Personalized T-Cell Activator iTAC-XS15-CLL01 Demonstrates Safety and Immunogenicity in Phase 1 Chronic Lymphocytic Leukemia Trial
核心洞察
A phase 1 trial of iTAC-XS15-CLL01 (搜索), a personalized multipeptide T-cell activator, showed robust immune responses in 19 of 20 chronic lymphocytic leukemia (搜索) patients receiving BTK inhibitor therapy.
The treatment demonstrated an acceptable safety profile with no grade 4 adverse events or treatment-related serious adverse events, with most side effects being local injection site reactions.
Sustained T-cell responses persisted at six months follow-up in 84% of patients, with 90% showing reduced CLL cell populations compared to baseline.
A novel personalized T-cell activator has shown promising safety and immunogenicity results in patients with chronic lymphocytic leukemia (搜索) (CLL), according to data from a first-in-human phase 1 clinical trial published in The Lancet Haematology. The study evaluated iTAC-XS15-CLL01 (搜索), a warehouse-based multipeptide T-cell activator combined with Toll-like receptor 1/2 (搜索) ligand XS15, in patients receiving Bruton's tyrosine kinase (搜索) (BTK) inhibitor-based therapy.
Study Design and Patient Population
The open-label, single-center phase 1 trial enrolled 20 adults with CLL in Germany who had achieved at least partial remission with residual disease following 6-8 months of BTK inhibitor-based therapy. The median age was 56.5 years, and all participants were White. Most patients were male (70%) with Rai stage II disease (55%), Binet stage B (65%), unmutated IGHV status (80%), and no TP53 mutations (90%).
Participants received three monthly subcutaneous injections of iTAC-XS15-CLL01 (搜索), consisting of eight CLL-specific peptides selected according to individual HLA (搜索) allotyping, combined with XS15. Each dose contained 300 μg of each peptide plus 50 μg of XS15 emulsified in Montanide ISA 51 VG.
Safety Profile and Tolerability
The treatment demonstrated an acceptable safety profile with no grade 4 adverse events, treatment-related serious adverse events, or deaths reported during the study period. No patient discontinued the study due to treatment-related toxicity. The most frequent grade 3 adverse events were injection site erythema (15%), granuloma (10%), and ulceration (5%), all of which were local reactions.
Most adverse events occurred at low grades and typically consisted of vaccination-site complications, including grade 1/2 granuloma (90%), erythema (85%), and swelling (75%). Investigators reported no cytokine release syndrome higher than grade 1, immune effector cell-associated neurotoxicity syndrome, or any long-term immune-mediated medical conditions.
Immunogenicity and Clinical Activity
Robust T-cell responses were induced in 19 of 20 patients (95% CI, 75.1%-99.9%) by the end of treatment, targeting multiple peptides. The study showed higher induction of T-cell responses to CLL-related HLA (搜索) class II-restricted peptides compared to class I-restricted peptides from baseline to end of treatment.
These immune responses demonstrated durability, persisting at six months follow-up in 16 of 19 evaluable patients (84%), with increasing response intensity observed through the end of the study period. The rate of T-cell responses to peptides of HLA (搜索) class I and class II increased from 35% at the end of treatment to 42% at the end of the study.
Clinical Outcomes
All patients remained alive at the end of the study, and none experienced progression of CLL. Reduced CLL cell populations versus baseline occurred in 90.0% of patients (n = 18/20; 95% CI, 68.3%-98.8%), with a median decrease of 50.0% (IQR, 74.9%-21.9%) compared to baseline. According to exploratory analyses, higher reduction rates were reported in patients with CD4-positive T-cell responses or both CD4-positive and CD8-positive responses.
Clinical Implications and Future Directions
The findings demonstrate that personalized multipeptide T-cell activation is feasible in chronic lymphocytic leukemia (搜索) and can generate sustained immune responses even in patients receiving ongoing targeted therapy. As lead study author Jonas S. Heitmann, MD, from University Hospital Tübingen noted, "The safety and immunogenicity data established by this trial show that iTAC-XS15-CLL01 (搜索) is a promising therapeutic T-cell activator that warrants further evaluation, which will be addressed in an upcoming randomized trial."
The investigators conclude that iTAC-XS15-CLL01 (搜索) shows potential as a novel immunotherapeutic strategy in chronic lymphocytic leukemia (搜索) and warrants further investigation in phase 2 clinical trials to better define its efficacy and long-term clinical benefit. The therapeutic activation of tumor-specific T cells represents a potential strategy for achieving long-term disease control in CLL, which remains largely incurable despite major advances with BTK inhibitor-based regimens.