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Radiation and dual checkpoint blockade activate non-redundant immune mechanisms in cancer.

Twyman-Saint Victor C, Rech AJ, Maity A, Rengan R, Pauken KE, Stelekati E, Benci JL, Xu B, Dada H, Odorizzi PM, Herati RS, Mansfield KD, Patsch D, Amaravadi RK, Schuchter LM, Ishwaran H, Mick R, Pryma DA, Xu X, Feldman MD, Gangadhar TC, Hahn SM, Wherry EJ, Vonderheide RH, Minn AJ - Nature (2015)

Bottom Line: Immune checkpoint inhibitors result in impressive clinical responses, but optimal results will require combination with each other and other therapies.Anti-CTLA4 predominantly inhibits T-regulatory cells (Treg cells), thereby increasing the CD8 T-cell to Treg (CD8/Treg) ratio.Addition of PD-L1 blockade reverses T-cell exhaustion to mitigate depression in the CD8/Treg ratio and further encourages oligoclonal T-cell expansion.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [2] Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.

ABSTRACT
Immune checkpoint inhibitors result in impressive clinical responses, but optimal results will require combination with each other and other therapies. This raises fundamental questions about mechanisms of non-redundancy and resistance. Here we report major tumour regressions in a subset of patients with metastatic melanoma treated with an anti-CTLA4 antibody (anti-CTLA4) and radiation, and reproduced this effect in mouse models. Although combined treatment improved responses in irradiated and unirradiated tumours, resistance was common. Unbiased analyses of mice revealed that resistance was due to upregulation of PD-L1 on melanoma cells and associated with T-cell exhaustion. Accordingly, optimal response in melanoma and other cancer types requires radiation, anti-CTLA4 and anti-PD-L1/PD-1. Anti-CTLA4 predominantly inhibits T-regulatory cells (Treg cells), thereby increasing the CD8 T-cell to Treg (CD8/Treg) ratio. Radiation enhances the diversity of the T-cell receptor (TCR) repertoire of intratumoral T cells. Together, anti-CTLA4 promotes expansion of T cells, while radiation shapes the TCR repertoire of the expanded peripheral clones. Addition of PD-L1 blockade reverses T-cell exhaustion to mitigate depression in the CD8/Treg ratio and further encourages oligoclonal T-cell expansion. Similarly to results from mice, patients on our clinical trial with melanoma showing high PD-L1 did not respond to radiation plus anti-CTLA4, demonstrated persistent T-cell exhaustion, and rapidly progressed. Thus, PD-L1 on melanoma cells allows tumours to escape anti-CTLA4-based therapy, and the combination of radiation, anti-CTLA4 and anti-PD-L1 promotes response and immunity through distinct mechanisms.

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Melanoma PD-L1 is associated with T cell exhaustion, response, and survival for patients treated on clinical trial of RT + anti-CTLA4a) Representative images (right) for patients with biopsies showing PD-L1 staining on tumor cells classified as PD-L1lo (top), 2+ (middle), or 3+ (bottom). Scores of 2+ and 3+ are classified as PD-L1hi. The arrow indicates PD-L1 staining on macrophages. An isotype antibody negative control and positive controls are shown (left). b) Changes in % Ki67+GzmB+ in PD-1+ CD8 T cells after RT + anti-CTLA4 vs. PD-L1 status on melanoma cells from all patients with available pre- and post-treatment blood. c) Changes in % Ki67+GzmB+ in PD1+Eomes+ CD8 T cells (left) or in PD1+ CD8 T cells (right) vs. macrophage PD-L1 status. d) Hazard ratio and 95% CI for PFS from a Cox regression model using PD-L1 status on tumor cells and macrophages. e) Model for non-redundant mechanisms and resistance to RT and immune checkpoint blockade.
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Figure 10: Melanoma PD-L1 is associated with T cell exhaustion, response, and survival for patients treated on clinical trial of RT + anti-CTLA4a) Representative images (right) for patients with biopsies showing PD-L1 staining on tumor cells classified as PD-L1lo (top), 2+ (middle), or 3+ (bottom). Scores of 2+ and 3+ are classified as PD-L1hi. The arrow indicates PD-L1 staining on macrophages. An isotype antibody negative control and positive controls are shown (left). b) Changes in % Ki67+GzmB+ in PD-1+ CD8 T cells after RT + anti-CTLA4 vs. PD-L1 status on melanoma cells from all patients with available pre- and post-treatment blood. c) Changes in % Ki67+GzmB+ in PD1+Eomes+ CD8 T cells (left) or in PD1+ CD8 T cells (right) vs. macrophage PD-L1 status. d) Hazard ratio and 95% CI for PFS from a Cox regression model using PD-L1 status on tumor cells and macrophages. e) Model for non-redundant mechanisms and resistance to RT and immune checkpoint blockade.

