The future of immune checkpoint therapy Sharma, Padmanee; Allison, James P.
Science (American Association for the Advancement of Science),
04/2015, Volume:
348, Issue:
6230
Journal Article
Peer reviewed
Immune checkpoint therapy, which targets regulatory pathways in T cells to enhance antitumor immune responses, has led to important clinical advances and provided a new weapon against cancer. This ...therapy has elicited durable clinical responses and, in a fraction of patients, long-term remissions where patients exhibit no clinical signs of cancer for many years. The way forward for this class of novel agents lies in our ability to understand human immune responses in the tumor microenvironment. This will provide valuable information regarding the dynamic nature of the immune response and regulation of additional pathways that will need to be targeted through combination therapies to provide survival benefit for greater numbers of patients.
Immune checkpoint therapy has started a revolution in the field of oncology. The concept that the immune system plays a critical role in antitumor responses, which has been around for decades, has ...finally been proven and firmly established with elegant preclinical studies and dramatic clinical responses in patients as a result of antibodies that block inhibitory T-cell pathways. However, the clinical responses being achieved are only in a subset of patients, and more work is needed to provide a better understanding of the mechanisms that elicit tumor rejection, which will enable identification of appropriate biomarkers, reveal new targets, provide data to guide combination studies, and eventually dictate a platform that allows more patients to derive clinical benefit, including cures, with immune checkpoint therapy.
Cancer immunotherapy can induce long lasting responses in patients with metastatic cancers of a wide range of histologies. Broadening the clinical applicability of these treatments requires an ...improved understanding of the mechanisms limiting cancer immunotherapy. The interactions between the immune system and cancer cells are continuous, dynamic, and evolving from the initial establishment of a cancer cell to the development of metastatic disease, which is dependent on immune evasion. As the molecular mechanisms of resistance to immunotherapy are elucidated, actionable strategies to prevent or treat them may be derived to improve clinical outcomes for patients.
Cancer immunotherapy can induce long lasting responses in patients with metastatic cancers of a wide range of histologies. Broadening the clinical applicability of these treatments requires an improved understanding of the mechanisms limiting cancer immunotherapy. The interactions between the immune system and cancer cells are continuous, dynamic, and evolving from the initial establishment of a cancer cell to the development of metastatic disease, which is dependent on immune evasion. As the molecular mechanisms of resistance to immunotherapy are elucidated, actionable strategies to prevent or treat them may be derived to improve clinical outcomes for patients.
Immune checkpoint therapy with anti-CTLA-4 and anti-PD-1/PD-L1 has revolutionized the treatment of many solid tumors. However, the clinical efficacy of immune checkpoint therapy is limited to a ...subset of patients with specific tumor types
. Multiple clinical trials with combinatorial immune checkpoint strategies are ongoing; however, the mechanistic rationale for tumor-specific targeting of immune checkpoints is elusive. To garner an insight into tumor-specific immunomodulatory targets, we analyzed 94 patients representing five different cancer types, including those that respond relatively well to immune checkpoint therapy and those that do not, such as glioblastoma multiforme, prostate cancer and colorectal cancer. Through mass cytometry and single-cell RNA sequencing, we identified a unique population of CD73
macrophages in glioblastoma multiforme that persists after anti-PD-1 treatment. To test if targeting CD73 would be important for a successful combination strategy in glioblastoma multiforme, we performed reverse translational studies using CD73
mice. We found that the absence of CD73 improved survival in a murine model of glioblastoma multiforme treated with anti-CTLA-4 and anti-PD-1. Our data identified CD73 as a specific immunotherapeutic target to improve antitumor immune responses to immune checkpoint therapy in glioblastoma multiforme and demonstrate that comprehensive human and reverse translational studies can be used for rational design of combinatorial immune checkpoint strategies.
