ABL Bio announced in a regulatory filing on the 28th that it has received additional approval from the Korean Ministry of Food and Drug Safety (MFDS) regarding a change to the Phase 1 clinical trial plan (IND) for its bispecific antibody immuno-oncology drug 'ABL503.'

This announcement is a corrective disclosure regarding the clinical trial plan amendment approval previously announced on July 9. At the time, the approving authority was listed only as the U.S. Food and Drug Administration (FDA); however, as Korea's MFDS was subsequently added, the company took follow-up measures. According to the company, it received approval for the clinical trial plan amendment from the MFDS dated July 28, 2026, and was informed of the fact through its representative.

Overview of the ABL503 Clinical Trial ABL503 is a bispecific antibody immuno-oncology drug targeting 4-1BB and PD-L1. It is a Phase 1 clinical trial evaluating the safety, tolerability, and anti-tumor activity of monotherapy and combination therapy in patients with advanced or metastatic solid tumors. This trial will be conducted at approximately eight institutions in the United States and Korea, and the clinical trial registration number is NCT04762641.

Key Contents of the IND Amendment The approved amendment includes the following three main items: • Monotherapy dose escalation and dose expansion part: to continue without changes from the existing plan • Monotherapy tumor expansion part: to modify the cancer types targeted in the existing trial • Combination therapy dose escalation and dose expansion part: to be newly initiated

Meanwhile, the estimated completion date for this clinical trial is January 31, 2028. ABL Bio plans to immediately submit relevant disclosures if the same clinical trial plan receives additional approvals from other countries or institutions in the future.