iLeukon Therapeutics, Inc., a biotechnology firm based in San Diego, has announced that the U.S. Food and Drug Administration (FDA) has approved its Investigational New Drug (IND) application for a Phase II clinical trial. This study will investigate the efficacy of ILKN421H, an innovative mRNA-based therapy, in combination with pembrolizumab for the treatment of patients with advanced non-small cell lung cancer (NSCLC).
ILKN421H is a lipid nanoparticle (LNP)-formulated mRNA that encodes a non-alpha HSA–IL-2v fusion protein. Administered through intravenous injection every three weeks, this therapy has been shown to efficiently express mRNA in lymphoid organs while maintaining an extended half-life of approximately 20 hours for IL-2v. The unique design of ILKN421H selectively promotes the expansion of stem-like CD8 T and NK cells, enhancing their numbers significantly in patients.
In a first-in-human Phase I study (NCT05978102), ILKN421H demonstrated promising antitumor activity alongside a favorable safety profile, with no reported occurrences of vascular-leak syndrome or hypotension. This investigation involved 45 participants with advanced solid tumors and included evaluations of both monotherapy and combination therapy with pembrolizumab. Notably, the combination therapy yielded a confirmed objective response rate (ORR) of 80%, regardless of PD-L1 expression, with the median progression-free survival (PFS) still undetermined but expected to surpass 12 months.
Details from this Phase I trial will be shared in an oral presentation during the upcoming SITC Annual Meeting on November 8, 2025. Haining Huang, CEO of iLeukon Therapeutics, expressed optimism regarding ILKN421H, stating, “Next-generation IL-2 agents have been a major focus of the immuno-oncology field for the past decade. ILKN421H expands cytotoxic lymphocytes—CD8 T cells and NK cells—by up to five- and twenty-five-folds respectively, making it the first IL-2 based treatment to achieve this level of immune promotion safely.”
Huang further remarked on the potential of ILKN421H to enhance the effectiveness of checkpoint inhibitors like pembrolizumab and its applicability to future therapies, including tumor-infiltrating lymphocyte (TIL) and in vivo CAR-T approaches. With FDA approval for the Phase II trial, iLeukon is poised to further develop ILKN421H to address significant unmet medical needs and improve treatment outcomes for patients with NSCLC and possibly other cancers.
About iLeukon Therapeutics: Founded in 2020 and based in San Diego, California, iLeukon Therapeutics is a clinical-stage biopharmaceutical company focused on developing first-in-class IL-2-based mRNA therapies for cancer immunotherapy. The company”s pipeline includes ILKN421H in combination with checkpoint inhibitors and in vivo CAR-T strategies targeting solid tumors and B-cell lymphomas.
For further information, please contact: Brandon Nadres, PhD, Product Development Manager, iLeukon Therapeutics, at [email protected] or visit www.iLeukon.com.
