Protara Therapeutics, Inc. announced that it has received regulatory clearance from the U.S. Food and Drug Administration (FDA) on its planned Phase 2 STARBORN-1 trial evaluating TARA-002, an investigational cell-based immunopotentiator, for the treatment of pediatric patients with lymphatic malformations (LMs). Trial initiation is expected in the fourth quarter of 2023. STARBORN-1 is a Phase 2 single-arm, open-label, prospective clinical trial to evaluate the safety and efficacy of intracystic injection of TARA-002 for the treatment of macrocystic and mixed cystic LMs (= 50% macrocystic disease) in participants six months to less than 18 years of age.

Following completion of an age de-escalation safety lead-in, the trial will enroll approximately 30 patients who will 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 LMs and mixed cystic LMs who demonstrated clinical success, defined as having either a complete response (90% to 100% reduction from baseline in total LM volume) or substantial response (60% to less than 90% reduction in total LM volume) eight weeks after the last injection, as measured by axial imaging. TARA-002 is an investigational cell therapy based on the broad immunopotentiator, OK-432, which was originally granted marketing approval by the Japanese Ministry of Health and Welfare as an immunopotentiating cancer therapeutic agent.

This cell therapy is currently approved in Japan and Taiwan for LMs and has been used to successfully treat thousands of pediatric patients. In addition, OK-432 was studied in the largest ever conducted Phase 2 trials in LMs, in which the therapy was administered via a now-closed compassionate use program led by the University of Iowa to over 500 pediatric and adult patients in the United States. TARA-002 has been granted Rare Pediatric Disease designation by the FDA for the treatment of LMs. TARA-002 is an investigational cell therapy in development for the treatment of NMIBC and of LMs for which it has been granted Rare Pediatric Disease Designation by the U.S. Food and Drug Administration.

TARA-002 was developed from the same master cell bank of genetically distinct group A Streptococcus pyogenes as OK-432, a broad immunopotentiator marketed as Picibanil® in Japan and approved in Taiwan by Chugai Pharmaceutical Co. Ltd. Protara has successfully shown manufacturing comparability between TARA-002 and OK-432. When TARA-002 is administered, it is hypothesized that innate and adaptive immune cells within the cyst or tumor are activated and produce a strong immune cascade.

Neutrophils, monocytes and lymphocytes infiltrate the abnormal cells and various cytokines, including interleukins IL-2, IL-6, IL-8, IL-10, IL-12, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha are secreted by immune cells to induce a strong inflammatory reaction and destroy the abnormal cells.