T-cell Checkpoint Blockade Research Articles

Profiling the dynamic expression of checkpoint molecules on cytokine-induced killer cells from non-small-cell lung cancer patients

Immune checkpoints associate with dysfunctional T cells, which have a reduced ability to clear pathogens or cancer cells. T-cell checkpoint blockade may improve patient survival. However, checkpoint molecules on cytokine-induced killer (CIK) cell, a non-specific adoptive immunotherapy, remain unknown. In present study, we detected the dynamic expression of eight major checkpoint molecules (CTLA-4, PD-1, PD-L1, TIM-3, CEACAM-1, LAG-3, TIGIT and BTLA) on CIK cells from NSCLC patients. The majority of these molecules, except BTLA, were sharply elevated during the early stage of CIK cell culture. Thereafter, PD-1 and TIGIT expressions decreased gradually towards the initial level (day 0). Moreover, CTLA-4 faded away during the later stage of CIK culture. LAG-3 expression decreased but was still significantly higher than the initial level. Of note, PD-L1 remained stably upregulated during CIK culture compared with PD-1, indicating that PD-L1 might act as an inhibitory molecule on CIK cells instead of PD-1. Furthermore, TIM-3 and CEACAM1 were strongly expressed simultaneously during long-term CIK culture and showed a significant and mutually positive correlation. BTLA displayed a distinct pattern, and its expression gradually decreased throughout the CIK culture. These observations suggested that CIK cells might be partly exhausted before clinical transfusion, characterized by the high expression of PD-L1, LAG-3, TIM-3, and CEACAM-1 and the low expression of TIGIT, BTLA, PD-1, and CTLA-4 compared with initial culture. Our results imply that implementing combined treatment on CIK cells before transfusion via antibodies targeting PD-L1, LAG-3, TIM-3, and CEACAM-1 might improve the efficiency of CIK therapy for NSCLC patients.

Retrospective analysis of patients with advanced melanoma treated with short course of anti-CTLA4 directly followed by anti-PD-1.

e21011Background: Combination of T-cell checkpoint blockade by anti-CTLA4 (ipilimumab, IPI) and anti-PD-1 (nivolumab, NIV) is one the most promising therapies in patients with late stage melanoma. It induces superior response rates (57.6%) as compared to single NIV (43.7%) or IPI (19.0%) therapy (Checkmate 067 study). This superior efficacy is, however, associated with a high percentage of ≥ grade 3 adverse events (AEs)(55.0% versus 16.3 and 27.3%). The combination therapy is currently not available in the Netherlands, which prompted physicians to treat patients with short-term IPI followed directly by NIV or pembrolizumab (PEM). Methods: In this retrospective analysis, patients were included who were treated with short-term IPI q3wk (two courses day 0 and 21), directly followed by anti-PD-1 (starting at day 22 and onwards depending on the schedule (every 2 wks for NIV and 3 wks for PEM)). Patients were analyzed for toxicity (% ≥ 3 grade AEs), best overall objective response rate (BORR) and disease contro...

SELECT-4: Phase I dose escalation trial of selumetinib (AZD6244, ARRY-142886) in combination with durvalumab (MEDI4736) in patients with advanced solid tumors.

TPS2607Background: Preclinical studies suggest that intermittent dosing with selumetinib, an oral, potent and highly selective, allosteric MEK1/2 inhibitor with a short half-life, should be evaluated in combination with durvalumab, a selective, high-affinity human IgG1 mAb, that blocks PD-L1 binding to PD-1 and CD80. Selumetinib may prime the immune response and also potentially inhibit T-cell function, thereby maximizing tumor cell damage and antigen presentation during the period of MEK inhibition; intermittent dosing with selumetinib will allow maximal relief of T-cell checkpoint blockade by durvalumab. The SELECT-4 study (NCT02586987) aims to evaluate this combination for the first time in pts. Methods: SELECT-4 is a Phase I, open-label, multicenter, dose escalation study investigating the safety and tolerability of intermittent doses of selumetinib combined with durvalumab in pts with advanced solid tumors for which no standard therapy exists. Selumetinib (starting dose 50 mg po bid, increasing until...

