In the last few years, immunotherapy has become an important cancer treatment modality, and although the principles of immunotherapy have evolved over many decades, the FDA approvals of sipuleucel-T ...and ipilimumab began a new wave in immuno-oncology. Despite the current enthusiasm, it is unlikely that any of the immunotherapeutics alone can dramatically change prostate cancer outcomes, but combination strategies are more promising and provide a reason for optimism. Several completed and ongoing studies have shown that the combination of cancer vaccines or checkpoint inhibitors with different immunotherapeutic agents, hormonal therapy (enzalutamide), radiotherapy (radium 223), DNA-damaging agents (olaparib), or chemotherapy (docetaxel) can enhance immune responses and induce more dramatic, long-lasting clinical responses without significant toxicity. The goal of prostate cancer immunotherapy does not have to be complete eradication of advanced disease but rather the return to an immunologic equilibrium with an indolent disease state. In addition to determining the optimal combination of treatment regimens, efforts are also ongoing to discover biomarkers of immune response. With such concerted efforts, the future of immunotherapy in prostate cancer looks brighter than ever.
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Immunosuppressive entities in the tumor microenvironment (TME) remain a major impediment to immunotherapeutic approaches for a majority of patients with cancer. While the immunosuppressive role of ...transforming growth factor-β (TGF-β) in the TME is well known, clinical studies to date with anti-TGF-β agents have led to limited success. The bifunctional agent bintrafusp alfa (previously designated M7824) has been developed in an attempt to address this issue. Bintrafusp alfa consists of an IgG1 targeting programmed death ligand 1 (PD-L1) moiety fused via peptide linkers to the extracellular domain of two TGF-β receptor II molecules designed to ‘trap’ TGF-β in the TME. This agent is able to bring the TGF-β trap to the TME via its anti-PD-L1 component, thus simultaneously attacking both the immunosuppressive PD-L1 and TGF-β entities. A number of preclinical studies have shown bintrafusp alfa capable of (1) preventing or reverting TGF-β-induced epithelial-mesenchymal transition in human carcinoma cells; this alteration in tumor cell plasticity was shown to render human tumor cells more susceptible to immune-mediated attack as well as to several chemotherapeutic agents; (2) altering the phenotype of natural killer and T cells, thus enhancing their cytolytic ability against tumor cells; (3) mediating enhanced lysis of human tumor cells via the antibody-dependent cell-mediated cytotoxicity mechanism; (4) reducing the suppressive activity of Treg cells; (5) mediating antitumor activity in numerous preclinical models and (6) enhancing antitumor activity in combination with radiation, chemotherapy and several other immunotherapeutic agents. A phase I clinical trial demonstrated a safety profile similar to other programmed cell death protein 1 (PD-1)/PD-L1 checkpoint inhibitors, with objective and durable clinical responses. We summarize here preclinical and emerging clinical data in the use of this bispecific and potentially multifunctional agent.
Immunotherapy is an important breakthrough in cancer. US Food and Drug Administration-approved immunotherapies for cancer treatment (including, but not limited to, sipuleucel-T, ipilimumab, ...nivolumab, pembrolizumab, and atezolizumab) substantially improve overall survival across multiple malignancies. One mechanism of action of these treatments is to induce an immune response against antigen-bearing tumor cells; the resultant cell death releases secondary (nontargeted) tumor antigens. Secondary antigens prime subsequent immune responses (antigen spread). Immunotherapy-induced antigen spread has been shown in clinical studies. For example, in metastatic castration-resistant prostate cancer patients, sipuleucel-T induced early immune responses to the immunizing antigen (PA2024) and/or the target antigen (prostatic acid phosphatase). Thereafter, most patients developed increased antibody responses to numerous secondary proteins, several of which are expressed in prostate cancer with functional relevance in cancer. The ipilimumab-induced antibody profile in melanoma patients shows that antigen spread also occurs with immune checkpoint blockade. In contrast to chemotherapy, immunotherapy often does not result in short-term changes in conventional disease progression end points (eg, progression-free survival, tumor size), which may be explained, in part, by the time taken for antigen spread to occur. Thus, immune-related response criteria need to be identified to better monitor the effectiveness of immunotherapy. As immunotherapy antitumor effects take time to evolve, immunotherapy in patients with less advanced cancer may have greater clinical benefit vs those with more advanced disease. This concept is supported by prostate cancer clinical studies with sipuleucel-T, PSA-TRICOM, and ipilimumab. We discuss antigen spread with cancer immunotherapy and its implications for clinical outcomes.
