Towards a mechanistic understanding of patient response to neoadjuvant SBRT with anti-PDL1 in human HPV-unrelated locally advanced HNSCC: Phase I/Ib trial results (Part 1)
Project description:Five-year survival for HPV-unrelated head and neck squamous cell carcinomas (HNSCC) remains below 50%. We assessed the safety of administering combination hypofractionated stereotactic body radiation therapy (SBRT) with anti-PDL-1 neoadjuvantly followed by adjuvant anti-PDL-1 with standard of care therapy (n=21) (NCT03635164). The primary endpoint of the study was safety, which was met. Secondary endpoints included radiographic, pathologic, and objective response, locoregional control (LRC), progression-free survival (PFS), and overall survival (OS). Among evaluable patients at early median follow-up of 16 months (448 days, or 64 weeks), OS was 80.1% with 95% C.I. (62.0%, 100.0%), LRC and PFS were 75.8% with 95% C.I. (57.5%, 99.8%), and major pathological response (MPR) or complete response (CR) was 75% with 95% exact C.I. (51.6%, 100%). Circulating CD8/Treg ratio, CD4 effector memory T cells, and TCR repertoire at time of surgery emerged as biologic correlates of response to therapy. Using high-dimensional multi-omics and spatial data as well as biological correlatives pre- and post-treatment, three major changes were noted in responders within the tumor microenvironment (TME) (and within the blood) post-treatment: 1) an increase in effector T cells; 2) a decrease in immunosuppressive cells; and 3) an increase in antigen presentation. Non-responders appeared to fail due to a lack of one of these three identified steps needed for priming and maintaining activation of T cells. Multiple correlates for response, along with subsets of non-responders that may benefit from additional or alternative immunotherapies, were identified. This treatment is being tested in an ongoing phase II trial with a similar design, where we hope to confirm and expand on our understanding of the mechanisms underlying resistance to therapy.
Project description:Towards a mechanistic understanding of patient response to neoadjuvant SBRT with anti-PDL1 in human HPV-unrelated locally advanced HNSCC: Phase I/Ib trial results
Project description:Five year survival rates for pancreatic cancer remain low, around 11%. We assessed differential gene expression between SBRT responders and non-responders as well as expression pre and post SBRT. Samples were obtained from the University of Colorado biorepository. All patients had borderline resectable pancreatic cancer, treated with neoadjuvant chemotherapy followed by restaging, and treatment with 30–33.6 Gy SBRT to pancreatic tumors, followed by pancreaticoduodenectomy and adjuvant chemotherapy. We observed increases in PDL1, PD1, CD25, and a decrease in CD122 expression following RT. Furthermore, we found that responders to SBRT exhibit decrased CD25 expression with increased CD122 and CD132 expression compared to non-responders. Using GSEA of responders vs. non-responders, we found responders to SBRT exhibit enrichment of inflammatory response, IFN signaling, and IL2/STAT5 signaling.
Project description:Vα24-invariant natural killer T cells (NKTs) have antitumor properties that can be enhanced by transgenic expression of tumor-specific receptors. Here, we report the results of the first-in-human clinical evaluation of autologous NKTs co-expressing a GD2-specific chimeric antigen receptor with interleukin (IL)15 (GD2-CAR.15) in 12 children with neuroblastoma (NB) treated on four dose levels (NCT03294954). Objectives included assessing safety, antitumor activity, and immune response. No dose-limiting toxicities occurred, and one patient had grade 2 cytokine release syndrome resolved by tocilizumab. The overall response rate was 25% (3/12) and disease control rate was 58% (7/12) including four patients with stable disease, two partial responses, and one complete response. CD62L+ NKT frequency in infused products correlated with CAR-NKT expansion in patients and was higher in responders than non-responders (71% vs 35.3%, p=0.002). Singe-cell RNA sequencing analysis identified B cell translocation gene 1 (BTG1) as one of the top upregulated genes in GD2-CAR.15-NKTs after in vitro serial tumor challenge. Genetic gain- and loss-of-function experiments revealed that BTG1 is a key driver of hyporesponsiveness in exhausted NKT and T cells. Crucially, NKTs co-expressing GD2-CAR.15 and BTG1-specific shRNA eradicated metastatic NB in mice. These results indicate that CAR-NKTs are safe, produce objective responses in NB patients, and that targeting BTG1 can enhance their therapeutic potency.