Handok affiliate Rezolute announced on January 7th (U.S. time) that the U.S. Food and Drug Administration (FDA) has designated RZ358 (Ersodetug), a treatment for hypoglycemia due to congenital hyperinsulinism (HI), as a Breakthrough Therapy.

The Breakthrough Therapy designation is designed to expedite the development and regulatory review of investigational treatments for serious or life-threatening conditions that, based on clinical evidence, have the potential to substantially improve clinical outcomes compared with available therapies.

The designation of RZ358 as a Breakthrough Therapy is based on the results of the Phase 2b (RIZE) study conducted on patients with congenital hyperinsulinism. The study showed that hypoglycemia was safely improved in over 75% of patients without clinically significant hyperglycemia.

Nevan Charles Elam, CEO and founder of Rezolute, stated, "2024 has been a transformative year for Rezolute, achieving significant clinical progress and meaningful advancements towards our mission to treat all forms of hyperinsulinism. The Breakthrough Therapy designation recognizes the potential of Ersodetug to provide therapeutic benefits to patients with hyperinsulinism. We plan to complete patient enrollment for the Phase 3 sunRIZE trial in congenital hyperinsulinism and announce topline results this year, while also progressing the Phase 3 trial for tumor-induced hyperinsulinism."

Rezolute is currently conducting Phase 3 trials for Ersodetug in two indications: congenital hyperinsulinism and tumor-induced hyperinsulinism. The global Phase 3 sunRIZE trial for congenital hyperinsulinism, including the U.S., is expected to announce topline results in the second half of this year. In 2024, Ersodetug received the Innovation Passport Designation from the UK's ILAP (Innovative Licensing and Access Pathway) for the treatment of hypoglycemia due to congenital hyperinsulinism.

Additionally, Rezolute reported preclinical validation of Ersodetug's potential use in treating hypoglycemia due to non-insulinoma pancreatogenous hypoglycemia syndrome (NICTs) in tumor-induced hyperinsulinism. This validation, combined with the clinical potential demonstrated in insulinomas and other islet cell tumors, could more than double the number of patients with tumor-induced hyperinsulinism who could be treated with Ersodetug. Rezolute received approval for the clinical trial plan for the Phase 3 study targeting hypoglycemia due to tumor-induced hyperinsulinism in 2024, with the trial set to begin in the first half of 2025 and key clinical results expected in the second half of 2026. Additionally, in November 2024, Ersodetug was designated as an orphan drug (ODD) by the FDA for the treatment of hypoglycemia due to tumor-induced hyperinsulinism. To date, more than 10 patients with tumor-induced hyperinsulinism have been successfully treated through the Expanded Access Program (EAP).

In June 2024, Rezolute successfully secured $73 million in funding to cover clinical and operational costs through the second quarter of 2026. Rezolute is a U.S. biotech venture developing targeted therapies for rare and metabolic diseases, including 'RZ358' for congenital hyperinsulinism and 'RZ402' for diabetic macular edema. Handok holds the commercialization rights for 'RZ358' and 'RZ402' in Korea and continues to collaborate with Rezolute on their development.