The approval of anti-programmed death ligand 1 (PD-L1) and anti-programmed death 1 agents has expanded treatment options for patients with locally advanced or metastatic urothelial carcinoma. ...Avelumab, a human monoclonal anti-PD-L1 antibody, has shown promising antitumour activity and safety in this disease. We aimed to assess the safety profile in patients (both post-platinum therapy and cisplatin-naive) treated with avelumab and to assess antitumour activity of this drug in post-platinum patients.
In this pooled analysis of two cohorts from the phase 1 dose-expansion JAVELIN Solid Tumor study, patients aged 18 years and older with histologically or cytologically confirmed locally advanced or metastatic urothelial carcinoma that had progressed after at least one previous platinum-based chemotherapy were enrolled from 80 cancer treatment centres or hospitals in the USA, Europe, and Asia. Eligible patients had adequate end-organ function, an Eastern Cooperative Oncology Group performance status of 0 or 1, life expectancy of at least 3 months, and at least one measurable lesion. Cisplatin-ineligible patients who might have been previously treated in the perioperative setting, including platinum-naive patients, were also eligible. Patients unselected for PD-L1 expression received avelumab (10 mg/kg, 1 h intravenous infusion) every 2 weeks until confirmed disease progression, unacceptable toxicity, or other criterion for withdrawal. The primary endpoint for this efficacy expansion cohort was confirmed best overall response (according to RECIST version 1.1), adjudicated by independent review. Safety analysis was done in all patients who received at least one dose of avelumab. Antitumour activity was assessed in post-platinum patients who received at least one dose of avelumab. This trial is registered with ClinicalTrials.gov, number NCT01772004; enrolment in this cohort of patients with metastatic urothelial carcinoma is closed and the trial is ongoing.
Between Sept 3, 2014, and March 15, 2016, 329 patients with advanced metastatic urothelial carcinoma were screened for enrolment into this study; 249 patients were eligible and received treatment with avelumab for a median of 12 weeks (IQR 6·0–19·7) and followed up for a median of 9·9 months (4·3–12·1). Safety and antitumour activity were evaluated at data cutoff on June 9, 2016. In 161 post-platinum patients with at least 6 months of follow-up, a best overall response of complete or partial response was recorded in 27 patients (17%; 95% CI 11–24), including nine (6%) complete responses and 18 (11%) partial responses. The most frequent treatment-related adverse events (any grade in ≥10% patients) were infusion-related reaction (73 29%; all grade 1–2) and fatigue (40 16%). Grade 3 or worse treatment-related adverse events occurred in 21 (8%) of 249 patients, the most common of which were fatigue (four 2%), and asthenia, elevated lipase, hypophosphataemia, and pneumonitis in two (1%) patients each. 19 (8%) of 249 patients had a serious adverse event related to treatment with avelumab, and one treatment-related death occurred (pneumonitis).
Avelumab showed antitumour activity in the treatment of patients with platinum-refractory metastatic urothelial carcinoma; a manageable safety profile was reported in all avelumab-treated patients. These data provide the rationale for therapeutic use of avelumab in metastatic urothelial carcinoma and it has received accelerated US FDA approval in this setting on this basis.
Merck KGaA, and Pfizer Inc.
Several anti-PD-1/PD-L1 monoclonal antibodies (mAb) are currently providing evidence of clinical benefit in subsets of cancer patients. The mode of action of these mAbs is to inhibit PD-1 on immune ...cells interacting with PD-L1 on tumor cells. These mAbs are either designed or engineered to eliminate antibody-dependent cell-mediated cytotoxicity (ADCC), which, however, has been implicated as an important mechanism in several highly effective mAb-mediated cancer therapies. A fully human anti-PD-L1 mAb would potentially be able to block PD-1/PD-L1 interactions and also mediate the ADCC lysis of tumor cells. MSB0010718C (designated avelumab) is a fully human IgG1 anti-PD-L1 mAb. The studies reported here demonstrate (i) the ability of avelumab to lyse a range of human tumor cells in the presence of PBMC or NK effectors; (ii) IFNγ can enhance tumor cell PD-L1 expression and, in some cases, enhance ADCC tumor cell lysis; (iii) purified NK cells are potent effectors for avelumab; (iv) similar levels of avelumab-mediated ADCC lysis of tumor cells are seen using purified NK as effectors from either healthy donors or cancer patients; (v) very low levels of avelumab-mediated lysis are seen using whole PBMCs as targets; this finding complements results seen in analyses of PBMC subsets of patients receiving avelumab; and (vi) the addition of IL12 to NK cells greatly enhances avelumab-mediated ADCC. These studies thus provide an additional mode of action for an anti-PD-L1 mAb and support the rationale for further studies to enhance avelumab-mediated ADCC activity.
