Intratumoral T cell clonality and survival in a randomized phase II study of preoperative autophagy inhibition in combination with gemcitabine and nab-paclitaxel treatment in patients with resectable pancreatic cancer.

Abstract

e16001 Background: Autophagy is a cell survival mechanism that is upregulated in pancreatic ductal adenocarcinoma (PDAC). PDAC autophagy results in an altered metabolic phenotype that promotes tumor progression, chemotherapeutic resistance, and immune evasion. Methods: We previously completed a randomized phase II clinical trial of preoperative gemcitabine-nab-paclitaxel with (PGH n = 34) and without (PG, n = 30) autophagy inhibition in patients with resectable and borderline resectable PDAC, which demonstrated increased Evans Grade histopathologic and serum CA 19-9 response with autophagy inhibition (IRB 13-074, NCT01128296 ). Utilizing the resected FFPE tumor specimens from evaluable patients, we completed paired multiplex immunohistochemistry (CD4, CD8, FOXP3, CD20, CD68, Pan-CK) and T & B cell receptor RNA sequencing to assess the intratumoral adaptive immune response and correlates of outcome. Results: Autophagy inhibition increased the number of infiltrating CD8 T cells (1133±490 vs 712±460 average cells per high power field, p = 0.01), CD8:CD20 ratio (2.22±3.1 vs 0.96±1.1, p = 0.02) and reduced the CD4:CD8 ratio (2.04±0.87 vs 3.01±2.09, p = 0.03). No effect was observed on the number of immature or mature germinal center-like tertiary lymphoid structures (TLS), though the number of TLS correlated with increased infiltration of CD4 T cells (r = 0.40, p < 0.001), T-regulatory cells (r = 0.26, p = 0.03) and CD20 B cells (r = 0.65, p < 0.001). Although the total number of productive T and B cell receptors increased with autophagy inhibition (167217±105961 vs 97339±5,1628, p = 0.02), no apparent effects were observed on Vαβ TCR or BCR IgH, Igκ, Igλ clonality. Independent of treatment, intratumoral CD8 counts were associated with an improved CA 19-9 response (r = 0.32, p = 0.04) and in a subset of short term ( < 2 years, n = 17) and long term ( > 4 years, n = 10) survivors (LTS), a lowered CD4:CD8 ratio was identified in LTS (1.83±0.63 vs 2.8±0.90, p = 0.01). Dominance of B cell receptors was a prominent feature of the immune repertoire in all patients (average expression: Vα 0.6%, Vβ 0.8%, IgH 18.9%, Igκ 32.3%, Igλ 47.2%) with an IgA skewed immunoglobulin class switching (mean 63% of all BCRs). Increased αβ T cell receptor clonality above the median level was associated with a CA 19-9 response (r = 0.37, p = 0.06) and greater overall survival (median OS 38.3 vs 19.3 months, p = 0.02), indicative of possible tumor specific clonal expansion. Conclusions: Preoperative autophagy inhibition increased the number of tumor infiltrating CD8 T cells in patients with localized pancreatic cancer. Intratumoral αβ T cell receptor clonality was associated with CA 19-9 response and improved overall survival. Combination treatment regimens increasing PDAC specific CD8 responses are warranted. Clinical trial information: NCT01978184.

Targeting autophagy as a therapeutic strategy against pancreatic cancer

“…Both compounds have been used in several clinical trials to target various cancers, including PDAC [116]. Although HCQ showed only minimal activity when used as monotherapy [126], HCQ plus GnP significantly improved the response rates compared with GnP alone (21% vs. 38%, p = 0.047) [127], showed an improved pathological response, and increased immune cell infiltration [103,104](NCT01978184), further confirming the role of autophagy as a key resistance mechanism against therapeutic treatment. Based on these findings, multiple clinical trials are ongoing to test the efficacy of combining autophagy/lysosome inhibitors (mainly HCQ) with conventional chemotherapy, targeted therapy, and ICB (Table 2).…”

“…In line with this, a recent clinical trial using HCQ and gemcitabine plus nabpaclitaxel (GnP), a standard-of-care chemotherapy for PDAC [102], as neoadjuvant chemotherapy (NCT01978184), showed that the addition of HCQ increased the number of tumor-infiltrating CD8 ? T cells [103,104]. Additionally, a recent study identified tumorcell-derived progranulin (PGRN) as a driver of autophagydependent MHC-I degradation and subsequent immune evasion [105].…”

Targeting the Metabolic Rewiring in Pancreatic Cancer and Its Tumor Microenvironment

“…In 2020, another randomized phase II trial was conducted to compare the efficacy of HCQ plus GnP and GnP alone in preoperative chemotherapy. An analysis of resected tumor specimens demonstrated an improved pathological response and increased tumor-infiltrating immune cells, including CD8 + T cells [ 138 , 139 ] (NCT01978184), supporting the role of autophagy as a driver of immune escape in PDAC [ 136 , 137 ]. Based on these findings, multiple clinical trials are ongoing to test the therapeutic efficacy of combining HCQ with conventional chemotherapy, molecular-targeted therapy, and ICB ( Table 1 ).…”

“…Importantly, genetic or pharmacological inhibition of autophagy restores cell surface MHC-I expression and antigen presentation in PDAC cells, leading to increased CD8 + T cell infiltration, reduced tumor burden, and improved response to ICB in syngeneic tumor transplant mouse models [ 136 , 137 ] ( Figure 5 ). Consistently, a recent clinical trial demonstrated that the addition of HCQ to gemcitabine plus nab-paclitaxel (GnP), a standard-of-care chemotherapy for PDAC [ 6 ], in the context of neoadjuvant chemotherapy leads to increased CD8 + T cell infiltration in resected tumors [ 138 , 139 ]. In line with these findings, a recent study identified cancer cell-derived progranulin (PGRN) as a driver of autophagy-dependent MHC-I degradation and subsequent immune evasion [ 140 ].…”