Mentions: In order to assess whether immune predictors discovered in mice could be shared with patients, we examined peripheral T cells and tumor biopsies from patients on our clinical trial of RT + anti-CTLA4. For all 10 patients with available pre- and post-treatment blood, two had PRs in unirradiated tumors and PFS significantly longer than the median. For both of these patients, the percentages of Ki67+GzmB+ increased in PD-1+Eomes+ CD8 T cells after treatment while the proportion of PD-1+Eomes+ T cells remained at or below the mean (Fig. 4b). In contrast, patients with a high percentage of PD-1+Eomes+ T cells post-treatment did not have PRs and had a short PFS, regardless of reinvigoration. Comparison of patient PT-402, who had extended PFS/PR (Fig. 1a–b), with patient PT-102, who had short PFS/PD, demonstrates how reinvigoration is associated with response to RT + anti-CTLA4 as it is in mice (Fig. 4c vs. Extended Fig. 5f–g and Fig. 3e–f). Examination of pre-treatment tumor biopsies from patients PT-402 and PT-102 (Fig. 4d), and from all patients with available biopsy (Extended Data Table 4), revealed that PD-L1lo intensity on melanoma cells (Extended Data Fig. 6a) was associated with reinvigoration of PD-1+Eomes+ and of PD-1+ CD8 T cells after RT + anti-CTLA4, while PD-L1hi status was associated with persistent exhaustion (Fig. 4e, Extended Data Fig. 6b). None of the patients with PD-L1hi on melanoma cells had a CR/PR, and all rapidly progressed and died (Fig. 4f–g). PD-L1 status on macrophages was neither associated with reinvigoration nor independently predictive of PFS (Extended Data Fig. 6c–d). Thus, collective results from patients and mice suggest that elevated PD-L1 on melanoma cells inhibits T cell function and tumor response to RT + anti-CTLA4.


Radiation and dual checkpoint blockade activate non-redundant immune mechanisms in cancer.

Twyman-Saint Victor C, Rech AJ, Maity A, Rengan R, Pauken KE, Stelekati E, Benci JL, Xu B, Dada H, Odorizzi PM, Herati RS, Mansfield KD, Patsch D, Amaravadi RK, Schuchter LM, Ishwaran H, Mick R, Pryma DA, Xu X, Feldman MD, Gangadhar TC, Hahn SM, Wherry EJ, Vonderheide RH, Minn AJ - Nature (2015)

Melanoma PD-L1 is associated with T cell exhaustion, response, and survival for patients treated on clinical trial of RT + anti-CTLA4a) Representative images (right) for patients with biopsies showing PD-L1 staining on tumor cells classified as PD-L1lo (top), 2+ (middle), or 3+ (bottom). Scores of 2+ and 3+ are classified as PD-L1hi. The arrow indicates PD-L1 staining on macrophages. An isotype antibody negative control and positive controls are shown (left). b) Changes in % Ki67+GzmB+ in PD-1+ CD8 T cells after RT + anti-CTLA4 vs. PD-L1 status on melanoma cells from all patients with available pre- and post-treatment blood. c) Changes in % Ki67+GzmB+ in PD1+Eomes+ CD8 T cells (left) or in PD1+ CD8 T cells (right) vs. macrophage PD-L1 status. d) Hazard ratio and 95% CI for PFS from a Cox regression model using PD-L1 status on tumor cells and macrophages. e) Model for non-redundant mechanisms and resistance to RT and immune checkpoint blockade.
© Copyright Policy - permissions-link
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4401634&req=5

