Efficacy of nivolumab and ipilimumab in patients with malignant pleural mesothelioma is related to a subtype of effector memory cytotoxic T cells: Translational evidence from two clinical trials.

Combined immune checkpoint inhibitor (ICI) treatment targeting PD-1 and CTLA-4 was suggested to yield clinical benefit over chemotherapy in malignant pleural mesothelioma (MPM), whereas aPD-1 monotherapy failed to provide benefit in phase-III trials. Success of ICI depends on the presence and activation of tumor-specific T cells. Therefore, we investigated whether T-cell characteristics are underlying clinical efficacy of ICI treatment in MPM. Comprehensive immune cell profiling was performed on screening and on treatment peripheral blood samples of mesothelioma patients treated with nivolumab (aPD-1) monotherapy (NCT02497508), or a combination of nivolumab and ipilimumab (aCTLA-4) (NCT03048474). aPD-1/aCTLA-4 combination treatment induced a profound increase in proliferation and activation of T cells, which was not observed upon aPD-1 monotherapy. Moreover, patients that responded to combination treatment had low frequencies of naive CD8 T cells and high frequencies of effector memory CD8 T cells that re-expressed RA (TEMRA) at screening. The frequency of Granzyme-B and Interferon-γ producing TEMRAs was also higher in responding patients. High proportions of TEMRAs and cytokine production by TEMRAs before treatment, was associated with a better clinical outcome. TEMRAs, which likely comprise tumor-specific T cells, tend to require blockage of both aPD-1 and aCTLA-4 to be reactivated. In conclusion, peripheral blood TEMRAs can play a key role in explaining and predicting clinical benefit upon aPD-1/aCTLA-4 combination treatment. Bristol-Myers Squibb sponsored NivoMes and INITIATE clinical trials and provided study drugs. No external funding was applicable for the flow cytometric analyses of peripheral blood samples described in this manuscript.

Mankor JM ，Disselhorst MJ ，Poncin M ，Baas P ，Aerts JGJV ，Vroman H ... -  《EBioMedicine》

Ipilimumab and nivolumab in the treatment of recurrent malignant pleural mesothelioma (INITIATE): results of a prospective, single-arm, phase 2 trial.

Single-drug checkpoint inhibition has shown efficacy in patients with recurrent malignant pleural mesothelioma. Here, we assessed the safety and efficacy of the combination of nivolumab, an anti-programmed cell death 1 antibody, plus ipilimumab, an anti-cytotoxic T-lymphocyte protein 4 antibody, in patients with previously treated and relapsed malignant pleural mesothelioma. INITIATE was a prospective single-centre, single arm, phase 2 trial. Patients with malignant pleural mesothelioma who progressed after at least one line of platinum-containing chemotherapy were enrolled. Key eligibility criteria were measurable disease according to the modified Response Evaluation Criteria in Solid Tumours for mesotheliomas, Eastern Cooperative Oncology Group performance status 0 or 1, and adequate organ function. Patients received intravenous nivolumab (240 mg every 2 weeks) plus intravenous ipilimumab (1 mg/kg every 6 weeks up to four times). Treatment was continued for up to 2 years or until confirmed progression or unacceptable toxicity. The primary endpoint was disease control at 12 weeks. All patients who received at least one dose of therapy were included in safety analysis and all patients who received one dose of therapy and at least one radiological assessment were included in the primary analysis. This trial is registered at ClinicalTrials.gov, number NCT03048474. Between Oct 5, 2016, and Aug 3, 2017, 38 patients were enrolled in the study, of which two patients were excluded because they were not eligible for a biopsy. Of 36 eligible patients, one deteriorated before the start of the study so was not included in any analyses and one withdrew consent after one treatment cycle before radiological assessment so was included in the safety population only. 34 patients were evaluable for response assessment at 12 weeks. Of these, ten (29%) patients had a partial response and 13 (38%) patients had stable disease; thus, disease control was achieved by 23 (68%, 95% CI 50-83) of 34 patients. Treatment-related adverse events were reported in 33 (94%) patients. The most common adverse events were infusion-related reactions, skin disorders, and fatigue. Grade 3 treatment-related adverse events were reported in 12 (34%) of 35 patients. In this single-centre phase 2 trial, the combination of nivolumab plus ipilimumab showed marked efficacy in patients with recurrent malignant pleural mesothelioma. The safety profile was consistent with known data on the combination regimen. Our results warrant further investigation of this combination in a phase 3 trial. Bristol-Myers Squibb.

