Mezzion Pharma Co. Ltd. met with the FDA Division of Cardiology and Nephrology May 27th to discuss with the FDA the path forward for the regulatory approval of udenafil for the treatment of single ventricle heart disease in children with Fontan physiology. More specifically, Mezzion sought clarity on the critical elements of an additional clinical trial that may be needed to complete the NDA submission.

The FDA responded to the Meeting Background Package that was submitted by Mezzion to DCN with detailed advice and direction for the path forward for an FDA approval. Specifically, only one new clinical trial, FUEL-2, will be needed. FUEL-2 will be similar to the previously completed FUEL-1 trial in the adolescent and young adult population.

The primary difference in FUEL-2 will be the exclusion of 'Super Fontan' patients with peak VO2 = 80% of predicted to avoid de-enriching the FUEL-2 study population. Therefore learned from FUEL-1 that, when the 'Super Fontan' patients were excluded from the FUEL-1 study population, the subgroup met both the primary and secondary endpoints. Therefore confident that will achieve similar statistical significance for the primary and secondary endpoints in FUEL-2 with an enriched target population.

If the additional new trial meets statistical significance on the primary endpoint, then FDA agreed that it will be considered a positive trial and sufficient for approval. The FDA also advised that meeting statistical significance on the secondary endpoints, while enhancing the potential labeling for the product, would not be a prerequisite for approval. Mezzion anticipates enrolling the first patient within the next few months.

The FDA agreed with Mezzion regarding the specific primary and secondary endpoints to use for the measurement of function capacity in trial subjects in the new trial, FUEL-2, and further agreed that the protocol for this new trial would be reviewed by DCN under a Special Protocol Assessment.