Summary Background Patients with metastatic urothelial carcinoma have a dismal prognosis and few treatment options after first-line chemotherapy. Responses to second-line treatment are uncommon. We ...assessed nivolumab, a fully human IgG4 PD-1 immune checkpoint inhibitor antibody, for safety and activity in patients with metastatic or surgically unresectable urothelial carcinoma whose disease progressed or recurred despite previous treatment with at least one platinum-based chemotherapy regimen. Methods In this multicentre, phase 2, single-arm study, patients aged 18 years or older with metastatic or surgically unresectable locally advanced urothelial carcinoma, measurable disease (according to Response Evaluation Criteria In Solid Tumors v1.1), Eastern Cooperative Oncology Group performance statuses of 0 or 1, and available tumour samples for biomarker analysis received nivolumab 3 mg/kg intravenously every 2 weeks until disease progression and clinical deterioration, unacceptable toxicity, or other protocol-defined reasons. The primary endpoint was overall objective response confirmed by blinded independent review committee in all treated patients and by tumour PD-L1 expression (≥5% and ≥1%). This trial is registered with ClinicalTrials.gov , number NCT02387996 , and is completed. Follow-up is still ongoing. Findings Between March 9, 2015, and Oct 16, 2015, 270 patients from 63 sites in 11 countries received nivolumab, and 265 were evaluated for activity. Median follow-up for overall survival was 7·00 months (IQR 2·96–8·77). Confirmed objective response was achieved in 52 (19·6%, 95% CI 15·0–24·9) of 265 patients. Confirmed objective response was achieved in 23 (28·4%, 95% CI 18·9–39·5) of the 81 patients with PD-L1 expression of 5% or greater, 29 (23·8%, 95% CI 16·5–32·3) of the 122 patients with PD-L1 expression of 1% or greater, and 23 (16·1%, 95% CI 10·5–23·1) of the 143 patients with PD-L1 expression of less than 1%. Grade 3–4 treatment-related adverse events occurred in 48 (18%) of 270 patients—most commonly grade 3 fatigue and diarrhoea, which each occurred in five patients. Three deaths were attributed to treatment (pneumonitis, acute respiratory failure, and cardiovascular failure). Interpretation Nivolumab monotherapy provided meaningful clinical benefit, irrespective of PD-L1 expression, and was associated with an acceptable safety profile in previously treated patients with metastatic or surgically unresectable urothelial carcinoma. Funding Bristol-Myers Squibb.
Summary Background Few effective treatments exist for patients with advanced urothelial carcinoma that has progressed after platinum-based chemotherapy. We assessed the activity and safety of ...nivolumab in patients with locally advanced or metastatic urothelial carcinoma whose disease progressed after previous platinum-based chemotherapy. Methods In this phase 1/2, multicentre, open-label study, we enrolled patients (age ≥18 years) with urothelial carcinoma of the renal pelvis, ureter, bladder, or urethra at 16 sites in Finland, Germany, Spain, the UK, and the USA. Patients were not selected by PD-L1 expression, but tumour PD-L1 membrane expression was assessed retrospectively. Patients received nivolumab 3 mg/kg intravenously every 2 weeks until disease progression or treatment discontinuation because of unacceptable toxicity or other protocol-defined reasons, whichever occurred later. The primary endpoint was objective response by investigator assessment. All patients who received at least one dose of the study drug were included in the analyses. We report an interim analysis of this ongoing trial. CheckMate 032 is registered with ClinicalTrials.gov , NCT01928394. Findings Between June 5, 2014, and April 24, 2015, 86 patients with metastatic urothelial carcinoma were enrolled in the nivolumab monotherapy group and 78 received at least one dose of treatment. At data cutoff (March 24, 2016), the minimum follow-up was 9 months (median 15·2 months, IQR 12·9–16·8). A confirmed investigator-assessed objective response was achieved in 19 (24·4%, 95% CI 15·3–35·4) of 78 patients. Grade 3–4 treatment-related adverse events occurred in 17 (22%) of 78 patients; the most common were elevated lipase (four 5%), elevated amylase (three 4%), and fatigue, maculopapular rash, dyspnoea, decreased lymphocyte count, and decreased neutrophil count (two 3% each). Serious adverse events were reported in 36 (46%) of 78 patients and eight (10%) had a serious adverse event judged to be treatment related. Two (3%) of 78 patients discontinued because of treatment-related adverse events (grade 4 pneumonitis and grade 4 thrombocytopenia) and subsequently died. Interpretation Nivolumab monotherapy was associated with a substantial and durable clinical response and a manageable safety profile in previously treated patients with locally advanced or metastatic urothelial carcinoma. These data support further investigation of nivolumab monotherapy in advanced urothelial carcinoma. Funding Bristol-Myers Squibb.
