Marvel Biosciences' experimental treatment MB204 has shown promising results in improving social behaviors in a mouse model of Rett syndrome. The preclinical study, conducted in collaboration with the International Institute for the Brain (iBRAIN), compared MB204 to Trofinetide (Daybue), the only FDA-approved treatment for Rett syndrome. The findings indicate that MB204 has a more durable effect on social behaviors, lasting 21 days post-treatment, compared to Trofinetide's 14-day effect.
MB204 Demonstrates Superior Durability
Rett syndrome, primarily caused by mutations in the MECP2 gene, leads to cognitive, sensory, emotional, and motor issues, typically emerging between 6 and 18 months of age. MB204, a derivative of istradefylline, works by blocking adenosine A2a receptors, a mechanism suggested as a potential therapeutic target in Rett syndrome.
The study involved treating mice with either MB204 or Trofinetide for two weeks, with subsequent weekly analyses. According to Marvel, MB204's sustained improvements in social behaviors suggest a durable post-treatment and potential neuromodulation effect. In contrast, the effects of Trofinetide were minimal after 14 days.
Comparison with Trofinetide
Trofinetide, marketed as Daybue by Acadia Pharmaceuticals, was approved by the FDA in 2023 as the first treatment for Rett syndrome. In clinical trials, Daybue improved scores on assessments related to fear, anxiety, body rocking, and facial expressions. Marvel Biosciences is positioning MB204 as a potentially faster, more effective treatment at lower doses than existing options.
In the preclinical study, MB204 was administered orally at 10 mg/kg once daily, while Trofinetide was given via intraperitoneal injection at 100 mg/kg once daily. Preliminary data indicated that MB204 outperformed Trofinetide in most studied endpoints, showing a near reversal of direct social and behavioral deficits after two weeks of treatment.
Next Steps for MB204
Marvel Biosciences intends to seek orphan and/or rare disease designation from the FDA for MB204 in Rett syndrome. This designation could provide benefits such as market exclusivity and tax incentives. Full preclinical study results are expected in the first quarter of 2025, with Phase 1 clinical trials anticipated to start later in the year.
"MB204 continues to exceed our expectations in pre-clinical studies," said Dr. Mark Williams, Marvel’s chief science officer. "MB204’s long-last effects are particularly exciting and encouraging."
Marvel is also investigating MB204 for other conditions, including fragile X syndrome and Alzheimer’s disease. Rod Matheson, Marvel’s CEO, noted that any FDA designations would be helpful in these additional programs.
