Decreased phenylalanine, phenylalanine/tyrosine ratio and increased tyrosine pku treatment dose mitigation observed compared to baseline levels

Homology, a gene drug company, recently released preliminary clinical data from its first clinical trial of gene therapy for phenylketonuria (PKU). The PHENIX trial is a Phase 1/2 randomized, concurrent controlled, dose escalation study in adults with PKU.

Two patients in cohort 1 (low dose) and one patient in cohort 2 (medium dose) received investigational hmi-102 gene therapy. preliminary safety data from cohorts 1 and 2 indicate that hmi-102 is acceptable.

Efficacy data for the first patient in Cohort 2 showed a range of dose mitigation results observed with reduced phenylalanine (Phe) levels, increased tyrosine (Tyr) and a reduced Pheu002FTyr ratio compared to baseline, suggesting increased enzyme activity.

Phenylalanine is the primary endpoint of PKU, and tyrosine is a product of phenylalanine metabolism and a precursor of neurotransmitters. The phenylalanineu002F tyrosine ratio is a clinically relevant diagnostic indicator of PKU.

"We can be confident that the preliminary efficacy studies conducted through Cohort 2 demonstrate that HMI-102 can deliver the PAH gene, produce a functional phenylalanine hydroxylase (PAH) enzyme, and restore the biochemical pathway for the conversion of phenylalanine to a tyrosine.

The observed safety results and trial design allowed us to rapidly implement a dose increase program with a wide enough safety profile to provide the potential for further dose increases."