RIBOMIC, Inc. has announced positive interim results from its Phase IIa clinical trial of umedaptanib pegol (anti-FGF2 aptamer) in pediatric patients aged 5-14 years with achondroplasia (ACH). The trial's low-dose cohort (0.3 mg/kg subcutaneous injection once a week) demonstrated a significant impact on patient growth rate, offering a potential new treatment avenue for this rare condition.
In the low-dose cohort, comprising six subjects, five of whom completed the study without medication interruption, two patients exhibited notable increases in height growth rate. Specifically, these patients showed increases of +4.6 cm/year and +3.3 cm/year compared to their pre-treatment baseline, as determined by an observational study. These findings suggest a substantial therapeutic effect, especially when compared to the +1.7 cm/year average height growth rate reported for Voxzogo (vosoritide), a currently approved treatment for ACH manufactured by BioMarin.
Continued Evaluation and Future Studies
Five of the initial subjects have transitioned to a long-term, low-dose administration study to further assess the efficacy and safety of umedaptanib pegol. Concurrently, enrollment has been completed for a high-dose cohort (0.6 mg/kg subcutaneous administration once every two weeks), with treatment initiated in four patients. Results from the high-dose cohort study are anticipated in September 2025.
Safety Profile
The ongoing Phase IIa clinical trials have not raised any safety concerns to date.
Umedaptanib Pegol: A Novel Approach
Umedaptanib pegol, previously known as RBM-007, is an aptamer-based therapeutic designed to inhibit fibroblast growth factor 2 (FGF2). It is posited to directly address the underlying pathogenic mechanism of achondroplasia. The drug has previously demonstrated clinical proof-of-concept in exudative age-related macular degeneration.
Achondroplasia: An Unmet Need
Achondroplasia arises from a genetic mutation in fibroblast growth factor receptor 3 (FGFR3), leading to excessive activation of FGFR3. This, in turn, inhibits normal cartilage and tissue growth, resulting in short stature and other characteristic symptoms. Affecting approximately 1 in 25,000 newborns, achondroplasia is considered a rare and intractable condition, highlighting the need for effective therapeutic interventions.