Disselhorst MJ ，Quispel-Janssen J ，Lalezari F ，Monkhorst K ，de Vries JF ，van der Noort V ，Harms E ，Burgers S ，Baas P ... -  《-》

Nivolumab or nivolumab plus ipilimumab in patients with relapsed malignant pleural mesothelioma (IFCT-1501 MAPS2): a multicentre, open-label, randomised, non-comparative, phase 2 trial.

There is no recommended therapy for malignant pleural mesothelioma that has progressed after first-line pemetrexed and platinum-based chemotherapy. Disease control has been less than 30% in all previous studies of second-line drugs. Preliminary results have suggested that anti-programmed cell death 1 (PD-1) monoclonal antibody could be efficacious in these patients. We thus aimed to prospectively assess the anti-PD-1 monoclonal antibody alone or in combination with anti-cytotoxic T-lymphocyte protein 4 (CTLA-4) antibody in patients with malignant pleural mesothelioma. This multicentre randomised, non-comparative, open-label, phase 2 trial was done at 21 hospitals in France. Eligible patients were aged 18 years or older with an Eastern Cooperative Oncology Group performance status of 0-1, histologically proven malignant pleural mesothelioma progressing after first-line or second-line pemetrexed and platinum-based treatments, measurable disease by CT, and life expectancy greater than 12 weeks. Patients were randomly allocated (1:1) to receive intravenous nivolumab (3 mg/kg bodyweight) every 2 weeks, or intravenous nivolumab (3 mg/kg every 2 weeks) plus intravenous ipilimumab (1 mg/kg every 6 weeks), given until progression or unacceptable toxicity. Central randomisation was stratified by histology (epithelioid vs non-epithelioid), treatment line (second line vs third line), and chemosensitivity to previous treatment (progression ≥3 months vs <3 months after pemetrexed treatment) and used a minimisation method with a 0·8 random factor. The primary outcome was the proportion of patients who achieved 12-week disease control, assessed by masked independent central review; the primary endpoint would be met if disease control was achieved in at least 40% of patients. The primary endpoint was assessed in the first 108 eligible patients. Efficacy analyses were also done in the intention-to-treat population and safety analyses were done in all patients who received at least one dose of their assigned treatment. This trial is registered at ClinicalTrials.gov, number NCT02716272. Between March 24 and August 25, 2016, 125 eligible patients were recruited and assigned to either nivolumab (n=63) or nivolumab plus ipilimumab (n=62). In the first 108 eligible patients, 12-week disease control was achieved by 24 (44%; 95% CI 31-58) of 54 patients in the nivolumab group and 27 (50%; 37-63) of 54 patients in the nivolumab plus ipilimumab group. In the intention-to-treat population, 12-week disease control was achieved by 25 (40%; 28-52) of 63 patients in the nivolumab group and 32 (52%; 39-64) of 62 patients in the combination group. Nine (14%) of 63 patients in the nivolumab group and 16 (26%) of 61 patients in the combination group had grade 3-4 toxicities. The most frequent grade 3 adverse events were asthenia (one [2%] in the nivolumab group vs three [5%] in the combination group), asymptomatic increase in aspartate aminotransferase or alanine aminotransferase (none vs four [7%] of each), and asymptomatic lipase increase (two [3%] vs one [2%]). No patients had toxicities leading to death in the nivolumab group, whereas three (5%) of 62 in the combination group did (one fulminant hepatitis, one encephalitis, and one acute kidney failure). Anti-PD-1 nivolumab monotherapy or nivolumab plus anti-CTLA-4 ipilimumab combination therapy both showed promising activity in relapsed patients with malignant pleural mesothelioma, without unexpected toxicity. These regimens require confirmation in larger clinical trials. French Cooperative Thoracic Intergroup.

Scherpereel A ，Mazieres J ，Greillier L ，Lantuejoul S ，Dô P ，Bylicki O ，Monnet I ，Corre R ，Audigier-Valette C ，Locatelli-Sanchez M ，Molinier O ，Guisier F ，Urban T ，Ligeza-Poisson C ，Planchard D ，Amour E ，Morin F ，Moro-Sibilot D ，Zalcman G ，French Cooperative Thoracic Intergroup ... -  《-》

Immune cells in mesothelioma microenvironment simplistic marker of response to nivolumab plus ipilimumab?

