Pembrolizumab plus lenvatinib in second-line and third-line patients with pleural mesothelioma (PEMMELA): a single-arm phase 2 study.

BACKGROUND: The combination of pembrolizumab, an anti-PD-1 antibody, and lenvatinib, an antiangiogenic multikinase inhibitor, shows synergistic activity in preclinical and clinical studies in solid tumours. We assessed the clinical activity of this combination therapy in patients with pleural mesothelioma who progressed after platinum-pemetrexed chemotherapy. METHODS: In this single-arm, single-centre, phase 2 study, done at the Netherlands Cancer Institute in Amsterdam, The Netherlands, eligible patients (aged ≥18 years) with pleural mesothelioma with an Eastern Cooperative Oncology Group performance status of 0-1, progression after chemotherapy (no previous immunotherapy), and measurable disease according to the modified Response Evaluation Criteria In Solid Tumours (mRECIST) for mesothelioma version 1.1. Patients received 200 mg intravenous pembrolizumab once every 3 weeks plus 20 mg oral lenvatinib once per day for up to 2 years or until disease progression, development of unacceptable toxicity, or withdrawal of consent. The primary endpoint was objective response rate identified by a local investigator according to mRECIST version 1.1. This trial is registered with ClinicalTrials.gov, NCT04287829, and is recruiting for the second cohort. FINDINGS: Between March 5, 2021, and Jan 31, 2022, 42 patients were screened, of whom 38 were included in the primary endpoint and safety analyses (median age 71 years [IQR 65-75], 33 [87%] male and five [13%] female) . At data cutoff (Jan 31, 2023), with a median follow-up of 17·7 months (IQR 13·8-19·4), 22 (58%; 95% CI 41-74) of 38 patients had an objective response. The independent review showed an objective response in 17 (45%; 95% CI 29-62) of 38 patients. Serious treatment-related adverse events occurred in ten (26%) patients, including one treatment-related death due to myocardial infarction. The most common treatment-related grade 3 or worse adverse events were hypertension (eight patients [21%]) and anorexia and lymphopenia (both four patients [11%]). In 29 (76%) of 38 patients, at least one dose reduction or discontinuation of lenvatinib was required. INTERPRETATION: Pembrolizumab plus lenvatinib showed promising anti-tumour activity in patients with pleural mesothelioma with considerable toxicity, similar to that in previous studies. Available evidence from the literature suggests a high starting dose of lenvatinib for optimal anti-tumour activity. This, however, demands a high standard of supportive care. The combination therapy of pembrolizumab and lenvatinib warrants further investigation in pleural mesothelioma. FUNDING: Merck Sharp & Dohme.

Effect of Pembrolizumab After Stereotactic Body Radiotherapy vs Pembrolizumab Alone on Tumor Response in Patients With Advanced Non-Small Cell Lung Cancer: Results of the PEMBRO-RT Phase 2 Randomized Clinical Trial.

