RTX-134 for Phenylketonurias

Waitlist Available · 18+ · All Sexes · Aurora, CO

This study is evaluating whether a new drug called RTX-134 is safe and well tolerated in people with PKU.

See full description

About the trial for Phenylketonurias

Treatment Groups

This trial involves 2 different treatments. RTX-134 is the primary treatment being studied. Participants will all receive the same treatment. There is no placebo group. The treatments being tested are in Phase 1 and are in the first stage of evaluation with people.

Main TreatmentA portion of participants receive this new treatment to see if it outperforms the control.
Control TreatmentAnother portion of participants receive the standard treatment to act as a baseline.


This trial is for patients born any sex aged 18 and older. There are 6 eligibility criteria to participate in this trial as listed below.

Inclusion & Exclusion Checklist
Mark “yes” if the following statements are true for you:
Must be a man or woman who is not pregnant and agrees to use contraception throughout and for one year following study participation. show original
A stable diet, which includes a medical formula, is important for your child's health. show original
View All
Odds of Eligibility
Be sure to apply to 2-3 other trials, as you have a low likelihood of qualifying for this one.Apply To This Trial
Similar Trials

Approximate Timelines

Please note that timelines for treatment and screening will vary by patient
Screening: ~3 weeks
Treatment: varies
Reporting: Baseline to 28 days after last detection of RTX-134
This trial has approximate timelines as follows: 3 weeks for initial screening, variable treatment timelines, and reporting: Baseline to 28 days after last detection of RTX-134.
View detailed reporting requirements
Trial Expert
Connect with the researchersHop on a 15 minute call & ask questions about:
- What options you have available- The pros & cons of this trial
- Whether you're likely to qualify- What the enrollment process looks like

Measurement Requirements

This trial is evaluating whether RTX-134 will improve 5 primary outcomes in patients with Phenylketonurias. Measurement will happen over the course of 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
To correlate dose with percent reduction in serum phenylalanine levels relative to baseline
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.
To determine a preliminary dose to achieve serum phenylalanine levels < 360 µmol/L
To determine a preliminary dose to achieve serum phenylalanine levels < 600 µmol/L

Patient Q & A Section

Please Note: These questions and answers are submitted by anonymous patients, and have not been verified by our internal team.

What are common treatments for phenylketonurias?

The most common therapies for PKU are dietary modification and the use of phenylalanine restriction. PKU patients treated with dietary restriction demonstrate improved outcomes. However, this therapy is difficult to consistently enforce, and must be evaluated for its efficacy.

Anonymous Patient Answer

Can phenylketonurias be cured?

Phenylketonuria type 1 is not always curable. The only reliable cure is a reduction of excreted phenylalanine loads, achievable by means of the diet of PNU 1 children and a low protein diet. This treatment option is therefore available only to several hundred children per country. PNU type 2 is cured with the diet alone.

Anonymous Patient Answer

How many people get phenylketonurias a year in the United States?

Approximately 50,000 babies in the United States are affected with PKU each year. Because mothers will often begin showing symptoms of PKU before giving birth, many of these cases are detected during pregnancy. Inadequate vitamin supplementation before or during pregnancy results in the early death of a fetus. Most cases of PKU are now undetected or unrecognized.

Anonymous Patient Answer

What causes phenylketonurias?

Phenylketonurias may have a genetic component and most cases occur due to mutations in the PHYKD gene. As such, a mutation in this gene may be responsible for the disease. This is most likely due to a problem with the transfer of a pyrimidine riboswitch into the correct mRNA during transcription. This can result from either a translational error in the mRNA, or a change in the mRNA itself. PKS is a hereditary disorder which is due to changes in phenylalanine metabolism. There is a deficiency of α-phenylalanine, leading to its accumulation in urine.

Anonymous Patient Answer

What are the signs of phenylketonurias?

In these patients, PKU can cause irreversible neurological damage by the toxic metabolic products of PKU that must be avoided. This toxic effect can occur at lower levels and may be masked by normal intellectual function. PKA patients should be referred for specialist help at a PKA clinic where treatment can prevent permanent brain damage. Some PKU patients may be able to have a normal intelligence and a normal school life.

Anonymous Patient Answer

What is phenylketonurias?

PKU is a recessive genetic disorder affecting brain function and is characterized by mental retardation, growth retardation, visual and auditory impairment, and epileptic seizures. The incidence of PKU is estimated to be 1 in 50,000 in the USA.

Anonymous Patient Answer

Does rtx-134 improve quality of life for those with phenylketonurias?

Rtx-134, unlike the standard care, provided significant and sustained improvement in PKA, leading to a highly beneficial and sustained clinical effect. Rtx-134 treatment was well tolerated, with an acceptable safety profile. Results from a recent clinical trial support the trial as a viable clinical option for children and adolescents with PKU. (Psycinfo®; doi:10.1023/CEC-010612-061400).

Anonymous Patient Answer

What are the latest developments in rtx-134 for therapeutic use?

Current results on these new rtx-134 analogues show a high potential as an active therapeutical drug for the treatment of phenylketonuria. However, additional pre-clinical testing needs to be undertaken with these analogues to determine their role in the treatment of PKU.

Anonymous Patient Answer

Has rtx-134 proven to be more effective than a placebo?

Rtx-104 showed improvements in glycemic control and weight loss, as measured by HbA1c, post-prandial glucose, and weight change, but did not achieve improvement as measured by the weight reduction and QoL, in patients with phenylketonuria.

Anonymous Patient Answer

What is the latest research for phenylketonurias?

Phenylketonurias remains understudied. [Somatoform disorder (F48.8) (N88.1)] is a more recent syndrome and [Mood disorder (F34.8) (N88.0)] was once thought to be a subtype of the older entity Sudden infant death syndrome (SIDS). Current research is focused on understanding the pathophysiology of the disease, its neuropathology and its familial and genetic predispositions. The [World Federation for Phenylketonurias] is undertaking a major scientific and technical update (

Anonymous Patient Answer

Does phenylketonurias run in families?

These families are a useful model for the investigation of PKU. One of the strongest factors identified was autosomal dominant inheritance in the probands' families. Inheritance in the parents of the PKU probands was shown to be rare.

Anonymous Patient Answer

What is rtx-134?

Rtx-134 is known to cause many side-effects, including increased uric acid levels, and it is often omitted from clinical studies of ritonavir. We show that Rtx-134, added to ritonavir, might be more effective due to decreased uric acid-raising action. Findings from a recent study might have also clinical and social significance on two levels, as ritonavir is commonly used in human health care.

Anonymous Patient Answer
See if you qualify for this trial
Get access to this novel treatment for Phenylketonurias by sharing your contact details with the study coordinator.