Figure 10: Melanoma PD-L1 is associated with T cell exhaustion, response, and survival for patients treated on clinical trial of RT + anti-CTLA4a) Representative images (right) for patients with biopsies showing PD-L1 staining on tumor cells classified as PD-L1lo (top), 2+ (middle), or 3+ (bottom). Scores of 2+ and 3+ are classified as PD-L1hi. The arrow indicates PD-L1 staining on macrophages. An isotype antibody negative control and positive controls are shown (left). b) Changes in % Ki67+GzmB+ in PD-1+ CD8 T cells after RT + anti-CTLA4 vs. PD-L1 status on melanoma cells from all patients with available pre- and post-treatment blood. c) Changes in % Ki67+GzmB+ in PD1+Eomes+ CD8 T cells (left) or in PD1+ CD8 T cells (right) vs. macrophage PD-L1 status. d) Hazard ratio and 95% CI for PFS from a Cox regression model using PD-L1 status on tumor cells and macrophages. e) Model for non-redundant mechanisms and resistance to RT and immune checkpoint blockade.
Mentions: In order to assess whether immune predictors discovered in mice could be shared with patients, we examined peripheral T cells and tumor biopsies from patients on our clinical trial of RT + anti-CTLA4. For all 10 patients with available pre- and post-treatment blood, two had PRs in unirradiated tumors and PFS significantly longer than the median. For both of these patients, the percentages of Ki67+GzmB+ increased in PD-1+Eomes+ CD8 T cells after treatment while the proportion of PD-1+Eomes+ T cells remained at or below the mean (Fig. 4b). In contrast, patients with a high percentage of PD-1+Eomes+ T cells post-treatment did not have PRs and had a short PFS, regardless of reinvigoration. Comparison of patient PT-402, who had extended PFS/PR (Fig. 1a–b), with patient PT-102, who had short PFS/PD, demonstrates how reinvigoration is associated with response to RT + anti-CTLA4 as it is in mice (Fig. 4c vs. Extended Fig. 5f–g and Fig. 3e–f). Examination of pre-treatment tumor biopsies from patients PT-402 and PT-102 (Fig. 4d), and from all patients with available biopsy (Extended Data Table 4), revealed that PD-L1lo intensity on melanoma cells (Extended Data Fig. 6a) was associated with reinvigoration of PD-1+Eomes+ and of PD-1+ CD8 T cells after RT + anti-CTLA4, while PD-L1hi status was associated with persistent exhaustion (Fig. 4e, Extended Data Fig. 6b). None of the patients with PD-L1hi on melanoma cells had a CR/PR, and all rapidly progressed and died (Fig. 4f–g). PD-L1 status on macrophages was neither associated with reinvigoration nor independently predictive of PFS (Extended Data Fig. 6c–d). Thus, collective results from patients and mice suggest that elevated PD-L1 on melanoma cells inhibits T cell function and tumor response to RT + anti-CTLA4.

Bottom Line: Immune checkpoint inhibitors result in impressive clinical responses, but optimal results will require combination with each other and other therapies.Anti-CTLA4 predominantly inhibits T-regulatory cells (Treg cells), thereby increasing the CD8 T-cell to Treg (CD8/Treg) ratio.Addition of PD-L1 blockade reverses T-cell exhaustion to mitigate depression in the CD8/Treg ratio and further encourages oligoclonal T-cell expansion.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA [2] Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.

ABSTRACT
Immune checkpoint inhibitors result in impressive clinical responses, but optimal results will require combination with each other and other therapies. This raises fundamental questions about mechanisms of non-redundancy and resistance. Here we report major tumour regressions in a subset of patients with metastatic melanoma treated with an anti-CTLA4 antibody (anti-CTLA4) and radiation, and reproduced this effect in mouse models. Although combined treatment improved responses in irradiated and unirradiated tumours, resistance was common. Unbiased analyses of mice revealed that resistance was due to upregulation of PD-L1 on melanoma cells and associated with T-cell exhaustion. Accordingly, optimal response in melanoma and other cancer types requires radiation, anti-CTLA4 and anti-PD-L1/PD-1. Anti-CTLA4 predominantly inhibits T-regulatory cells (Treg cells), thereby increasing the CD8 T-cell to Treg (CD8/Treg) ratio. Radiation enhances the diversity of the T-cell receptor (TCR) repertoire of intratumoral T cells. Together, anti-CTLA4 promotes expansion of T cells, while radiation shapes the TCR repertoire of the expanded peripheral clones. Addition of PD-L1 blockade reverses T-cell exhaustion to mitigate depression in the CD8/Treg ratio and further encourages oligoclonal T-cell expansion. Similarly to results from mice, patients on our clinical trial with melanoma showing high PD-L1 did not respond to radiation plus anti-CTLA4, demonstrated persistent T-cell exhaustion, and rapidly progressed. Thus, PD-L1 on melanoma cells allows tumours to escape anti-CTLA4-based therapy, and the combination of radiation, anti-CTLA4 and anti-PD-L1 promotes response and immunity through distinct mechanisms.

Show MeSH
Related in: MedlinePlus