Chronic myelomonocytic leukemia (CMML) is a rare cancer that affects both the blood and bone marrow. Doctors don’t know exactly what causes CMML, though many hypothesize that an acquired genetic mutation is at play. In a smaller subset of cases, prior chemotherapy or radiation treatment can cause CMML to occur.
Symptoms of chronic myelonomoncytic leukemia include an enlarged spleen and/or liver; appetite loss; abdomen pain; easy bruising and bleeding; fever; unintentional weight loss; frequent and severe infections; and anemia (low red blood cell count).
Research is currently exploring the underlying biological basis of CMML, as well as potential therapeutic interventions. Currently, stem cell transplantation is the only cure for this cancer. Treatments are mainly designed to manage and relieve symptoms.
One potential therapy currently being developed for chronic myelomonocytic leukemia is IO-202. Immune-Onc Therapeutics, the drug’s developer, describes IO-202 as:
a first-in-class antagonist antibody targeting LILRB4 in Phase 1 clinical development for the treatment of AML, CMML and solid tumors [that] blocks the interaction of LILRB4 with multiple ligands, including ApoE and fibronectin…In hematologic malignancies, IO-202 has 3 mechanisms of action including activation of T cell cytotoxicity, reduction of leukemia tissue infiltration and ADCC or ADCP.
Immune-Onc Therapeutics, 2024, https://www.immune-onc.com/io-202
An Orphan Drug for CMML
On February 22, 2024, Kyle Doherty reported in OncLive that the U.S. Food and Drug Administration (FDA) granted Orphan Drug designation to IO-202 for the treatment of CLL. Orphan Drug designation is given to drugs/biologics intended to treat, diagnose, or prevent rare conditions affecting fewer than 200,000 people nationwide. This status comes with incentives for drug developers including fee waivers, tax credits, and seven years of market exclusivity upon approval.
The Orphan Drug designation comes following dose-escalation data from a Phase 1 therapy evaluating IO-202 for CMML or relapsed or refractory (R/R) acute myeloid leukemia (AML) with monocytic differentiation. In the study, researchers evaluated IO-202 as a monotherapy (used on its own) or in combination with either azacitidine (Vidaza) and/or venetoclax (Venclexta).
Trial participants received intravenously administered IO-202 in varying doses. Researchers found that, in those with CMML:
- One individual receiving 4.5mg/kg IO-202 on its own achieved a partial remission.
- Another individual, who received 9mg/kg IO-202, had long-lasting, durable clinical benefits.
- Finally, one individual receiving 60mg/kg saw an optimal response in the bone marrow with a long-lasting and durable response to treatment.
The researchers determined that IO-202 was safe to use and generally well-tolerated up to 60mg/kg twice each week. However, many individuals within the study experienced adverse treatment reactions. This led 16.1% of people receiving just IO-202, and 6.7% of people receiving IO-202 in combination with another therapy, to discontinue treatment. Some participants died during the course of the study, though no deaths are thought to be linked to IO-202 use.
You can read more about the study over at OncLive.
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chronic myelomonocytic leukemia IO-202 leukemia oncology Orphan Drug orphan drug designation
Last modified: March 18, 2024
