Pathogenic variants in the Cyclin-dependent kinase like 5 (CDKL5) gene cause CDKL5 deficiency disorder (CDD, MIM 300672, 105830) a severe developmental and epileptic encephalopathy (DEE) associated with cognitive and motor dysfunction and cortical visual impairment. Recent data suggest CDD is one of the most common genetic causes of DEE. Work in CDD animal models has demonstrated the ability for disease modification and symptom reversal: worldwide efforts are now underway to develop therapeutic strategies (including gene therapy) to treat and potentially cure CDD. While there are four active clinical trials, none assesses the full spectrum of this DEE to address true disease modification. While capability for disease modifying therapies is accelerating, there is a critical barrier for clinical trial readiness that may result in failure of these therapies, not due to lack of efficacy but due to lack of validated outcome measures. CDD has been associated historically with Rett syndrome but there are many clear distinctions and CDD has emerged as an independent disorder. Some Clinical Outcome Measures (COMs) can be adapted from Rett syndrome COMs, whereas others need to be developed specifically for CDD. Our research network is uniquely positioned to develop clinical trial readiness for CDD by pairing exceptional experience in the development and validation of outcome measures with an extensive network of CDD experts and clinical trialists. Our goals are to 1) refine and validate appropriate quantitative COMs and biomarkers and 2) conduct a multi-site clinical trial readiness study to ensure that they can be successfully implemented. We will test the hypothesis that CDD specific COMs can be refined to accurately and reproducibly track meaningful changes in clinical trials: Aim 1: Generate and validate a suite of COMs and biomarkers necessary to comprehensively assess disease modification in CDD. Aim 2: Conduct a multi-site clinical trial readiness study to assess implementation, longitudinal stability, and collect baseline COMs and EEG/evoked potential data. Overall Impact: These outcome measures will establish clinical trial readiness for CDD and generate historic baseline outcome data, ensuring optimal testing of potential new therapeutics including gene therapy. Furthermore, these measures will be adaptable to other DEEs by enabling choices of outcome measures beyond existing NINDS supported measurement tools (NeuroQoL, PROMIS, Toolbox) that are not designed for the severity of the DEE populations.

Project Narrative: Pathogenic variants in the Cyclin-dependent kinase like 5 (CDKL5) gene cause CDKL5 deficiency disorder (CDD, MIM 300672, 105830), a severe developmental and epileptic encephalopathy associated with cognitive and motor impairments and cortical visual impairment. While capability for disease modifying therapies is accelerating, there is a critical barrier for clinical trial readiness that may result in failure of these therapies, not due to lack of efficacy but due to lack of validated outcome measures and biomarkers. The measures and biomarkers validated here will be adaptable to other developmental and epileptic encephalopathies.