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Microbial Therapy

SYNB1934 for Phenylketonuria (SYNPHENY-3 Trial)

Phase 3
Waitlist Available
Research Sponsored by Synlogic
Eligibility Criteria Checklist
Specific guidelines that determine who can or cannot participate in a clinical trial
Must have
Age ≥ 18 years
Diagnosis of PKU and failure to maintain recommended blood Phe levels on existing management (sapropterin, sepiapterin and/or Phe-restricted diet), demonstrated by uncontrolled blood Phe level ≥ 360 μmol/L on current therapy any time during screening and uncontrolled blood Phe level ≥ 360 μmol/L on current therapy when taking the average of the 3 most recent Phe levels from the participant's medical history (inclusive of any screening values). All screening values must be obtained more than 7 days apart, as determined by central or local laboratory
Must not have
Currently taking Palynziq® (pegvaliase-pqpz) (within 1 month of screening)
A known or suspected diagnosis of DNAJC12 deficiency, biopterin synthesis deficiency, or irritable bowel syndrome
Timeline
Screening 3 weeks
Treatment Varies
Follow Up up to 15 weeks
Awards & highlights

Summary

This trial tests SYNB1934v1, a new treatment for people with high blood phenylalanine (Phe) levels. The goal is to find the best dose that reduces Phe levels by at least 20% without causing side effects.

Who is the study for?
Adults with Phenylketonuria (PKU) who haven't been able to control their blood Phe levels using current treatments can join. They should be on a stable diet and treatment for at least 1 month, agree to not change their diet or PKU management during the trial, and use contraception if applicable. Pregnant women, those on recent investigational drugs, antibiotics, or specific PKU therapies like Palynziq®, are excluded.
What is being tested?
The study tests SYNB1934v1's effectiveness in managing PKU over three parts: initial dose finding up to 15 weeks; a double-blind phase where participants randomly get either SYNB1934v1 or placebo for four weeks; followed by an open-label extension lasting up to three years.
What are the potential side effects?
Potential side effects of SYNB1934v1 aren't detailed here but may include reactions related to its ingredients such as E. coli Nissle or cinnamon. Participants with known allergies to these components are excluded from the trial.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below
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I am 18 years old or older.
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I have PKU and my blood Phe levels are too high despite current treatments.

Exclusion Criteria

You may be eligible for the trial if you check “No” for criteria below:
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I have been taking Palynziq® for the last month.
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I have been diagnosed with or suspected to have DNAJC12 deficiency, biopterin synthesis deficiency, or irritable bowel syndrome.
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I have received gene therapy for PKU.

Timeline

Screening ~ 3 weeks
Treatment ~ Varies
Follow Up ~up to 15 weeks
This trial's timeline: 3 weeks for screening, Varies for treatment, and up to 15 weeks for reporting.

Treatment Details

Study Objectives

Study objectives can provide a clearer picture of what you can expect from a treatment.
Primary study objectives
Mean Percent Change From DEP Baseline in Blood Phenylalanine (Phe) Level at Week 3 of iTD During the DEP
Secondary study objectives
Absolute Change From DEP Baseline in Blood Phe Level at Week 3 of iTD During the DEP
Number of Participants With a ≥ 20% Reduction From Baseline in Blood Phe Level at Any Time in the DEP

Trial Design

4Treatment groups
Experimental Treatment
Placebo Group
Group I: RWP (Part 2, SYNB1934v1)Experimental Treatment1 Intervention
Participants who completed the DEP were randomized 1:1 to receive SYNB1934v1 at their iTD established in the DEP orally immediately after meals. Participants remained on this dose of SYNB1934v1 for the duration of the RWP; doses of SYNB1934v1 were not permitted to be modified during the RWP.
Group II: OLE (Part 3, SYNB1934v1)Experimental Treatment1 Intervention
Participants completed a dose ramp to their iTD guided by tolerability, as described for the DEP, including the full dose-ramp schedule. The iTD in the OLE may have been different from the iTD in the DEP or RWP. The investigator may have escalated the dose of SYNB1934v1 up to 1 × 10\^12 live cells based on tolerability; multiple attempts to escalate to a higher dose level were permitted per investigator discretion.
Group III: DEP (Part 1, SYNB1934v1)Experimental Treatment1 Intervention
Participants received SYNB1934v1 orally immediately after meals on the following dose-ramp regimen: Dose level 1 (Days 1-9): 3 × 10\^11 live cells partial dose up to 3 times daily (TID); Dose level 2 (Weeks 4-6): 6 × 10\^11 live cells up to TID; Dose level 3 (Weeks 7-9): 1 × 10\^12 live cells up to TID.
Group IV: RWP (Part 2, Placebo)Placebo Group1 Intervention
Participants who completed the DEP were randomized 1:1 to receive placebo orally immediately after meals. Participants remained on the same dose of placebo for the duration of the RWP; doses of placebo were not permitted to be modified during the RWP.

Find a Location

Who is running the clinical trial?

SynlogicLead Sponsor
9 Previous Clinical Trials
422 Total Patients Enrolled

Media Library

SYNB1934 (Microbial Therapy) Clinical Trial Eligibility Overview. Trial Name: NCT05764239 — Phase 3
Phenylketonuria Research Study Groups: DEP (Part 1, SYNB1934v1), RWP (Part 2, SYNB1934v1), RWP (Part 2, Placebo), OLE (Part 3, SYNB1934v1)
Phenylketonuria Clinical Trial 2023: SYNB1934 Highlights & Side Effects. Trial Name: NCT05764239 — Phase 3
SYNB1934 (Microbial Therapy) 2023 Treatment Timeline for Medical Study. Trial Name: NCT05764239 — Phase 3
~16 spots leftby Sep 2025
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