First-in-Class Novel Therapy for Chronic Myelomonocytic Leukemia Granted FDA Orphan Drug Designation


Immune-Onc Therapeutics’ IO-202 is currently being analyzed as a monotherapy and in combination for patients with relapsed/refractory acute myeloid leukemia with monocytic differentiation or chronic myelomonocytic leukemia.

Image credit: Tada Images |

Image credit: Tada Images |

Immune-Onc Therapeutics’ novel therapy IO-202 has been granted orphan drug designation by the FDA to treat patients with chronic myelomonocytic leukemia (CMML).1 The first-in-class, humanized IgG1 antibody is currently being analyzed in a Phase I trial (NCT04372433) both as a monotherapy and in combination with Vidaza (azacitidine) with or without Venclexta (venetoclax) in patients with relapsed/refractory acute myeloid leukemia (AML) with monocytic differentiation or CMML.

“Although current therapeutic options for CMML can improve a patient’s quality of life, there is a high unmet need for effective disease-modifying approaches that are potentially curative,” Immune-Onc CEO and board chair Charlene Liao PhD, said in a news release. “We are very proud that the FDA has granted IO-202 orphan drug designation for the treatment of [patients with] CMML. We look forward to continued collaborations with our investigators and the FDA as we work to bring this potentially important therapy to patients with hard-to-treat blood cancers.”1

IO-202 was developed for high-affinity binding to leukocyte immunoglobulin-like receptor subfamily B4.1 Eligibility criteria for the multicenter, open-label trial included being at least 18 years of age, an ECOG performance status of 2 or lower, adequate hepatic and renal function, and not having received systemic calcineurin inhibitors for at least four weeks prior to administration of IO-202.2

During the dose-escalation portion of the trial, patients were administered intravenous IO-202 in dose levels that ranged from 0.03 mg/kg to 60 mg/kg on days one and 15 of each 28-day cycle, and administration of Vidaza at 75 mg/m2 on days one through seven of each cycle.

The trial’s primary endpoints were safety and tolerability of the novel agent both as a monotherapy and combined with Vidaza with or without Venclexta, with secondary endpoints that included pharmacokinetics, response rates, and incidence of antidrug antibodies against the study therapy.2

Investigators concluded that IO-202 was safe and well tolerated with promising efficacy at a maximum dose of 60 mg/kg twice weekly as monotherapy and combined with Vidaza.

IO-202 was granted Fast Track designation by the FDA in 2023 for patients with relapsed/refractory CMML.Further, IO-202 received FDA Fast Track designation in 2022 to treat patients with relapsed/refractory AML. In 2020, the FDA awarded the therapy with Orphan Drug designation for the same indication.1


1. Immune-Onc Therapeutics announces orphan drug designation granted by US FDA for IO-202 (anti-LILRB4) for the treatment of chronic myelomonocytic leukemia (CMML). News release. Immune-Onc Therapeutics, Inc. February 21, 2024. Accessed February 22, 2024.

2. IO-202 as monotherapy and IO-202 plus azacitidine ± venetoclax in patients in AML and CMML. Updated January 8, 2024. Accessed February 22, 2024.

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