Ligufalimab Earns FDA Orphan Drug Designation in AML

The FDA has granted orphan drug designation to ligufalimab (AK117) for the treatment of acute myeloid leukemia (AML).¹

Ligufalimab is a next-generation humanized IgG4 monoclonal antibody targeting CD47. Its design prevents red blood cell agglutination and has demonstrated improved safety and efficacy compared with other CD47-targeting agents.

Orphan drug designation is granted to therapies for rare diseases that affect fewer than 200,000 patients per year.² This designation means that Akesobio, the sponsor, is eligible for FDA guidance during development, tax incentives, and up to 7 years of market exclusivity upon approval.

Ligufalimab is being evaluated in hematologic malignancies as well as solid tumors.¹ Data presented at the 2023 American Society of Hematology (ASH) Annual Meeting showed that ligufalimab demonstrated an overall response rate (ORR) of 85.2% with a complete response rate (CR) of 48.1% among 27 evaluable patients with higher-risk myelodysplastic syndromes (HR-MDS).³ When patients received at least 3 cycles of treatment, the CR rate was 52%, and with at least 6 cycles of treatment, it was 68.4%. The median time to response was 0.97 months, with a median time to CR of 2.92 months.

Further, only 29.1% of patients treated with ligufalimab experienced anemia. Of 13 patients who required red blood cell transfusion due to anemia, 61.5% achieved transfusion independence.

In patients with AML, the composite CR rate was 55%, with 50% of patients achieving CR.

Looking ahead, a phase 2, randomized, double-blind, multicenter trial has recently completed enrollment, and will assess ligufalimab plus azacitidine in HR-MDS.¹

In solid tumors, 2 phase 3 studies are ongoing evaluating ligufalimab plus ivonescimab (SMT112) as a first-line treatment for PD-L1–positive head and neck squamous cell carcinoma and as a first-line therapy for pancreatic cancer.

REFERENCES:

1. Akeso’s Ligufalimab (CD47 mAb) Receives FDA Orphan Drug Designation for Acute Myeloid Leukemia (AML). News release. Akesobio. September 16, 2025. Accessed September 16, 2025. https://tinyurl.com/23tyrn64

2. Designating an Orphan Product: Drugs and Biological Products. US FDA. Updated August 12, 2024. Accessed September 16, 2025. https://tinyurl.com/5ckfaxtv

3. Akeso Published Results from CD47 Antibody Ligufalimab in Combination with Azacitidine for Newly Diagnosed Higher-Risk Myelodysplastic Syndrome and Treatment-naïve Acute Myeloid Leukemia at ASH 2023. News release. Akesobio. December 14, 2023. Accessed September 16, 2025. https://tinyurl.com/58y9rhuc