Abstract 5497: Cabozantinib eradicates de novo castrate-resistant PTEN/p53 deficient murine prostate cancer via activation of neutrophil-mediated anti-tumor innate immunity

Abstract The majority of kinase inhibitors in cancer clinical trials have been evaluated in the context of cell autonomous induction of apoptosis. However, apoptosis can result in protumorigenic immunosuppression, which limits the durability of an anti-tumor response. Recent clinical trial data shows striking clinical and radiographic responses with kinase inhibitor cabozantinib (XL-184) in metastatic solid tumors, particularly in the context of bone metastases. However, the mechanism responsible for this robust antitumor response remain unknown. Here we show that cabozantinib eradicates poorly differentiated invasive cancer that develop in the context of prostate-specific PTEN and p53 loss, respectively, within 48 hours of cabozantinib treatment. This rapid tumor clearance was temporally associated with infiltration of mature polymorphonuclear leukocytes into the tumor bed. These anti-tumor effects of cabozantinib appear to be MET-independent, since the MET inhibitor PF-04217903 did not phenocopy the effects of cabozantinib in the prostate-specific PTEN/p53 deficient mouse model in vivo. Unexpectedly, in vitro treatment of PTEN/p53 deficient cell lines derived from murine tumors showed insignificant apoptosis, but robust extracellular release of HMGB1, a neutrophil chemoattractant, and marker of immunogenic cell death. To elucidate the relevance of an immunogenic anti-tumor mechanism in vivo, we performed RNA-seq profiling and quantitative RT-PCR analysis, which showed an acute increase in anti-tumor inflammatory cytokine gene expression signature and neutrophil activation/chemotaxis markers following acute cabozantinib treatment. Critically, blockade of neutrophil chemotaxis/trafficking with dexamethasone or depletion with anti-Ly6G antibody, reversed the effects of cabozantinib towards eradication of advanced PTEN/p53 deficient tumors. Finally, cytokine array profiling of supernatant from bone marrow metastases from castrate-resistant prostate cancer patients showed increased neutrophil markers and decreased IL-6 levels within the bone microenvironment following 6 weeks of cabozantinib treatment., thus polarizing the neutrophils into” N1” effector cells. Collectively, these results shed light on a novel anti-tumor immunogenic mechanism for cabozantinib within the tumor microenvironment of PTEN/p53 deficient tumors, which unleashes a profound innate anti-tumor immune response. These findings suggest the possibility of combination therapies of cabozantinib with T-cell checkpoint blockade or vaccine-based approaches, to augment immunologic responses in advanced cancers. Citation Format: Akash Patnaik, Kenneth Swanson, Katja Helenius, Thornley Thomas, Athalia Pyzer, Vilmosne Csizmadia, Sabina Signoretti, Todd Morgan, Yugang Wang, Olivier Elemento, Lily Wang, Elena Levantini, John Clohessy, John Asara, David Smith, Jacalyn Rosenblatt, David Avigan, Steven Balk, Lewis Cantley. Cabozantinib eradicates de novo castrate-resistant PTEN/p53 deficient murine prostate cancer via activation of neutrophil-mediated anti-tumor innate immunity. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5497. doi:10.1158/1538-7445.AM2015-5497

72IN - Which Systemic Therapies Should Be Combined to Immunotherapy?

ABSTRACT Melanoma treatment by T cell checkpoint blockade (TcCB), e.g. anti-CTLA-4, PD-1, or PD-L1 mAbs, has largely contributed to the 2013 breakthrough of immunotherapy in medical science. In contrast to targeted therapies with high response rates, usually of short duration, immunotherapy benefits smaller groups of patients, but in case of response, these could be long-term and possibly curative. This raises the question whether and which systemic combination with TcCB can increase the response rate and subsequent the survival of melanoma patients. Several groups of systemic therapies have been tested/are currently tested in combination with TcCB: chemotherapy, angiogenesis inhibitors, targeted therapy, and immune modulators. Aside the reduction of tumor load (to bridge the time till onset of the immune response) several rationals have been postulated for the combination of TcCB with systemic therapies, e.g. induction of immunogenic cell death, synergistic breakdown of tumor vasculature, reduction of intra-tumor immune-inhibitory cells (Treg, MDSC), increased MHC and subsequent tumor antigen expression, reduced expression of T cell checkpoint molecules, and induction or broadening of the tumor specific T cell repertoire. So far most of the ideas are based on pre-clinical observations and are tested in phase 1/2 trials. Only the combination of DTIC and ipilimumab has been tested in a phase 3 trial. Unfortunately the missing comparator arm of single agent ipilimumab hampers the judgement of the net benefit of adding chemotherapy to CTLA-4 blockade. A phase 1 study testing the concurrent combination of selective BRAF inhibition (vemurafenib) and CTLA-4 blockade (ipilimumab) was closed for accrual due to unexpected toxicity. Testing combinations of targeting the MAPK pathway and TcCB inhibitiors at different schemes or with other compounds are currently underway, e.g. BRAF + /-MEK inhibition in combination with CTLA-4 blockade or BRAF inhibition in combination with PD-L1 blockade. In summary, TcCB is currently the most promising treatment approach in melanoma. Modulation of the tumor microenvironment, immunogenicity of the tumor cells itself, and the T cell repertoire will improve response rates and long-term outcome for patients treated with TcCB. Disclosure: C. Blank: Advisory role for BMS, MSD, Roche, Novartis, and GSK. Research funding from Novartis.