Immune checkpoint therapy (ICT) can provide durable clinical responses and improve overall survival. However, only subsets of patients with specific tumor types respond to ICT. Thus, significant ...challenges remain, including understanding pathways of resistance, optimizing patient selection, improving management of immune-related adverse events, and identifying rational therapeutic combinations. These challenges will need a focused approach encompassing both clinical and basic research, with the integration of reverse translational studies. This integrated approach will lead to identification of potential targets for subsequent clinical trials, which will guide decisions as we develop novel combination strategies to maximize efficacy and minimize toxicities for patients. SIGNIFICANCE: ICTs induce durable antitumor responses for subsets of patients with cancer. Recent evidence suggests that rational combinatorial strategies can improve response by overcoming primary and adaptive resistance mechanisms, although these may carry an increased risk of immune-mediated toxicities. This review surveys the current understanding of mechanisms of response and resistance to ICTs and active areas of investigation, and proposes a path forward to improving efficacy and minimizing toxicities through better patient selection and rational combinations.
The anti-CTL-associated antigen 4 (anti-CTLA-4) antibody ipilimumab is the first agent to show improved survival in a randomized phase III trial that enrolled patients with metastatic melanoma. ...Studies are ongoing to identify mechanisms that elicit clinical benefit in the setting of anti-CTLA-4 therapy. We previously reported that treated patients had an increase in the frequency of T cells expressing the inducible costimulator (ICOS) molecule, a T-cell-specific molecule that belongs to the CD28/CTLA-4/B7 immunoglobulin superfamily. ICOS and its ligand (ICOSL) have been shown to play diverse roles in T-cell responses such as mediating autoimmunity as well as enhancing the development/activity of regulatory T cells. These seemingly opposing roles have made it difficult to determine whether the ICOS/ICOSL pathway is necessary for antitumor responses. To determine whether the ICOS/ICOSL pathway might play a causal role in the antitumor effects mediated by anti-CTLA-4, we conducted studies in ICOS-sufficient and ICOS-deficient mice bearing B16/BL6 melanoma. We show that ICOS(+) T cells comprised a population of Th1 cytokine producing and tumor antigen-specific effector cells. Furthermore, in the absence of ICOS, antitumor T-cell responses elicited by anti-CTLA-4 are significantly diminished, thereby impairing tumor rejection. Our findings establish that the ICOS/ICOSL pathway is necessary for the optimal therapeutic effect of anti-CTLA-4, thus implicating this pathway as a target for future combinatorial strategies to improve the efficacy of anti-CTLA-4 therapy.
Immune-checkpoint blockade is able to achieve durable responses in a subset of patients; however, we lack a satisfying comprehension of the underlying mechanisms of anti-CTLA-4- and anti-PD-1-induced ...tumor rejection. To address these issues, we utilized mass cytometry to comprehensively profile the effects of checkpoint blockade on tumor immune infiltrates in human melanoma and murine tumor models. These analyses reveal a spectrum of tumor-infiltrating T cell populations that are highly similar between tumor models and indicate that checkpoint blockade targets only specific subsets of tumor-infiltrating T cell populations. Anti-PD-1 predominantly induces the expansion of specific tumor-infiltrating exhausted-like CD8 T cell subsets. In contrast, anti-CTLA-4 induces the expansion of an ICOS+ Th1-like CD4 effector population in addition to engaging specific subsets of exhausted-like CD8 T cells. Thus, our findings indicate that anti-CTLA-4 and anti-PD-1 checkpoint-blockade-induced immune responses are driven by distinct cellular mechanisms.
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•Anti-PD-1 and anti-CTLA-4 utilize distinct cellular mechanisms•T cell responses to different tumor models are fundamentally similar•Anti-PD-1 and anti-CTLA-4 both target subsets of exhausted-like CD8 T cells•CTLA-4 blockade induces expansion of ICOS+ Th1-like CD4 T cells
Anti-CTLA-4 and anti-PD-1 checkpoint-blockade therapies target distinct tumor-infiltrating T cell populations to induce tumor rejection.
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