PKU Treatment with HMI-102 Gene Therapy: The pheNIX Study – Phase I/II

Dose Escalation Study to Evaluate the Safety and Efficacy of HMI-102 in Adult PKU Subjects with PAH Deficiency

Protocol Description

This multi-center study determines the effects, including safety and tolerability, of a single-dose of the investigational drug HMI-102 in people with classic phenylketonuria (PKU) caused by a deficiency in the gene responsible for making an enzyme called phenylalanine hydroxylase (PAH). The study aims to provide participants with a working version of the PAH gene delivered by HMI-102, a gene transfer vector.

Study Level: Phase I/II

Eligibility Criteria

Subject to certain exclusion criteria, this study is enrolling participants ages 18 to 55 who have classic PKU due to PAH deficiency.
Males and Females: Ages 18 to 55


To determine the highest dose of HMI-102 that people can take without having unacceptable side effects, the study will test increasingly higher doses of HMI-102 in different groups of participants, as determined by random selection. The start time of some participants will be deferred by 6 months. Following initial screening, participants will receive a single dose of HMI-102 via intravenous infusion in the hospital setting with examinations on the subsequent 2 days. Participants will then be followed with weekly visits for the next 20 weeks, in which  examinations, blood testing and other tests and procedures will be conducted. Participants will have another dozen visits during the remaining 30 weeks of the study. Participants will have the option of being in a long-term extension study for an additional 4 years.
Visits: 36 over the course of 1 year
Duration: 1 year or 1.5 years, if start date is deferred

Status: Open to Enrollment

Source(s) of Support

Homology Medicines

Primary Investigator

Gerard Vockley, MD, PhD

Contact Information

For more information about the study or enrollment, please contact: 
Jessica Lindenberger, MSN, CRNP, FNP-C