Even though the number of agents that inhibit TGFβ being tested in patients with cancer has grown substantially, clinical benefit from TGFβ inhibition has not yet been achieved. The myriad mechanisms ...in which TGFβ is protumorigenic may be a key obstacle to its effective deployment; cancer cells frequently employ TGFβ-regulated programs that engender plasticity, enable a permissive tumor microenvironment, and profoundly suppress immune recognition, which is the target of most current early-phase trials of TGFβ inhibitors. Here we discuss the implications of a less well-recognized aspect of TGFβ biology regulating DNA repair that mediates responses to radiation and chemotherapy. In cancers that are TGFβ signaling competent, TGFβ promotes effective DNA repair and suppresses error-prone repair, thus conferring resistance to genotoxic therapies and limiting tumor control. Cancers in which TGFβ signaling is intrinsically compromised are more responsive to standard genotoxic therapy. Recognition that TGFβ is a key moderator of both DNA repair and immunosuppression might be used to synergize combinations of genotoxic therapy and immunotherapy to benefit patients with cancer.
Summary Background Therapeutic cancer vaccines have shown activity in metastatic castration-resistant prostate cancer (mCRPC), and methods are being assessed to enhance their efficacy. Ipilimumab is ...an antagonistic monoclonal antibody that binds cytotoxic T-lymphocyte-associated protein 4, an immunomodulatory molecule expressed by activated T cells, and to CD80 on antigen-presenting cells. We aimed to assess the safety and tolerability of ipilimumab in combination with a poxviral-based vaccine targeting prostate-specific antigen (PSA) and containing transgenes for T-cell co-stimulatory molecule expression, including CD80. Methods We did a phase 1 dose-escalation trial, with a subsequent expansion phase, to assess the safety and tolerability of escalating doses of ipilimumab in combination with a fixed dose of the PSA-Tricom vaccine. Patients with mCRPC received 2×108 plaque-forming units of recombinant vaccinia PSA-Tricom subcutaneously on day 1 of cycle 1, with subsequent monthly boosts of 1×109 plaque-forming units, starting on day 15. Intravenous ipilimumab was given monthly starting at day 15, in doses of 1, 3, 5, and 10 mg/kg. Our primary goal was to assess the safety of the combination. This study is registered with ClinicalTrials.gov , number NCT00113984. Findings We completed enrolment with 30 patients (24 of whom had not been previously treated with chemotherapy) and we did not identify any dose-limiting toxic effects. Grade 1 and 2 vaccination-site reactions were the most common toxic effects: three of 30 patients had grade 1 reactions and 26 had grade 2 reactions. 21 patients had grade 2 or greater immune-related adverse events. Grade 3 or 4 immune-related adverse events included diarrhoea or colitis in four patients and grade 3 rash (two patients), grade 3 raised aminotransferases (two patients), grade 3 endocrine immune-related adverse events (two patients), and grade 4 neutropenia (one patient). Only one of the six patients previously treated with chemotherapy had a PSA decline from baseline. Of the 24 patients who were chemotherapy-naive, 14 (58%) had PSA declines from baseline, of which six were greater than 50%. Interpretation The use of a vaccine targeting PSA that also enhances co-stimulation of the immune system did not seem to exacerbate the immune-related adverse events associated with ipilimumab. Randomised trials are needed to further assess clinical outcomes of the combination of ipilimumab and vaccine in mCRPC. Funding US National Institutes of Health.
