PaxMedica announced positive results from a phase 2 dose-ranging clinical trial evaluating PAX-124890-=101 demonstrated sustained improvements over placebo in the trial’s primary and several secondary endpoints and a favorable safety and tolerability profile. PaxMedica expects to submit a full analysis of the Phase 2 data for presentation at an upcoming medical conference and publication in a peer-reviewed scientific journal.
The phase 2 dose-ranging, randomized, double-blind, placebo-controlled trial enrolled 52 patients diagnosed with moderate to severe autism spectrum disorder across 6 sites in South Africa. In the 14-week trial, patients were randomized 1:1:1 to receive 10mg/kg of PAX101, 20mg/kg of PAX-101 or placebo infusions every 4 weeks. Infusions were administered at baseline, week 4 and week 8. There was a 6-week follow-up after the last dose of study medication. The primary endpoint of the study was the change between baseline and Week 14 in the Aberrant Behavior Checklist (ABC) composite score of core symptoms (ABC Core) including ABC-II (lethargy/social withdrawal), ABC-III (stereotypy) and ABC-V (inappropriate speech).
At Week 14, there was a mean 48% improvement from baseline in the ABC Core in patients on active treatment versus 31% on placebo, with twice as many actively treated patients exhibiting a 70% or greater improvement versus placebo. At Week 14, patients treated with PAX-101 also demonstrated a mean improvement from baseline in the Clinical Global Impression of Improvement scale, adapted for autism (CGI-I) overall symptom severity score of 0.9 points versus 0.4 on placebo, representing a clinically meaningful change from baseline. Certain key subpopulations demonstrated even further improvements on these and other assessments.
The most common treatment-emergent adverse events in drug treated patients were rash, upper respiratory infection and vomiting. Most events were mild to moderate in severity and resolved with no intervention.
About PAX-101 (IV suramin)
PAX-101, an antipurinergic agent delivered as an IV infusion, has been shown to have significant anti-inflammatory properties based on non-purine receptor pathways in multiple disease models. The mechanism of the drug’s action in a condition like ASD is not fully understood and has been postulated to act through purinergic receptor blockade to reverse the effects of mitochondrial dysfunction, but also has been postulated to act through the reduction of neuroinflammation in this population.
About Autism Spectrum Disorder (ASD)
ASD refers to a group of complex neurodevelopmental disorders characterized by repetitive and characteristic patterns of behavior and difficulties with social communication and interaction. These symptoms are present from early childhood and affect daily functioning of individuals with ASD. The term “spectrum” refers to the wide range of symptoms, skills, and levels of disability in functioning that can occur in people with ASD. ASD occurs in every racial and ethnic group, and across all socioeconomic levels. Approximately 1 in 54 children in the U.S. is diagnosed with an autism spectrum disorder with boys being four times more likely to be diagnosed than girls. There are presently no FDA approved therapies for the core symptoms of autism.