AMO Pharma Concludes FDA Meeting, Plans to Advance AMO-02 for Myotonic Dystrophy Treatment

AMO Pharma Limited, a privately held biopharmaceutical company specializing in rare genetic disorders, has announced plans to advance their investigational therapy AMO-02 (tideglusib) into a Phase 3 clinical trial. This decision follows a recent meeting with the U.S. Food and Drug Administration (FDA). The Phase 3 trial aims to evaluate the efficacy and safety of AMO-02 in adult patients with Type 1 myotonic dystrophy (DM1), a move toward future marketing authorization for treating DM1 across all age groups.

Earlier clinical trials, specifically the REACH-CDM Phase 2/3 study, focused on children and adolescents with congenital-onset DM1. The results indicated that AMO-02 was generally safe and well tolerated, with no severe adverse events directly attributed to the treatment. However, the study observed a significant placebo effect which may have obscured some therapeutic benefits. Despite this, post-hoc analysis supported the continued development of tideglusib, prompting the FDA to agree on proceeding to a Phase 3 study in adults with adult-onset DM1.

The FDA's review of the REACH-CDM Study data, focusing on safety and efficacy, influenced the design of the forthcoming Phase 3 trial. This new study will employ outcome measures similar to those demonstrating benefits in the REACH-CDM Study. The goal is to gather comprehensive safety and efficacy data to support a marketing application for DM1 treatment in children, adolescents, and adults.

AMO Pharma's executive chair, Alan Rubino, expressed satisfaction with the FDA discussions, emphasizing the potential of AMO-02 as a significant advancement in DM1 treatment. He acknowledged the support from various stakeholders and highlighted the company's focus on progressing the adult-onset DM1 clinical study. An announcement on the study's start date and locations is expected soon.

Hanns Lochmuller, an investigator in the REACH-CDM Study at the Children's Hospital of Eastern Ontario, expressed optimism about the therapy's potential impact. He highlighted the efficacy benefits observed in multiple symptom areas and the anticipation for the therapy's transformative effect on DM1 patients.

AMO-02, which targets DM1 through a dual mechanism involving pathogenic RNA repeat disruption and excess kinase GSK3β inhibition, was tested in a double-blind, placebo-controlled, randomized study involving 56 children and adolescents with congenital DM1 across sites in the U.S., Canada, New Zealand, and Australia. The study gathered functional and objective data, including motor and muscle assessments, cognitive performance, adaptive function, bone density, and creatine kinase levels. Post-hoc analyses indicated a higher positive response rate in participants treated with AMO-02 than with a placebo across most measures, showing significant improvements in walking, cognition, and biomarkers of muscle and neuronal integrity. Despite a primary analysis showing a placebo effect, treatment with AMO-02 resulted in clinically significant benefits.

AMO Pharma continues to support participants from this study and treatment-naïve patients in the REACH CDM-X open-label extension safety study. The company, dedicated to identifying and developing therapies for severe neurogenetic disorders, is also working on AMO-01 for Phelan-McDermid syndrome and AMO-04 for Rett syndrome and related conditions. These investigational therapies have not yet received approval for patient treatment globally.

The company remains committed to progressing its clinical development programs and working closely with the FDA and the broader scientific community to ensure the swift advancement of promising therapies for unmet medical needs in rare disorders.