Phase I dose escalation study of recombinant interleukin-21 (rIL-21; BMS-982470) in combination with nivolumab (anti-PD-1; BMS-936558; ONO-4538) in patients (pts) with advanced or metastatic solid tumors.

TPS3112 Background: Programmed death-1 (PD-1) is an immune checkpoint receptor that attenuates T-cell activation by binding to its ligands, PD-L1 and PD-L2. Nivolumab, a PD-1 receptor blocking antibody, has shown durable antitumor activity in pts with various solid tumors in two phase I clinical trials. The cytokine rIL-21 has also shown antitumor activity in selected solid tumors. We hypothesized that combining rIL-21-induced stimulation of T-cell and NK-cell function in conjunction with T-cell checkpoint blockade using nivolumab could enhance biologic activity resulting in improved clinical outcomes, as compared with either agent alone. We describe a novel phase I study investigating the biologic activity and clinical outcomes of the combination in pts with advanced solid tumors. Methods: This ongoing study (N=160) includes a dose escalation phase (Part 1) using a 3 + 3 design followed by an expansion phase (Part 2). In Part 1 (N=60), successive pt cohorts with advanced solid tumors are being treated with escalating doses of rIL-21 (10, 30, 50, 75, or 100 µg/kg IV) on two distinct schedules (Arms A and B) in combination with fixed-dose nivolumab (3 mg/kg q 2 weeks) in 6 week cycles. Arm A administers rIL-21 on a weekly schedule, given on day 1 in weeks 1–4 of the 6 week cycle. Arm B administers rIL-21 at 3x per week during weeks 1 and 3 of the 6 week cycle. In Part 2, pts with renal cell carcinoma (N=50) or non-small cell lung carcinoma (N=50) will each be randomized to treatment at the maximum tolerated dose (MTD) or maximum administered dose, if no MTD is determined, for Arm A or Arm B. Therapy for pts who are stable or responding in Parts 1 and 2 may be continued for up to 2 years or until treatment discontinuation criteria are met. Primary objectives are to evaluate the safety of rIL-21 + nivolumab, and to define the MTD of the 2 schedules. Secondary and exploratory objectives include a preliminary assessment of the antitumor activity, pharmacokinetics, immunoregulatory activity (peripheral blood, tumor) and immunogenicity of this combination. Clinical trial information: NCT01629758.

Agonist Antibodies to TNFR Molecules That Costimulate T and NK Cells

Therapy for cancer can be achieved by artificially stimulating antitumor T and natural killer (NK) lymphocytes with agonist monoclonal antibodies (mAb). T and NK cells express several members of the TNF receptor (TNFR) family specialized in delivering a costimulatory signal on their surface. Engagement of these receptors is typically associated with proliferation, elevated effector functions, resistance to apoptosis, and differentiation into memory cells. These receptors lack any intrinsic enzymatic activity and their signal transduction relies on associations with TNFR-associated factor (TRAF) adaptor proteins. Stimulation of CD137 (4-1BB), CD134 (OX40), and glucocorticoid-induced TNFR (GITR; CD357) promotes impressive tumor-rejecting immunity in a variety of murine tumor models. The mechanisms of action depend on a complex interplay of CTL, T-helper cells, regulatory T cells, dendritic cells, and vascular endothelium in tumors. Agonist mAbs specific for CD137 have shown signs of objective clinical activity in patients with metastatic melanoma, whereas anti-OX40 and anti-GITR mAbs have entered clinical trials. Preclinical evidence suggests that engaging TNFR members would be particularly active with conventional cancer therapies and additional immunotherapeutic approaches. Indeed, T-cell responses elicited to tumor antigens by means of immunogenic tumor cell death are amplified by these immunostimulatory agonist mAbs. Furthermore, anti-CD137 mAbs have been shown to enhance NK-mediated cytotoxicity elicited by rituximab and trastuzumab. Combinations with other immunomodulatory mAb that block T-cell checkpoint blockade receptors such as CTLA-4 and PD-1 are also promising.