Immune-Onc Reports Promising Phase 1b IO-202 Results in CMML at 2024 ASH Meeting

Immune-Onc Therapeutics, Inc., a clinical-stage biopharmaceutical company, announced promising data from its Phase 1b clinical study of IO-202, a novel anti-LILRB4 antibody, in combination with azacitidine for patients with chronic myelomonocytic leukemia (CMML). These findings were presented at the 2024 American Society of Hematology Annual Meeting in San Diego, highlighting the potential impact of this treatment on a challenging cancer type with limited therapeutic options.

The trial assessed the efficacy of IO-202 alongside azacitidine in patients who had not previously received hypomethylating agents. Among 18 patients deemed evaluable for efficacy, the study demonstrated a complete remission (CR) rate of 50% and an overall response rate (ORR) of 66.7%, based on the 2023 International Working Group response criteria for higher-risk myelodysplastic syndromes. This outcome is significant, given that current treatments for CMML, particularly with hypomethylating agents, offer modest CR rates of only 7-17%.

A closer examination of the data revealed that the therapy was particularly effective in patients with high LILRB4 expression, where the CR rate was 83.3%, and the ORR reached 100%. These results were consistent across various subgroups, including those with more aggressive disease characteristics, such as elevated blast counts and adverse genetic mutations. The findings indicate that IO-202 could fill a substantial gap in CMML treatment, where few options exist and patient prognosis remains poor, with a median survival of under three years.

In addition to the efficacy outcomes, the treatment with IO-202 and azacitidine enabled 38.9% of the participants to transition successfully to allogenic hematopoietic cell transplantation (HCT), a procedure that offers the only potential cure but is an option for less than 15-20% of patients. Moreover, the study reported that four of six patients who were dependent on transfusions achieved independence, pointing to improvements in both clinical outcomes and quality of life.

The safety profile of IO-202 was also encouraging, with no dose-limiting toxicities observed at the recommended Phase 2 dose, which involves an initial administration of 60 mg/kg followed by 30 mg/kg bi-weekly. These findings support the advancement of IO-202 to further clinical trials, potentially establishing it as a frontline treatment for patients with CMML who are naïve to hypomethylating agents.

Gabriel N. Mannis, M.D., a principal investigator in the IO-202 Phase 1 trial, remarked on the promising nature of the results, emphasizing the potential of IO-202 to significantly enhance treatment outcomes for CMML patients, especially those with high LILRB4 expression. The therapy's ability to facilitate patient transitions to transplant and reduce transfusion dependency adds to its appeal as an innovative treatment option.

Charlene Liao, Ph.D., CEO of Immune-Onc, expressed optimism about the future development of IO-202, highlighting the data's support for a pivotal study as a frontline treatment. She conveyed the company's commitment to collaborating with regulatory bodies to provide this potentially transformative therapy to patients.

CMML is a rare blood cancer characterized by persistent elevation of blood monocytes and bone marrow dysplasia. Current FDA-approved treatments primarily involve hypomethylating agents like azacitidine, which yield limited success. IO-202, with its high-affinity binding to LILRB4, represents a promising targeted therapy, offering hope for improved outcomes in CMML and potentially other blood cancers and autoimmune diseases.