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Safety and Tolerability of RTX-134 in Adults With Phenylketonuria

A Phase 1b Open-Label Single Dose Safety, Tolerability, and Pharmacokinetics Study of RTX-134 in Adults With Phenylketonuria

Status
Terminated
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT04110496
Enrollment
1
Registered
2019-10-01
Start date
2020-01-29
Completion date
2022-12-01
Last updated
2022-12-08

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Phenylketonurias

Brief summary

This study will evaluate the safety and tolerability of RTX-134 in adult patients with PKU.

Detailed description

This is a Phase 1b first-in-human trial in adult subjects with PKU. The primary objective of this study is to evaluate the safety and tolerability of RTX-134 following intravenous administration of a single dose. RTX-134 consists of allogeneic human red cells expressing the AvPAL (Anabaena variabilis phenylalanine ammonia lyase) gene inside the cell. The trial is designed to determine a preliminary dose and inform a dosing schedule that is deemed safe, tolerable, and potentially effective. Four dose levels are planned, additional dose levels may be explored. Following administration, subjects will be monitored until 28 days after last detection of RTX-134. Detection of RTX-134 will be evaluated using multiple pharmacokinetic (PK) and pharmacodynamic (PD) assessments including measurement of trans-cinnamic acid (tCA).

Interventions

DRUGRTX-134

RTX-134 is a cellular therapy containing AvPAL

Sponsors

Rubius Therapeutics
Lead SponsorINDUSTRY

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Intervention model description

Single Ascending Dose

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

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

Design outcomes

Primary

MeasureTime frame
To evaluate the safety and tolerability of RTX-134 as measured by frequency of treatment emergent adverse eventsBaseline to 28 days after last detection of RTX-134
To correlate dose with percent reduction in serum phenylalanine levels relative to baselineBaseline to 28 days after last detection of RTX-134
To determine a preliminary dose to achieve serum phenylalanine levels < 600 µmol/LBaseline to 28 days after last detection of RTX-134
To determine a preliminary dose to achieve serum phenylalanine levels < 360 µmol/LBaseline 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.Baseline to 28 days after last detection of RTX-134

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026