Adaptive Immune Resistance to Intravesical BCG in Non–Muscle Invasive Bladder Cancer: Implications for Prospective BCG-Unresponsive Trials

Abstract

Purpose: To characterize immune cell expression among patients with non-muscle invasive bladder cancer (NMIBC) treated with Bacillus Calmette-Guerin (BCG).Experimental Design: Patients with NMIBC treated with intravesical BCG (2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015) were identified, and a tissue microarray was constructed using paired pre-and post-BCG bladder samples. Among patients undergoing BCG, cystoscopic evaluation began 3 months after initiating BCG treatment to determine therapeutic response. IHC was performed for CD8, CD4, FoxP3, PD-L1 (SP-142 and 22C3), and PD-1. A full slide review of PD-L1 þ staining tumors was performed to characterize PD-L1 and CD8 colocalization. RNA-seq was performed on cored tumors from available specimens. We compared immune cell populations between BCG responders and nonresponders, and between pretreatment and postreatment tumor samples. Baseline PD-L1 staining in the BCG na€ ve population was then validated in a separate cohort. Results:The final cohort contained 63 pretreatment NMIBC cases, including 31 BCG responders and 32 BCG nonresponders. No differences in CD4, CD8, or FoxP3 expression were identified between responders and nonresponders. Baseline PD-L1 expression (22C3 and SP-142) was observed in 25% to 28% of nonresponders and 0% to 4% of responders (P < 0.01). PD-L1 þ cells in BCG nonresponders colocalized with CD8 þ T cells. In addition, BCG therapy did not increase PD-L1 gene expression (RNA-seq) or protein levels (IHC). The number of pretreatment CD4 þ T cells was very low among PD-L1 þ nonresponders (12%) and high among PD-L1 À nonresponders (50%, P < 0.01). In a separate cohort of 57 patients with NMIBC undergoing BCG, baseline PD-L1 (22C3) staining was similar (26%).Conclusions: One mechanism of BCG failure may be adaptive immune resistance. Baseline tumor PD-L1 expression predicts an unfavorable response to BCG and if validated, could be used to guide therapeutic decisions.

Programmed Cell Death-Ligand 1 Expression Status in Urothelial Carcinoma According to Clinical and Pathological Factors: A Multi-Institutional Retrospective Study

“…Meanwhile, positive PD-L1 expression was more common in patients that had received no intravesical BCG (29%) than in those that had (20%). This finding contradicts previous studies, which reported higher PD-L1 expression in BCG non-responders (including BCG relapsing tumors) than in BCG responders in non-muscle invasive bladder cancer (NMIBC) ( 30 , 31 ). This discrepancy may be due to a variety of reasons.…”

Evolution of Urothelial Bladder Cancer in the Context of Molecular Classifications

“…BCG failure refers to three different conditions: (1) BCG relapse, if the disease reoccurs after ≥6 months of disease-free survival, (2) BCG refractory, if the tumor persists after 6 months of treatment and (3) BCG intolerance, if the treatment has been discontinued due to toxic side effects of BCG [14,28,47]. Many factors can cause BCG failure, e.g., the presence of metastasis prior to therapy, inappropriate immune response or an adaptive immune resistance with overexpression of exhaustion markers (PD-1 and PD-L1) [48][49][50]. Although there is no standard of care for patients after BCG failure, radical cystectomy is considered the preferred treatment [25].…”

The prognostic value of programmed cell death protein ligand 1 in patients with non-muscle-invasive bladder cancer treated with bacille Calmette–Guérin immunotherapy: Current status

“…Only relevant five articles were identified in the literature to date. The characteristic and primary findings of available studies are summarised in Table 1 [6][7][8][9][10]. In an analysis of 22 patients with high-risk NMIBC, Martínez et al [6] found that pre-treatment PD-L1 expression did not differ significantly between patients classified as BCG 'responders' and 'non-responders', defined as patients without a recurrence or progression for ≥30 months after BCG treatment initiation.…”

“…Additionally, the authors showed that the PD-L1 expression was significantly increased after BCG installations compared to the pre-treatment level. In another paper, including patients with high-risk NMIBC, Kates et al [8] reported a significantly increased PD-L1 expression among pre-treatment samples collected from 32 BCG 'non-responders' (BCG unresponsive, relapsing progressors) compared to 31 'responders'. The positive PD-L1 expression was observed in 25-28% and 0-4%, respectively.…”