The passage of the Orphan Drug Act was an important step in creating an environment that supports rare disease research and drug development. This Act created Orphan Drug designation, a status granted to drugs or biologics being developed for rare disease indications. Rare diseases/conditions are those affecting fewer than 200,000 people nationwide. This status comes with incentives to drive drug development: fee waivers, tax credits, increased regulatory assistance, and seven years of market exclusivity upon drug approval. Fierce Biotech reports that, in March 2023, the FDA granted Orphan Drug status to NTLA-5001, a T cell therapy from Intellia Therapeutics that is designed to treat acute myeloid leukemia (AML). 

NTLA-5001 is an autologous T cell receptor therapy that takes an ex vivo approach. This means that cells are taken from the body, modified, and then administered back to the patient. NTLA-5001 targets the Wilms’ tumor antigen. This antigen is highly expressed by AML cells; it is also found in other solid tumors. 

NTLA-5001 was being evaluated in a Phase 1/2a clinic study. However, the study was terminated as Intellia moves to an allogeneic version of NTLA-5001 in clinical development.

About Acute Myeloid Leukemia (AML)

Also referred to as acute myelogenous leukemia, AML is a blood and bone marrow cancer. It is important to diagnose AML and begin treatment early, as this cancer may rapidly progress without treatment. Radiation, chemical exposure, smoking cigarettes, older age, and certain chemotherapy drugs increase the risk of developing AML. In acute myeloid leukemia, the bone marrow produces abnormal platelets, red blood cells, and/or white blood cells called myeloblasts. These abnormal cells don’t function the way that they should. They also crowd healthy blood cells out of the bone marrow, leading to some of the characteristic health effects like: 

• Fever
• Fatigue and lethargy
• Shortness of breath
• Pallor (extremely pale skin)
• Anemia (low red blood cell count)
• Frequent or recurrent infections
• Easy bruising and bleeding
• Bone pain

Treatments usually fall into two phases: remission induction therapy followed by consolidation therapy. These phases may include chemotherapy, Trisenox, ATRA, and stem cell transplants. Clinical studies are also exploring investigational treatments for AML which could, in the future, change the treatment landscape.