IMPORTANCE: Many patients with advanced non-small cell lung cancer (NSCLC) receiving immunotherapy show primary resistance. High-dose radiotherapy can lead to increased tumor antigen release, improved antigen presentation, and T-cell infiltration. This radiotherapy may enhance the effects of checkpoint inhibition. OBJECTIVE: To assess whether stereotactic body radiotherapy on a single tumor site preceding pembrolizumab treatment enhances tumor response in patients with metastatic NSCLC. DESIGN, SETTING, AND PARTICIPANTS: Multicenter, randomized phase 2 study (PEMBRO-RT) of 92 patients with advanced NSCLC enrolled between July 1, 2015, and March 31, 2018, regardless of programmed death-ligand 1 (PD-L1) status. Data analysis was of the intention-to-treat population. INTERVENTIONS: Pembrolizumab (200 mg/kg every 3 weeks) either alone (control arm) or after radiotherapy (3 doses of 8 Gy) (experimental arm) to a single tumor site until confirmed radiographic progression, unacceptable toxic effects, investigator decision, patient withdrawal of consent, or a maximum of 24 months. MAIN OUTCOMES AND MEASURES: Improvement in overall response rate (ORR) at 12 weeks from 20% in the control arm to 50% in the experimental arm with P < .10. RESULTS: Of the 92 patients enrolled, 76 were randomized to the control arm (n = 40) or the experimental arm (n = 36). Of those, the median age was 62 years (range, 35-78 years), and 44 (58%) were men. The ORR at 12 weeks was 18% in the control arm vs 36% in the experimental arm (P = .07). Median progression-free survival was 1.9 months (95% CI, 1.7-6.9 months) vs 6.6 months (95% CI, 4.0-14.6 months) (hazard ratio, 0.71; 95% CI, 0.42-1.18; P = .19), and median overall survival was 7.6 months (95% CI, 6.0-13.9 months) vs 15.9 months (95% CI, 7.1 months to not reached) (hazard ratio, 0.66; 95% CI, 0.37-1.18; P = .16). Subgroup analyses showed the largest benefit from the addition of radiotherapy in patients with PD-L1-negative tumors. No increase in treatment-related toxic effects was observed in the experimental arm. CONCLUSIONS AND RELEVANCE: Stereotactic body radiotherapy prior to pembrolizumab was well tolerated. Although a doubling of ORR was observed, the results did not meet the study's prespecified end point criteria for meaningful clinical benefit. Positive results were largely influenced by the PD-L1-negative subgroup, which had significantly improved progression-free survival and overall survival. These results suggest that a larger trial is necessary to determine whether radiotherapy may activate noninflamed NSCLC toward a more inflamed tumor microenvironment. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02492568.

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

BACKGROUND: 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. METHODS: 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. FINDINGS: 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. INTERPRETATION: 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. FUNDING: Bristol-Myers Squibb.

Programmed Death 1 Blockade With Nivolumab in Patients With Recurrent Malignant Pleural Mesothelioma.

INTRODUCTION: Malignant pleural mesothelioma (MPM) has limited treatment options and a poor outcome. Programmed death 1/programmed death ligand 1 (PD-L1) checkpoint inhibitors have proven efficacious in several cancer types. Nivolumab is a fully humanized monoclonal antibody against programmed death 1 with a favorable toxicity profile. In MPM, the immune system is considered to play an important role. We therefore tested nivolumab in recurrent MPM. METHODS: In this single-center trial, patients with MPM received nivolumab 3 mg/kg intravenously every 2 weeks. Primary endpoint was the disease control rate at 12 weeks. Pre- and on-treatment biopsy specimens were obtained to analyze biomarkers for response. RESULTS: Of the 34 patients included, 8 patients (24%) had a partial response at 12 weeks and another 8 had stable disease resulting in a disease control rate at 12 weeks of 47%. One reached a partial response at 18 weeks. In 4 patients with stable disease, the tumor remained stable for more than 6 months. Treatment-related adverse events of any grade occurred in 26 patients (76%), most commonly fatigue (29%) and pruritus (15%). Grades 3 and 4 treatment-related adverse events were reported in 9 patients (26%), with pneumonitis, gastrointestinal disorders, and laboratory disorders mostly seen. One treatment-related death was due to pneumonitis and probably initiated by concurrent amiodarone therapy. PD-L1 was expressed on tumor cells in nine samples (27%), but did not correlate with outcome. CONCLUSIONS: Single-agent nivolumab has meaningful clinical efficacy and a manageable safety profile in pre-treated patients with mesothelioma. PD-L1 expression does not predict for response in this population.

New cellular markers at diagnosis are associated with isolated central nervous system relapse in paediatric B-cell precursor acute lymphoblastic leukaemia.

