Nowak, Anna K.

In this 5-year follow-up from the CheckMate 743 study in patients with unresectable pleural mesothelioma (PM), we evaluated updated efficacy and safety outcomes and biomarkers and performed treatment-switching analyses with first-line nivolumab plus ipilimumab versus chemotherapy. With a median follow-up of 66.8 months, nivolumab plus ipilimumab demonstrated continued overall survival (OS) benefit versus chemotherapy in all randomly assigned patients (5-year OS rates, 14% v 6%; hazard ratio [HR], 0.74 [95% CI, 0.62 to 0.88]); similar benefit was observed regardless of tumor histology. Of biomarker-evaluable patients treated with nivolumab plus ipilimumab (n = 242), high baseline monocytic myeloid-derived suppressor cell (M-MDSC) levels correlated with worse OS versus low M-MDSC levels (HR, 1.25 [95% CI, 1.09 to 1.43]). After adjusting for 24% of patients in the chemotherapy arm who received subsequent immunotherapy, nivolumab plus ipilimumab demonstrated continued OS benefit versus chemotherapy (HR, 0.64 [95% CI, 0.53 to 0.78]). No new safety signals were observed. These results demonstrate long-term, durable clinical benefit with nivolumab plus ipilimumab versus chemotherapy, which continued to be preserved even after treatment-switching adjustment in the chemotherapy arm. Exploratory analyses suggested greater benefit with nivolumab plus ipilimumab in the low M-MDSC subgroup. These results further support first-line nivolumab plus ipilimumab as standard of care for unresectable PM.

ImportanceArginine deprivation using ADI-PEG20 (pegargiminase) combined with chemotherapy is untested in a randomized study among patients with cancer. ATOMIC-Meso (ADI-PEG20 Targeting of Malignancies Induces Cytotoxicity-Mesothelioma) is a pivotal trial comparing standard first-line chemotherapy plus pegargiminase or placebo in patients with nonepithelioid pleural mesothelioma.ObjectiveTo determine the effect of pegargiminase-based chemotherapy on survival in nonepithelioid pleural mesothelioma, an arginine-auxotrophic tumor.Design, Setting, and ParticipantsThis was a phase 2-3, double-blind randomized clinical trial conducted at 43 centers in 5 countries that included patients with chemotherapy-naive nonepithelioid pleural mesothelioma from August 1, 2017, to August 15, 2021, with at least 12 months’ follow-up. Final follow-up was on August 15, 2022. Data analysis was performed from March 2018 to June 2023.InterventionPatients were randomly assigned (1:1) to receive weekly intramuscular pegargiminase (36.8 mg/m2) or placebo. All patients received intravenous pemetrexed (500 mg/m2) and platinum (75-mg/m2 cisplatin or carboplatin area under the curve 5) chemotherapy every 3 weeks up to 6 cycles. Pegargiminase or placebo was continued until progression, toxicity, or 24 months.Main Outcomes and MeasuresThe primary end point was overall survival, and secondary end points were progression-free survival and safety. Response rate by blinded independent central review was assessed in the phase 2 portion only.ResultsAmong 249 randomized patients (mean [SD] age, 69.5 [7.9] years; 43 female individuals [17.3%] and 206 male individuals [82.7%]), all were included in the analysis. The median overall survival was 9.3 months (95% CI, 7.9-11.8 months) with pegargiminase-chemotherapy as compared with 7.7 months (95% CI, 6.1-9.5 months) with placebo-chemotherapy (hazard ratio [HR] for death, 0.71; 95% CI, 0.55-0.93; P = .02). The median progression-free survival was 6.2 months (95% CI, 5.8-7.4 months) with pegargiminase-chemotherapy as compared with 5.6 months (95% CI, 4.1-5.9 months) with placebo-chemotherapy (HR, 0.65; 95% CI, 0.46-0.90; P = .02). Grade 3 to 4 adverse events with pegargiminase occurred in 36 patients (28.8%) and with placebo in 21 patients (16.9%); drug hypersensitivity and skin reactions occurred in the experimental arm in 3 patients (2.4%) and 2 patients (1.6%), respectively, and none in the placebo arm. Rates of poststudy treatments were comparable in both arms (57 patients [45.6%] with pegargiminase vs 58 patients [46.8%] with placebo).Conclusions and RelevanceIn this randomized clinical trial of arginine depletion with pegargiminase plus chemotherapy, survival was extended beyond standard chemotherapy with a favorable safety profile in patients with nonepithelioid pleural mesothelioma. Pegargiminase-based chemotherapy as a novel antimetabolite strategy for mesothelioma validates wider clinical testing in oncology.Trial RegistrationClinicalTrials.gov Identifier: NCT02709512

