Longitudinal Adaptive Functioning Outcomes in Children with Autism Spectrum Disorder During a 180 Day Open-Label Extension of K11-Tmax, a Consortium Probiotic Mix with Multivitamins

Autism spectrum disorder (ASD) is frequently associated with gastrointestinal symptoms, immune dysregulation, and altered microbiota-related signaling, supporting interest in microbiota-targeted interventions. This study evaluated adaptive functioning for over 180 days in children with ASD in a previously randomized controlled trial (RCT). After the initial 90-day blinded phase, the study continued as an open-label extension (OLE) in which all participants received K11 TMAX, a kefir-derived probiotic consortium combined with a microencapsulated micronutrient blend. The study included 130 children (3–11 years of age) who continued from the RCT were followed-up in three different trajectories: (1) placebo → K11-TMAX; (2) K11 → K11-TMAX; and (3) continued K11-TMAX supplementation. Children’s adaptive functioning was assessed by the Vineland Adaptive Behavior Scales, Third Edition (Vineland-3), Adaptive Behavior Composite (ABC) as well as by four core domains: (1) communication; (2) daily living skills; (3) socialization; and (4) motor skills. All three groups of children improved significantly on all of the parameters that were assessed with the effect sizes ranging from 0.13 to 0.43. The greatest improvement in the communication domain was seen in the transition group (1) and the greatest decrease in the externalizing behavior scores were seen in the continuous group (3) of children. Children’s adaptive functioning improved in clinically meaningful ways. Children’s improvement, however, was within the disability range and did not reach the level of typical development of children of the same age. These findings suggest supplementary therapeutic use of K11-TMAX, modulating the gut–brain axis, in children with autism spectrum disorder (ASD).