Purpose:

On the basis of preclinical evidence of epigenetic contribution to sensitivity and resistance to immune checkpoint inhibitors (ICI), we hypothesized that guadecitabine (hypomethylating agent) and atezolizumab [anti–programmed cell death ligand 1 (PD-L1)] together would potentiate a clinical response in patients with metastatic urothelial carcinoma (UC) unresponsive to initial immune checkpoint blockade therapy.

Patients and Methods:

We designed a single arm phase II study (NCT03179943) with a safety run-in to identify the recommended phase II dose of the combination therapy of guadecitabine and atezolizumab. Patients with recurrent/advanced UC who had previously progressed on ICI therapy with programmed cell death protein 1 or PD-L1 targeting agents were eligible. Preplanned correlative analysis was performed to characterize peripheral immune dynamics and global DNA methylation, transcriptome, and immune infiltration dynamics of patient tumors.

Results:

Safety run-in enrolled 6 patients and phase II enrolled 15 patients before the trial was closed for futility. No dose-limiting toxicity was observed. Four patients, with best response of stable disease (SD), exhibited extended tumor control (8–11 months) and survival (>14 months). Correlative analysis revealed lack of DNA demethylation in tumors after 2 cycles of treatment. Increased peripheral immune activation and immune infiltration in tumors after treatment correlated with progression-free survival and SD. Furthermore, high IL6 and IL8 levels in the patients’ plasma was associated with short survival.

Conclusions:

No RECIST responses were observed after combination therapy in this trial. Although we could not detect the anticipated tumor-intrinsic effects of guadecitabine, the addition of hypomethylating agent to ICI therapy induced immune activation in a few patients, which associated with longer patient survival.

This content is only available via PDF.
©2023 The Authors; Published by the American Association for Cancer Research
2023
American Association for Cancer Research
This open access article is distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) license.
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License .
Attribution-NonCommercial-NoDerivatives

Supplementary data

Supplementary Tables 1

Supplementary TablesSupplementary Table 1: Patient and tumor sample informationSupplementary Table 2: Tumor mutation burdenSupplementary Table 3: Unfiltered whole exome sequencing mutation analysisSupplementary Table 4: Filtered whole exome sequencing mutation analysisSupplementary Table 5: Immunohistochemistry scores of tumorsSupplementary Table 6: FACS panel for PBMC analysisSupplementary Table 7: Geometric mean fluorescence intensity (GMFI) from PBMC FACSSupplementary Table 8: Representativeness of Study Participants

- xlsx file
Figure S1

Supplementary Figure 1: Patient recruitment and sample collection overview.

- docx file
Figure S2

Supplementary Figure 2: Modest treatment-induced DNA methylation changes in UC tumors.

- docx file
Figure S3

Supplementary Figure 3: Copy number variation detected by SeSAMe from DNA methylation data.

- docx file
Figure S4

Supplementary Figure 4: Weak correlation of TE expression induction with DNA methylation change and viral mimicry activation.

- docx file
Figure S5

Supplementary Figure 5: Overall tumor mutation burden and frequency of mutations in cancer-associated genes in UC tumors.

- docx file
Figure S6

Supplementary Figure 6: Gene Set Enrichment Analysis reveals immune-related pathways discriminate PD and SD tumors.

- docx file
Figure S7

Supplementary Figure 7: Representative IHC staining of additional PD and SD tumors in pre-treatment and post-treatment timepoint from additional patients.

- docx file
Figure S8

Supplementary Figure 8: PD-L1 levels in tumor or tumor microenvironment does not associate with tumor progression or control.

- docx file
Figure S9

Supplementary Figure 9: CD8 infiltration in tumor is associated with survival.

- docx file
Figure S10

Supplementary Figure 10: Peripheral immune cell dynamics induced by combination therapy.

- docx file
Figure S11

Supplementary Figure 11: Peripheral immune cells are activated mid-treatment cycle.

- docx file
Figure S12

Supplementary Figure 12: HLA-DR and NKG2D abundance on peripheral lymphocytes associate with longer progression free survival.

- docx file