Objective Infantile-onset spinal muscular atrophy (SMA) is the most common genetic cause of infant mortality, typically resulting in death prior to age 2. Clinical trials in this population require an understanding of disease progression and identification of meaningful biomarkers to hasten therapeutic development and predict outcomes. Methods A longitudinal, multi-center, prospective natural history study enrolled 26 SMA infants, and 27 control infants less than six months of age. Recruitment occurred at 14 centers over 21 months within the NINDS-sponsored NeuroNEXT Network. Infant motor function scales (TIMPSI, CHOP-INTEND and AIMS) and putative physiologic and molecular biomarkers were assessed prior to 6 months of age and at 6, 9, 12, 18 and 24-months with progression, correlations between motor function and biomarkers and hazard ratios were analyzed. Results Motor function scores (MFS) and CMAP decreased rapidly in SMA infants, whereas MFS in all healthy infants rapidly increased. Correlations were identified between TIMPSI and CMAP in SMA infants. TIMPSI at first study visit was associated with risk of combined endpoint of death or permanent invasive ventilation in SMA infants. Post hoc analysis of survival to combined endpoint in SMA infants with 2 copies of SMN2 indicated a median age of 8 months at death (95%CI: 6,17). Interpretation These data of SMA and control outcome measures delineates meaningful change in clinical trials in infantile-onset SMA. The power and utility of NeuroNEXT to provide “real world”, prospective natural history data sets to accelerate public and private drug development programs for rare disease is demonstrated.

ObjectiveThis study prospectively assessed putative promising biomarkers for use in assessing infants with spinal muscular atrophy (SMA).MethodsThis prospective, multi‐center natural history study targeted the enrollment of SMA infants and healthy control infants less than 6 months of age. Recruitment occurred at 14 centers within the NINDS National Network for Excellence in Neuroscience Clinical Trials (NeuroNEXT) Network. Infant motor function scales and putative electrophysiological, protein and molecular biomarkers were assessed at baseline and subsequent visits.ResultsEnrollment began November, 2012 and ended September, 2014 with 26 SMA infants and 27 healthy infants enrolled. Baseline demographic characteristics of the SMA and control infant cohorts aligned well. Motor function as assessed by the Test for Infant Motor Performance Items (TIMPSI) and the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP‐INTEND) revealed significant differences between the SMA and control infants at baseline. Ulnar compound muscle action potential amplitude (CMAP) in SMA infants (1.4 ± 2.2 mV) was significantly reduced compared to controls (5.5 ± 2.0 mV). Electrical impedance myography (EIM) high‐frequency reactance slope (Ohms/MHz) was significantly higher in SMA infants than controls SMA infants had lower survival motor neuron (SMN) mRNA levels in blood than controls, and several serum protein analytes were altered between cohorts.InterpretationBy the time infants were recruited and presented for the baseline visit, SMA infants had reduced motor function compared to controls. Ulnar CMAP, EIM, blood SMN mRNA levels, and serum protein analytes were able to distinguish between cohorts at the enrollment visit.

Background Vincristine-induced peripheral neuropathy (VIPN) is difficult to quantify in children. Objective The study objective was to examine the reliability, validity, and clinical feasibility of several VIPN measures for use in children with acute lymphoblastic leukemia. Interventions/Methods Children (N = 65) aged 1–18 years receiving vincristine at four academic centers participated in the study. Baseline and pre-vincristine VIPN assessments were obtained using the Total Neuropathy Score-Pediatric Vincristine (TNS-PV), the National Cancer Institute Common Terminology Criteria for Adverse Events, the Balis grading scale, and the FACES pain scale. TNS-PV scores (n = 806) were obtained over 15 weeks. Blood was obtained at several time-points to quantify pharmacokinetic parameters. Results Cronbach’s alpha for a reduced TNS-PV scale was 0.84. TNS-PV scores correlated with cumulative vincristine dosage (r = 0.53, p = 0.01), pharmacokinetic parameters (r = 0.41, p = 0.05), and grading scale scores (r = 0.46 – 0.52; p = 0.01). FACES scores correlated with the TNS-PV neuropathic pain item (r = 0.48; p = 0.01), and were attainable in all ages. A 2-item V-Rex score (vibration and reflex items) was the most responsive to change (es 0.65, p < 0.001). TNS-PV scores were attainable in 95% of children ≥ 6 years. Conclusions The TNS-PV is reliable and valid for measuring VIPN. It is sensitive to change over time (15 weeks) and feasible for use in children ≥ 6 years of age. Implications for Practice The TNS-PV may be a useful tool for assessing vincristine toxicity in children with acute lymphoblastic leukemia.