Safety and Tolerability of RTX-134 in Adults With Phenylketonuria

• Register: ClinicalTrials.gov
• Last refreshed on: 9 January 2023
• Main ID: NCT04110496
• Date of registration: 23/09/2019
• Prospective Registration: Yes
• Primary sponsor: Rubius Therapeutics
• Public title: Safety and Tolerability of RTX-134 in Adults With Phenylketonuria
• Scientific title: A Phase 1b Open-Label Single Dose Safety, Tolerability, and Pharmacokinetics Study of RTX-134 in Adults With Phenylketonuria
• Date of first enrolment: January 29, 2020
• Target sample size: 1
• Recruitment status: Terminated
• URL: https://clinicaltrials.gov/show/NCT04110496
• Study type: Interventional
• Study design: Allocation: N/A. Intervention model: Single Group Assignment. Primary purpose: Treatment. Masking: None (Open Label).
• Phase: Phase 1

Countries of recruitment

United States

Key inclusion & exclusion criteria

Inclusion Criteria

1. Age 18 years or older with:

1. A clinical diagnosis of PKU, and

2. Average blood phenylalanine level = 600 µmol/L based on 2 assessments up to 3
weeks apart during the 6-month period before Day 0 (per available data)

2. Stable diet, including medical formula

3. Must be a man or a woman not of childbearing potential and agree to use adequate
contraception throughout and for one year following study participation.

4. Adequate organ function

5. Negative antibody detection on type and screen and no evidence of clinical hemolysis

Exclusion Criteria

1. Known hypersensitivity to any component of study treatment

2. Prior treatment with Pegaliase

3. Start of sapropterin dihydrochloride within 3 weeks of study dosing

4. Use of an investigational agent within 28 days of study dosing

5. Concurrent participation in an interventional trial involving ongoing treatment,
including placebo.

6. Infections requiring antimicrobial treatment within 7 days of study dosing

7. Chronic infections, such as HIV, hepatitis B, or untreated hepatitis C

8. Conditions that may alter survival of red blood cells, (e.g., autoimmune diseases,
splenectomy, etc)

9. Pregnant or breastfeeding



Age minimum: 18 Years
Age maximum: N/A
Gender: All

Health Condition(s) or Problem(s) studied

Phenylketonurias

Intervention(s)

Drug: RTX-134

Primary Outcome(s)

To correlate dose with percent reduction in serum phenylalanine levels relative to baseline [Time Frame: Baseline to 28 days after last detection of RTX-134]

To evaluate the safety and tolerability of RTX-134 as measured by frequency of treatment emergent adverse events [Time Frame: Baseline to 28 days after last detection of RTX-134]

To determine a preliminary dose to achieve serum phenylalanine levels < 360 µmol/L [Time Frame: Baseline to 28 days after last detection of RTX-134]

To determine a preliminary dose to achieve serum phenylalanine levels < 600 µmol/L [Time Frame: Baseline to 28 days after last detection of RTX-134]

To evaluate the pharmacokinetics of RTX-134 as measured by presence of AvPal expressing red cells, AvPAL protein in red cells and serum, and AvPAL enzymatic activity. [Time Frame: Baseline to 28 days after last detection of RTX-134]

Secondary ID(s)

RTX-134-01

Source(s) of Monetary Support

Please refer to primary and secondary sponsors