, a 47% of the reported WES were negative, which deserve re-analysis potentially genotype based. Multivariate analysis is expected to adjust for potential confounders to establish a genotype-phenotype correlations in neurogenetic complex traits in this Puerto Rican admixed population. DISCUSSION/SIGNIFICANCE: Clinical WES offers an alternative approach for identification of variants in patients with complex traits. WES is also applicable in genetically heterogeneous individuals when specific genetic tests are not available or unsuccessful. Variants reported contribute to understand complex neurogenetic disease in underrepresented Puerto Ricans.
This chapter underscores the implicit messages about argument-based validity expressed in the volume. It highlights characteristics of validation illuminated by how the validation research was designed, carried out, interpreted, and presented by each researcher. The chapters show that argument-based validity applies not only to large-scale or high-stakes testing, but is relevant to a range of contexts where assessments are trusted and is called on at varying stages of test development. Argument-based validity has sufficiently detailed concepts for guiding research about technology-assisted testing methods, and it provides terms for defining different types of constructs. Argument-based validity frames research goals that are well-suited to mixed-methods designs, as illustrated in the chapters of this volume. The chapter ends by clarifying the limits of argument-based validation research by reviewing the facts about validation: Validity is not a yes-no decision about a test; validity is not an objective, deterministically derived result; and validity is not the sole responsibility of the experts. Argument-based validity does not change these facts, but rather provides a detailed and logical means of working within these parameters despite the desire of many test users for tests that have been validated by experts and can be adopted uncritically.
Argument-based validity has evolved in response to the needs of language testing researchers for a systematic approach to investigating validity of the language tests. Based on a collection of 51 recent books, articles, and research reports in language assessment, this chapter describes the fundamental characteristics of an argument-based approach to validity, which has been operationalized in various ways in language assessment. These characteristics demonstrate how argument-based validity operationalizes the ideals for validation presented by Messick (1989) and accepted by most language testers: that a validity argument should be unitary, but multifacted means for integrating a variety of evidence in an ongoing validation process. The chapter describes how validity arguments serve the multiple functions that language testers demand of their validation tools, and takes into account the concepts that are important in language testing. It distinguishes between two formulations of argument-based validity that appear in language testing to introduce the conventions used throughout the papers in the volume.
Validity Argument in Language Testing: Case Studies of Validation Research introduces argument-based validation and illustrates how the framework is used to conceptualize, design, implement, and interpret validation research for language tests and assessments. The first section introduces the principal concepts and key terms required to understand argument-based validity in language testing, and it identifies argument-based validation studies in language testing. The second section contains chapters reporting argument-based validity research to investigate score interpretation in six language assessments by conducting research on such issues as the reliability of scores, rating quality, the constructs assessed, and the abilities required in the domain of interest. The third part contains three chapters reporting studies of test score use, including their consequences. By presenting each of these studies with reference to a consistent, but customizable, framework for test interpretation and use, the chapters show the contribution of multiple types of investigations and the use of mixed methods research. The volume demonstrates the importance of argument-based validation of assessments for varying purposes and at different stages of test development, for technology-mediated language assessment, and for clarifying constructs definition. It also notes the limits of argument-based validity.