Publicaciones científicas

L-serine treatment in patients with GRIN-related encephalopathy: A phase 2A, non-randomized study

21-feb-2024 | Revista: Brain

Natalia Juliá-Palacios  1 , Mireia Olivella  2   3 , Mariya Sigatullina Bondarenko  1 , Salvador Ibáñez-Micó  4 , Beatriz Muñoz-Cabello  5 , Olga Alonso-Luengo  5 , Víctor Soto-Insuga  6 , Deyanira García-Navas  7 , Laura Cuesta-Herraiz  8 , Patricia Andreo-Lillo  9 , Sergio Aguilera-Albesa  10 , Antonio Hedrera-Fernández  11 , Elena González Alguacil  6 , Rocío Sánchez-Carpintero  12 , Fernando Martín Del Valle  13 , Erika Jiménez González  14 , Lourdes Cean Cabrera  4 , Ines Medina-Rivera  1 , Marta Perez-Ordoñez  15 , Roser Colomé  1 , Laura Lopez  16 , María Engracia Cazorla  16 , Montserrat Fornaguera  16 , Aida Ormazabal  17 , Itziar Alonso-Colmenero  18 , Katia Sofía Illescas  1 , Sol Balsells-Mejía  19 , Rosanna Mari-Vico  1 , Maria Duffo Viñas  1   15 , Gerarda Cappuccio  20   21 , Gaetano Terrone  20 , Roberta Romano  20 , Filippo Manti  22 , Mario Mastrangelo  23   24 , Chiara Alfonsi  22 , Bruna de Siqueira Barros  25 , Mathilde Nizon  26 , Cathrine Elisabeth Gjerulfsen  27 , Valeria L Muro  28 , Daniela Karall  29 , Fiona Zeiner  29 , Silvia Masnada  30 , Irene Peterlongo  30 , Alfonso Oyarzábal  1 , Ana Santos-Gómez  31   32 , Xavier Altafaj  31   32 , Ángeles García-Cazorla  1


Abstract

GRIN-related disorders are rare developmental encephalopathies with variable manifestations and limited therapeutic options. Here, we present the first non-randomized, open-label, single-arm trial (NCT04646447) designed to evaluate tolerability and efficacy of L-serine in children with GRIN genetic variants leading to loss-of-function.

In this phase 2A trial, patients aged 2-18 years with GRIN loss-of-function pathogenic variants received L-serine for 52-weeks. Primary endpoints included safety and efficacy by measuring changes in the Vineland Adaptive Behavior Scales, Bayley Scales, age-appropriate Wechsler Scales, Gross Motor Function-88, Sleep Disturbance Scale for Children, Pediatric Quality of Life, Child Behavior Checklist and the Caregiver-Teacher Report Form following 12 months treatment.

Secondary outcomes included seizure frequency and intensity reduction and electroencephalography improvement. Assessments were performed 3 months and 1 day before starting treatment and 1-3-6-12 months after the beginning of the supplement. Twenty-four participants were enrolled (13 males/11 females, mean age 9.8 years, SD 4.8), 23 of whom completed the study. Patients had GRIN2B, GRIN1 and GRIN2A variants (12, 6 and 5 cases, respectively).

Clinical phenotype showed: 91% intellectual disability (61% severe), 83% behavioral problems, 78% movement disorders and 58% with epilepsy. Based on Vineland Adaptive Behavior Composite standard score, nine children were classified as mildly impaired level group (cut-off > 55), whereas 14 were assigned to the clinically severe group. An improvement was detected in Daily Living Skills domain (P = 0,035) from the Vineland Scales within the mild group. Expressive (P = 0.005), Personal (P = 0.003), Community (P = 0.009), Interpersonal (P = 0.005) and Fine Motor (P = 0.031) subdomains improved for the whole cohort, although improvement was mostly found in the mild group.

Growth Score Values cognitive subdomain on the Bayley-III showed a significant improvement in the severe group (P = 0.016), with a mean increase of 21.6 points. L-serine treatment was associated with significant improvement in the median Gross Motor Function-88 total score (P = 0.002) and the mean Pediatric Quality of Life total score (P = 0.00068) regardless of severity. L-serine normalized EEG pattern in five children, and the frequency of seizures in one clinically affected child. One patient discontinued treatment due to irritability and insomnia.

The trial provides evidence that L-serine is a safe treatment for children with GRIN loss-of-function variants, having the potential to improve the adaptive, motor function and quality of life, with a better response to the treatment in mild phenotypes.

CITA DEL ARTÍCULO  Brain. 2024 Feb 21:awae041.  doi: 10.1093/brain/awae041

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