THRIVE-3 Trial Advances: Protara's Choline Chloride Enters Pivotal Phase 3 Testing

Protara Therapeutics Inc. (TARA) has reached a significant milestone by enrolling its first patient into the landmark THRIVE-3 Phase 3 clinical trial. This groundbreaking study evaluates intravenous choline chloride as a potential solution for patients requiring extended parenteral support, marking a critical step toward addressing a widespread but largely overlooked medical challenge.

The Unmet Medical Need

Long-term parenteral support patients face a substantial burden—approximately 78% develop choline deficiency, a condition that triggers serious health complications including liver injury, neurological and psychological dysfunction, muscle deterioration, and blood clotting disorders. Remarkably, despite this prevalence, the global pharmaceutical landscape currently lacks any FDA-approved intravenous choline products, leaving clinicians without a sanctioned therapeutic option.

Trial Design and Scope

THRIVE-3 operates as a seamless Phase 2b/3 study framework. The initial phase involves an 8-week open-label dose-verification study across 24 patients, establishing optimal dosing parameters for choline chloride. Subsequently, approximately 105 additional patients will participate in a 24-week, double-blind, placebo-controlled phase 3 segment. The primary efficacy measure will assess changes in plasma choline concentration relative to baseline, compared against the placebo group. Patients who complete either phase remain eligible to continue into an open-label extension study evaluating sustained clinical outcomes.

Regulatory Pathway and Market Implications

The FDA has granted IV choline chloride Fast Track designation and Orphan Drug status, acknowledging the urgent medical need and commercial opportunity. These regulatory designations typically accelerate the review process and provide market exclusivity incentives, positioning this therapy to potentially become the first approved intravenous choline chloride treatment for this patient population.

Timeline and Stock Performance

An interim analysis is anticipated during the second half of 2026. In terms of market performance, TARA has fluctuated between $2.77 and $7.82 over the preceding 12 months, with the stock currently trading at $5.46, representing a 6.42% gain.