CLINICAL
In this dose escalation study, investigators to date have observed three confirmed partial responses and four instances of long-lasting stable disease. These patients had a median of two lines of prior therapy (range 1-6). In addition, SOT101 in combination with pembrolizumab was generally well tolerated. Dose escalation in this study is ongoing.
A SOT101 monotherapy arm of the study demonstrated encouraging efficacy signals in the 30 patients with advanced/metastatic solid tumors, including in CPI refractory patients. To date, there has been one confirmed clinical and radiological response and confirmed stable disease in four patients. Additionally, one patient had a partial response on SOT101+pembrolizumab combination therapy after experiencing a relapse on SOC101 monotherapy.
SOT101 was well tolerated, and the majority of treatment emergent adverse events were Grade 2 or less. Patients in this dose escalation study have had a median of three lines of prior therapy (range 1-9). The recommended Phase 2 dose has been defined at 12 μg/kg and a Phase 2 monotherapy expansion study at this dose is ongoing in selected tumor indications.
Glycotopepresents new data on carbohydrate-dependent antibodies and fusion-proteins at SITC
Glycotope, a biotechnology company developing antibodies against proteins carrying tumor-specific carbohydrate structures, announced it is presenting new data at SITC. GT-00A x IL15, a TA-MUC1-targeting IL-15 fusion antibody is one of the first tumor-targeted immuno-cytokines. The preclinical data showed that IL-15 immuno-cytokine has the potential to significantly outperform non-targeted IL-15 immuno-cytokines offering a highly needed alternative in the treatment of several solid-tumor indications.
Systemic IL-15 promotes allogeneic cell rejection in patients treated with NK cell adoptive therapy
NK cells are a promising alternative to T cells for cancer immunotherapy. Adoptive therapies with allogeneic, cytokine-activated NK cells are being investigated in clinical trials. However, the optimal cytokine support after adoptive transfer to promote NK cell expansion, and persistence remains unclear. Correlative studies from two independent clinical trial cohorts treated with MHC-haploidentical NK cell therapy for relapsed/refractory AML revealed that cytokine support by systemic IL-15 (N-803) resulted in reduced clinical activity, compared to IL-2. It was hypothesized that the mechanism responsible was IL-15/N-803 promoting recipient CD8 T cell activation that in turn accelerated donor NK cell rejection. This idea was supported by increased proliferating CD8+ T cell numbers in patients treated with IL-15/N-803, compared to IL2. Moreover, mixed lymphocyte reactions showed that IL-15/N-803 enhanced responder CD8 T cell activation and proliferation, compared to IL-2 alone. Additionally, IL-15/N-803 accelerated the ability of responding T cells to kill stimulator-derived ML NK cells, demonstrating that additional IL-15 can hasten donor NK cell elimination. Thus, systemic IL-15 used to support allogeneic cell therapy may paradoxically limit their therapeutic window of opportunity and clinical activity. This study indicates that stimulating patient CD8 T cell allo-rejection responses may critically limit allogeneic cellular therapy supported with IL-15.