In childhood acute lymphoblastic leukaemia (ALL), central nervous system (CNS) involvement is rare at diagnosis (1-4%), but more frequent at relapse (~30%). Because of the significant late sequelae of CNS treatment, early identification of patients at risk of CNS relapse is crucial. Using microarray-analysis, we discovered multiple differentially expressed genes between B-cell precursor (BCP) ALL cells in bone marrow (BM) and BCP-ALL cells in cerebrospinal fluid (CSF) at the time of isolated CNS relapse. After confirmation by real-time quantitative polymerase chain reaction, selected genes (including SCD and SPP1) were validated at the protein level by flowcytometric analysis of BCP-ALL cells in CSF. Further flowcytometric validation showed that a subpopulation of BCP-ALL cells (>1%) with a 'CNS protein profile' (SCD positivity and increased SPP1 expression) was present in the BM at diagnosis in patients who later developed an isolated CNS relapse, whereas this subpopulation was <1% or absent in all other patients. These data indicate that the presence of a (small) subpopulation of BCP-ALL cells with a 'CNS protein profile' at diagnosis (particularly SCD-positivity) is associated with isolated CNS relapse. Such information can be used to design new diagnostic and treatment strategies that aim at prevention of CNS relapse with reduced toxicity.

Differential activation of the death receptor pathway in human target cells induced by cytotoxic T lymphocytes showing different kinetics of killing.

BACKGROUND AND OBJECTIVES: Cytotoxic T lymphocytes (CTL) may use two effector mechanisms to kill their target cells: perforin (PFN) and granzyme B (GrB)-dependent granule-mediated cell death and death receptor-mediated cell death. Controversy exists whether, in addition to PFN/GrB-mediated apoptosis, death receptor-induced apoptosis contributes to the elimination of human tumor cells by CTL. DESIGN AND METHODS: Since the two CTL-mediated effector mechanisms differ in time required to eliminate target cells, lysis of target cells was analyzed using CTL clones with slow and rapid kinetics of killing derived from a patient with chronic myeloid leukemia. To determine the involvement of the death receptor pathway, a retroviral construct encoding the antiapoptotic gene FLICE inhibitory protein (FLIP) was introduced into these target cells. RESULTS: A CTL clone capable of killing 50% of the target cells within 2 hours of incubation primarily acted by release of PFN and GrB. In contrast, two CTL clones showing slower target cell killing kinetics partially used the death receptor pathway (approximately 30% inhibition by FLIP). INTERPRETATION AND CONCLUSIONS: We demonstrated that the death receptor pathway contributes to T-cell-mediated cell death if not all target cells are destroyed by release of PFN and GrB.

The mechanisms of Ara-C-induced apoptosis of resting B-chronic lymphocytic leukemia cells.

BACKGROUND AND OBJECTIVES: Cytarabine (Ara-C) is commonly used for the treatment of acute leukemia. Incorporation of Ara-C into DNA is a key event in the mechanism of killing of proliferating leukemic cells. Previously, we demonstrated that Ara-C was cytotoxic to proliferating but not to resting (G(O)) malignant cells from patients with acute leukemia. In contrast, here we show unexpected apoptosis of G(O) B-chronic lymphocytic leukemia (CLL) cells by Ara-C in a dose-dependent manner. In this study we analyzed which cellular processes were involved in Ara-C-mediated killing of G(O)-B-CLL cells. DESIGN AND METHODS: Using primary B-CLL cells (>98% in G(O)), we examined the mechanisms of Ara-C-mediated apoptosis in resting G(O) cells. CFSE-based cytotoxicity assays combined with cell cycle analysis were used to perform a long-term analysis of Ara-C-mediated killing of B-CLL cells. The effects of Ara-C on DNA and RNA synthesis were studied using various 3H-incorporation experiments. RESULTS: Ara-C-mediated cell death of B-CLL cells showed the characteristics of normal apoptosis, such as phosphatidyl serine exposure and caspase activation. The mechanism of killing of quiescent B-CLL cells by Ara-C was shown not to be dependent on DNA replication. In contrast, CD40L-activated B-CLL cells showed S-phase-specific depletion of proliferating CLL cells. We demonstrated that Ara-C was converted into its active triphosphate by G(O)-B-CLL cells, coinciding with a 30% inhibition of RNA synthesis. INTERPRETATION AND CONCLUSIONS: In conclusion, our data indicate that Ara-C can induce apoptosis in resting G(O)-B-CLL cells using a mechanism independent of cell proliferation and DNA replication but associated with inhibition of RNA synthesis and downregulation of Mcl-1.