Travere's HARMONY Restarts After 20-Month Delay, Reads Out H2 2027
The Phase 3 pegtibatinase trial resumed dosing in early 2026 after its primary completion date slipped nearly two years, with a homocysteine-lowering bar the model rates 98.5% likely to hit but only 24.5% likely to matter clinically.
Executive Summary
- HARMONY paused enrollment in November 2024 and restarted dosing in early 2026, with Travere's CEO confirming the first new patient dosed under the restarted protocol; the primary completion date moved out 20 months, from December 2025 to August 2027, changing when a decision-grade signal can arrive.
- The trial measures change in plasma total homocysteine from baseline over weeks 6 to 12 against placebo in 70 patients; no effect-size threshold or statistical plan is disclosed, so the size of reduction needed to matter clinically remains undefined.
- The model rates the endpoint 98.5% likely to be met but only 24.5% likely to be clinically significant, and confidence on the endpoint-met read is labeled LOW, a gap that changes how much weight the probability alone should carry.
- No independent sponsor runs a comparable Phase 3 program in classical HCU; the only readthrough comparator, Aeglea's pegtarviliase, sits in Phase 1/2 for a broader homocystinuria population, so this readout will not be benchmarked against a same-stage rival result.
- The catalyst is more than a year away and the underlying trial just resumed after a near-two-year delay, so the near-term signal to watch is enrollment progress and completion-date stability rather than efficacy data.
The restart
Travere Therapeutics, Inc. confirmed the first new patient was dosed in the restarted Phase 3 HARMONY study of pegtibatinase, according to its May 4, 2026 first-quarter results Press ReleasePress ReleaseMay 4, 2026. CEO Eric Dube called it part of a 'transformative start to the year for Travere,' citing 'the advancement of pegtibatinase with the first new patient dosed in the restarted Phase 3 HARMONY study' alongside FILSPARI's FSGS approval Press ReleasePress ReleaseMay 4, 2026. The trial's status flipped from Active-not-recruiting back to Recruiting on May 8, 2026, after moving the opposite direction in November 2024. Alongside that reversal, the primary completion date moved from December 1, 2025 to August 1, 2027, a 20-month delay.
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
What the trial measures
HARMONY (NCT06247085) is a randomized, placebo-controlled Phase 3 study enrolling 70 patients aged 12 to 65 with classical HCU due to cystathionine beta synthase deficiency NCT06247085A Study to Investigate Efficacy and Safety of Pegtibatinase Compared With Placebo in Participants ≥12 to ≤65 Years of Age With Classical Homocystinuria (HCU) Due to Cystathionine Beta Synthase Deficiency Receiving Standard of Care TreatmentNCT06247085. The primary endpoint is change from baseline in plasma total homocysteine (tHcy) levels, measured from weeks 6 to 12 NCT06247085A Study to Investigate Efficacy and Safety of Pegtibatinase Compared With Placebo in Participants ≥12 to ≤65 Years of Age With Classical Homocystinuria (HCU) Due to Cystathionine Beta Synthase Deficiency Receiving Standard of Care TreatmentNCT06247085. Patients must show plasma tHcy of 80 micromol/L or higher at screening, with an allowance for up to 18 participants enrolled at 50 to under 80 micromol/L NCT06247085A Study to Investigate Efficacy and Safety of Pegtibatinase Compared With Placebo in Participants ≥12 to ≤65 Years of Age With Classical Homocystinuria (HCU) Due to Cystathionine Beta Synthase Deficiency Receiving Standard of Care TreatmentNCT06247085. No effect-size threshold, powering assumption, or statistical analysis plan appears in the available registry record, so the magnitude of reduction needed to be considered a clinical win is not defined.
The probability gap
The AppliedXL model rates the endpoint 98.5% likely to be met, but confidence on that figure is labeled LOW [AXL-MODEL]. The model's clinical-significance probability, which asks whether any statistical win would also translate into a benefit patients or regulators would treat as decision-grade, sits at only 24.5% [AXL-MODEL]. That 74-point gap between the two probabilities means a positive topline readout would not by itself settle whether pegtibatinase produces a change patients or regulators would treat as decision-grade. Regulatory-approval probability, at 45.2%, sits closer to the clinical-significance read than to the endpoint-met read, suggesting the model treats statistical significance and regulatory viability as distinct hurdles [AXL-MODEL].
The competitive landscape
No independent sponsor runs a Phase 3 program targeting homocysteine in classical HCU; the only other active trial in this indication is Travere's own long-term extension study, ENSEMBLE (NCT06431893). Aeglea Biotherapeutics' pegtarviliase, the nearest mechanism-matched program, targets a broader homocystinuria population in Phase 1/2 and is not classified as a direct comparator given the indication and phase mismatch. That leaves HARMONY without a same-stage rival result to benchmark against when data arrive.
Regulatory backdrop
Pegtibatinase already holds Fast Track, Breakthrough Therapy, Rare Pediatric Disease, and Orphan Drug designations in the US, plus Orphan Drug status in the EU, all granted September 26, 2024. No FDA approval history exists yet for the drug, leaving no prior regulatory decision to use as a benchmark for how the agency might weigh this Phase 3 result.
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.