Protara Completes First Cohort in Phase 2 Trial of TARA-002 for Pediatric Lymphatic Malformations

Protara Therapeutics, Inc., a company at the clinical stage focused on developing transformative therapies for cancer and rare diseases, has announced the completion of the first cohort in its Phase 2 STARBORN-1 trial. This trial evaluates TARA-002, an investigational cell-based immunotherapy, for treating pediatric patients with lymphatic malformations (LMs). The company, listed on Nasdaq under the symbol TARA, is now enrolling patients in additional cohorts, with initial results expected in the first half of 2025.

Dr. Nancy Bauman, associated with the Children's National Medical Center in Washington DC and an investigator in the trial, highlighted the compelling initial data that mirrors the benefits observed in previous studies with OK-432, the precursor of TARA-002. She emphasized the urgent need for effective treatments for LMs, a rare condition predominantly affecting children, as there are currently no U.S. FDA-approved treatments available. Dr. Bauman expressed her optimism about TARA-002's potential to significantly impact the treatment landscape for LMs and looks forward to future findings from the study.

In the initial cohort, which included three patients aged between six and 18 years, two achieved complete response after just one dose of TARA-002. These responses were observed in one patient with a macrocystic lymphatic malformation and another with a ranula. The safety and tolerability profile was consistent with historical data from OK-432, with treatment-emergent adverse events (TEAEs) such as pain, swelling, fatigue, and increased body temperature. All TEAEs were mild to moderate and resolved over time.

Jesse Shefferman, CEO of Protara Therapeutics, expressed satisfaction with the trial's progress and the promising results so far. He noted that the company has received positive feedback from investigators and has a number of patients on waiting lists for the subsequent cohorts. Protara plans to share initial results from the next cohort in the first half of 2025.

The STARBORN-1 trial is a Phase 2, single-arm, open-label, prospective study focusing on the safety and efficacy of intracystic injection of TARA-002 for treating macrocystic and mixed cystic LMs in participants aged six months to less than 18 years. The trial aims to enroll around 30 patients, including age de-escalation safety lead-in cohorts for children aged six to less than 18 years, two to less than six years, and six months to less than two years. Each participant can receive up to four injections of TARA-002, spaced approximately six weeks apart.

The primary endpoint of the trial is the proportion of participants with macrocystic and mixed cystic LMs who achieve clinical success. Clinical success is defined as a complete response, characterized by a 90% to 100% reduction in LM volume from baseline, or a substantial response, marked by a 60% to less than 90% reduction in LM volume, as measured by axial imaging.

TARA-002 is based on OK-432, a broad immunopotentiator initially approved by the Japanese Ministry of Health and Welfare as a cancer therapeutic agent. OK-432 has been approved in Japan and Taiwan for LMs and has successfully treated thousands of pediatric patients. It was also studied extensively in the largest Phase 2 trials for LMs, led by the University of Iowa under a now-closed compassionate use program.

TARA-002 has been granted Rare Pediatric Disease designation by the U.S. FDA for treating LMs. Lymphatic malformations are rare, congenital malformations of lymphatic vessels, often diagnosed in early childhood, especially around the head and neck region. They can lead to severe complications, including airway obstruction, recurrent infections, and cosmetic and functional disabilities.

Protara Therapeutics remains committed to advancing treatments for cancer and rare diseases. Their portfolio includes TARA-002 for non-muscle invasive bladder cancer and LMs, as well as IV Choline Chloride for patients dependent on parenteral support.