Potential role of botanical drug APG-157 as immune adjuvant in patients with oral squamous cell carcinoma.

Abstract

e17572 Background: Natural botanical drugs, such as curcumin, resveratrol and related flavonoids, are under clinical studies. Previous pilot study of curcumin, a polyphenol, for normal and patients with oral squamous cell carcinoma (OSCC) showed significant inhibition of inflammatory cytokines in saliva. Phase I investigation was performed on APG-157 to evaluate the potential utility an as oral drug for the treatment of OSCC. Methods: A double-blind, randomized, placebo-controlled phase I clinical trial was conducted with a botanical preparation containing a combination of curcumin related polyphenol molecules (pharmaceutical name APG-157). 12 Subjects with oral cancer and 13 normal control subjects were recruited. Two doses of the drug, 3x100 mg and 3x200 mg, were tested. The drug was administered orally each hour for 3 consecutive hours. Blood and saliva were collected pre-treatment and 1, 2, 3, and 24 hours post-treatment. Salivary cells and supernatants were analyzed for the expression of cytokines by multiplex ELISA and microbial content by 16S RNA sequence. Pre- and post-treatment tumor biopsies of one subject were studied for expression using the RNA seq and immunofluorescence (IF). Results: This study did not reveal any toxicity and there was a dose dependent inhibition of inflammatory cytokines, IL-1β, TNF-alpha and IL-8 in the salivary supernatant of cancer subjects treated with the drug. Tumor RNA-seq revealed down regulation of gene ontologies of cell adhesion, cell cycle and cell division and up regulation of generation of precursor metabolite/energy in the post-treatment tumor sample. Microbiome study showed significant decrease in Bacterioides after 24 hours of treatment. There was also a trend of decreasing Bacteroides among other cancer subjects treated with APG-157. IF showed a marked increase in the number of CD4, CD8 T cells in post-treatment tumor. PD-L1 expression was up-regulated in the post-treatment tumor sample. Conclusions: APG-157 is found to be safe and toxicity was not observed. The drug has shown a decrease in inflammatory cytokines. Moreover, there was a markedly increased CD4, CD8 T cells infiltration on a subject and decreased Bacteriodes microbial population after APG-157 treatment suggesting that it might have potential synergistic effect with immune checkpoint blockade immunotherapy. Decreased expression of cell growth related genes and increased expression of growth inhibitory genes pointed to a potential anti-tumor activity of APG-157.