Summary Background Avelumab (MSB0010718C) is a human IgG1 monoclonal antibody that binds to PD-L1, inhibiting its binding to PD-1, which inactivates T cells. We aimed to establish the safety and ...pharmacokinetics of avelumab in patients with solid tumours while assessing biological correlatives for future development. Methods This open-label, single-centre, phase 1a, dose-escalation trial (part of the JAVELIN Solid Tumor trial) assessed four doses of avelumab (1 mg/kg, 3 mg/kg, 10 mg/kg, and 20 mg/kg), with dose-level cohort expansions to provide additional safety, pharmacokinetics, and target occupancy data. This study used a standard 3 + 3 cohort design and assigned patients sequentially at trial entry according to the 3 + 3 dose-escalation algorithm and depending on the number of dose-limiting toxicities during the first 3-week assessment period (the primary endpoint). Patient eligibility criteria included age 18 years or older, Eastern Cooperative Oncology Group performance status 0–1, metastatic or locally advanced previously treated solid tumours, and adequate end-organ function. Avelumab was given as a 1-h intravenous infusion every 2 weeks. Patients in the dose-limiting toxicity analysis set were assessed for the primary endpoint of dose-limiting toxicity, and all patients enrolled in the dose-escalation part were assessed for the secondary endpoints of safety (treatment-emergent and treatment-related adverse events according to National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0), pharmacokinetic and pharmacodynamic profiles (immunological effects), best overall response by Response Evaluation Criteria, and antidrug antibody formation. The population for the pharmacokinetic analysis included a subset of patients with rich pharmacokinetic samples from two selected disease-specific expansion cohorts at the same study site who had serum samples obtained at multiple early timepoints. This trial is registered with ClinicalTrials.gov , number NCT01772004 . Patient recruitment to the dose-escalation part reported here is closed. Findings Between Jan 31, 2013, and Oct 8, 2014, 53 patients were enrolled (four patients at 1 mg/kg, 13 at 3 mg/kg, 15 at 10 mg/kg, and 21 at 20 mg/kg). 18 patients were analysed in the dose-limiting toxicity analysis set: three at dose level 1 (1 mg/kg), three at dose level 2 (3 mg/kg), six at dose level 3 (10 mg/kg), and six at dose level 4 (20 mg/kg). Only one dose-limiting toxicity occurred, at the 20 mg/kg dose, and thus the maximum tolerated dose was not reached. In all 53 enrolled patients (the safety analysis set), common treatment-related adverse events (occurring in >10% of patients) included fatigue (21 patients 40%), influenza-like symptoms (11 21%), fever (8 15%), and chills (6 11%). Grade 3–4 treatment-related adverse events occurred in nine (17%) of 53 patients, with autoimmune disorder (n=3), increased blood creatine phosphokinase (n=2), and increased aspartate aminotransferase (n=2) each occurring in more than one patient (autoimmune disorder in two patients at 10 mg/kg and one patient at 20 mg/kg, increased blood creatine phosphokinase in two patients at 20 mg/kg, and increased aspartate aminotransferase in one patient at 1 mg/kg, and one patient at 10 mg/kg). Six (11%) of 53 patients had a serious treatment-related adverse event: autoimmune disorder (two 13%), lower abdominal pain (one 7%), fatigue (one 7%), and influenza-like illness (one 7%) in three patients treated at 10 mg/kg dose level, and autoimmune disorder (one 5%), increased amylase (one 5%), myositis (one 5%), and dysphonia (one 5%) in three patients who received the 20 mg/kg dose. We recorded some evidence of clinical activity in various solid tumours, with partial confirmed or unconfirmed responses in four (8%) of 53 patients; 30 (57%) additional patients had stable disease. Pharmacokinetic analysis (n=86) showed a dose-proportional exposure between doses of 3 mg/kg and 20 mg/kg and a half-life of 95–99 h (3·9–4·1 days) at the 10 mg/kg and 20 mg/kg doses. Target occupancy was greater than 90% at doses of 3 mg/kg and 10 mg/kg. Antidrug antibodies were detected in two (4%) of 53 patients. No substantial differences were found in absolute lymphocyte count or multiple immune cell subsets, including those expressing PD-L1, after treatment with avelumab. 31 (58%) of 53 patients in the overall safety population died; no deaths were related to treatment on study. Interpretation Avelumab has an acceptable toxicity profile up to 20 mg/kg and the maximum tolerated dose was not reached. Based on pharmacokinetics, target occupancy, and immunological analysis, we chose 10 mg/kg every 2 weeks as the dose for further development and phase 3 trials are ongoing. Funding National Cancer Institute and Merck KGaA.
Therapeutic options for metastatic prostate cancer patients are currently limited. In this issue of Cancer Cell, Kfoury et al. characterized the tumor and immune compartments of prostate cancer bone ...metastasis, revealing a mechanism of immunosuppression that involves infiltration with M2 macrophages and T cell exhaustion mediated by the CCL20-CCR6 axis.
Therapeutic options for metastatic prostate cancer patients are currently limited. In this issue of Cancer Cell, Kfoury et al. characterized the tumor and immune compartments of prostate cancer bone metastasis, revealing a mechanism of immunosuppression that involves infiltration with M2 macrophages and T cell exhaustion mediated by the CCL20-CCR6 axis.
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