Malignant pleural mesothelioma (MPM) is a malignant disease of the pleura which recently can be treated with immune checkpoint inhibitors (ICI). To optimize this treatment, a better understanding of the tumor micro environment is needed. We investigated subgroups of immune cells in subsequent tumor biopsies of patients treated with ICI. Biopsies from MPM patients included in two clinical ICI trials (nivolumab alone and an ipilimumab/nivolumab combination) were examined. At baseline and after 6 weeks of treatment, pleural biopsies were taken to examine the tumor microenvironment (CD20+, CD4+, CD8+, FoxP3+ and PD-1+ ). Cell density was defined as the number of marker positive cells per mm2. Radiological responses were evaluated as partial response, stable disease or progressive disease according to modified RECIST criteria. Thirty-four and 36 patients were included in the nivolumab and ipiliumumab/nivolumab trial respectively. In the nivolumab trial, no significant differences in cell densities were seen in baseline biopsies of patients with partial response versus progressive disease. In contrast, in the ipilimumab/nivolumab trial, a higher cell density of CD4+, CD8+, FoxP3+ and PD-1+ cells at baseline was significantly correlated with partial responses. On-treatment biopsies of both trials did not show significant changes when compared to baseline biopsies. Biopsies from patients responding to nivolumab plus ipilimumab treatment show a significant higher cell density of CD4+, CD8+, FoxP3+ and PD-1+ cells, without a change after 6 weeks of treatment. This observation is a first step in exploring the tumor microenvironment as predictor of response in ICI treatment in MPM.

Disselhorst MJ ，Lubeck Y ，van der Noort V ，Quispel-Janssen J ，Seignette IM ，Sanders J ，Peters D ，Hooijberg E ，Baas P ... -  《-》

Dynamics and survival associations of T cell receptor clusters in patients with pleural mesothelioma treated with immunotherapy.

Immune checkpoint inhibitors (ICIs) are now a first-line treatment option for patients with pleural mesothelioma with the recent approval of ipilimumab and nivolumab. Mesothelioma has a low tumor mutation burden and no robust predictors of survival with ICI. Since ICIs enable adaptive antitumor immune responses, we investigated T-cell receptor (TCR) associations with survival in participants from two clinical trials treated with ICI. We included patients with pleural mesothelioma who were treated with nivolumab (NivoMes, NCT02497508) or nivolumab and ipilimumab (INITIATE, NCT03048474) after first-line therapy. TCR sequencing was performed with the ImmunoSEQ assay in 49 and 39 pretreatment and post-treatment patient peripheral blood mononuclear cell (PBMC) samples. These data were integrated with TCR sequences found in bulk RNAseq data by TRUST4 program in 45 and 35 pretreatment and post-treatment tumor biopsy samples and TCR sequences from over 600 healthy controls. The TCR sequences were clustered into groups of shared antigen specificity using GIANA. Associations of TCR clusters with overall survival were determined by cox proportional hazard analysis. We identified 4.2 million and 12 thousand complementarity-determining region 3 (CDR3) sequences from PBMCs and tumors, respectively, in patients treated with ICI. These CDR3 sequences were integrated with 2.1 million publically available CDR3 sequences from healthy controls and clustered. ICI-enhanced T-cell infiltration and expanded T cell diversity in tumors. Cases with TCR clones in the top tertile in the pretreatment tissue or in circulation had significantly better survival than the bottom two tertiles (p<0.04). Furthermore, a high number of shared TCR clones between pretreatment tissue and in circulation was associated with improved survival (p=0.01). To potentially select antitumor clusters, we filtered for clusters that were (1) not found in healthy controls, (2) recurrent in multiple patients with mesothelioma, and (3) more prevalent in post-treatment than pretreatment samples. The detection of two-specific TCR clusters provided significant survival benefit compared with detection of 1 cluster (HR<0.001, p=0.026) or the detection of no TCR clusters (HR=0.10, p=0.002). These two clusters were not found in bulk tissue RNA-seq data and have not been reported in public CDR3 databases. We identified two unique TCR clusters that were associated with survival on treatment with ICI in patients with pleural mesothelioma. These clusters may enable approaches for antigen discovery and inform future targets for design of adoptive T cell therapies.

Desai AP ，Kosari F ，Disselhorst M ，Yin J ，Agahi A ，Peikert T ，Udell J ，Johnson SH ，Smadbeck J ，Murphy S ，Karagouga G ，McCune A ，Schaefer-Klein J ，Borad MJ ，Cheville J ，Vasmatzis G ，Baas P ，Mansfield A ... -  《-》