In the United States, the Orphan Drug Act was established to incentivize drug developers and other stakeholders to begin developing therapies for rare diseases. Orphan Drug designation is now granted to drugs or biologics which intend to treat, diagnose, or prevent rare and life-threatening conditions, defined as those affecting fewer than 200,000 Americans. As incentives, drug developers whose therapies receive this status are granted fee waivers, tax credits, and seven years of market exclusivity upon approval.

In a news release from immuno-oncology company ALX Oncology Holdings Inc., the company shared that its therapy evorpacept was granted Orphan Drug designation for the treatment of acute myeloid leukemia (AML). Previously, evorpacept also earned this designation for the indication of gastric cancer.

Evorpacept: An Overview

On the company website, ALX Oncology Holdings Inc. explains that CD47 is a myeloid checkpoint target. As the company shares:

By overexpressing CD47, cancer cells are able to avoid phagocytosis by macrophages and thereby evade subsequent detection by the adaptive immune system. High CD47 expression in cancer cells has been shown to be a prognostic indicator of decreased survival in multiple oncology indications.

In short, the cancer cells overexpress CD47, sending out a “don’t eat me” signal and avoiding immune detection. Evorpacept works by blocking CD47, allowing the immune system to more easily find and destroy cancer cells.

Moving forward, ALX Oncology Holdings Inc. aims to evaluate evorpacept, in conjunction with azacitidine and venetoclax, for those with treatment-naïve acute myeloid leukemia within the Phase 1/2 ASPEN-05 clinical trial.

What is Acute Myeloid Leukemia (AML)?

Acute myeloid leukemia (AML) is a rare blood and bone marrow cancer. Damage to the DNA of developing cells causes AML. This damage causes immature cells to develop into leukemic myeloblasts, reducing bone marrow function and causing health problems. Additionally, these leukemic cells crowd out healthy red and white blood cells, as well as platelets. Radiation, chemotherapy, and chemical exposure increase the risk of developing AML. Unfortunately, AML is a fast-progressing cancer. In those over 20 years old, the 5-year survival rate sits around 27%.

Symptoms associated with acute myeloid leukemia can include:

• Bone pain
• Lethargy and fatigue
• Pallor (pale skin)
• Fever
• Frequent infections
• Easy bruising and bleeding
• Excessive sweating
• Unintended weight loss
• Frequent nosebleeds or other unusual bleeding