Abstract Purpose: In a post hoc analysis of the CATNON trial (NCT00626990), we explored whether adding temozolomide to radiotherapy improves outcome in patients with IDH1/2 wildtype (wt) anaplastic astrocytomas with molecular features of glioblastoma [redesignated as glioblastoma, isocitrate dehydrogenase–wildtype (IDH-wt) in the 2021 World Health Organization (WHO) classification of central nervous system tumors]. Patients and Methods: From the randomized phase III CATNON study examining the addition of adjuvant and concurrent temozolomide to radiotherapy in anaplastic astrocytomas, we selected a subgroup of IDH1/2wt and H3F3Awt tumors with presence of TERT promoter mutations and/or EGFR amplifications and/or combined gain of chromosome 7 and loss of chromosome 10. Molecular abnormalities including MGMT promoter methylation status were determined by next-generation sequencing, DNA methylation profiling, and SNaPshot analysis. Results: Of the 751 patients entered in the CATNON study, 670 had fully molecularly characterized tumors. A total of 159 of these tumors met the WHO 2021 molecular criteria for glioblastoma, IDH-wt. Of these patients, 47 received radiotherapy only and 112 received a combination of radiotherapy and temozolomide. There was no added effect of temozolomide on either overall survival [HR, 1.19; 95% confidence interval (CI), 0.82–1.71] or progression-free survival (HR, 0.87; 95% CI, 0.61–1.24). MGMT promoter methylation was prognostic for overall survival, but was not predictive for outcome to temozolomide treatment either with respect to overall survival or progression-free survival. Conclusions: In this cohort of patients with glioblastoma, IDH-wt temozolomide treatment did not add benefit beyond that observed from radiotherapy, regardless of MGMT promoter status. These findings require a new well-powered prospective clinical study to explore the efficacy of temozolomide treatment in this patient population.

Abstract Background Survival in patients with IDH1/2-mutant (mt) anaplastic astrocytomas is highly variable. We have used the prospective phase 3 CATNON trial to identify molecular factors related to outcome in IDH1/2mt anaplastic astrocytoma patients. Methods The CATNON trial randomized 751 adult patients with newly diagnosed 1p/19q non-codeleted anaplastic glioma to 59.4 Gy radiotherapy +/− concurrent and/or adjuvant temozolomide. The presence of necrosis and/or microvascular proliferation was scored at central pathology review. Infinium MethylationEPIC BeadChip arrays were used for genome-wide DNA methylation analysis and the determination of copy number variations (CNV). Two DNA methylation-based tumor classifiers were used for risk stratification. Next-generation sequencing (NGS) was performed using 1 of the 2 glioma-tailored NGS panels. The primary endpoint was overall survival measured from the date of randomization. Results Full analysis (genome-wide DNA methylation and NGS) was successfully performed on 654 tumors. Of these, 432 tumors were IDH1/2mt anaplastic astrocytomas. Both epigenetic classifiers identified poor prognosis patients that partially overlapped. A predictive prognostic Cox proportional hazard model identified that independent prognostic factors for IDH1/2mt anaplastic astrocytoma patients included; age, mini-mental state examination score, treatment with concurrent and/or adjuvant temozolomide, the epigenetic classifiers, PDGFRA amplification, CDKN2A/B homozygous deletion, PI3K mutations, and total CNV load. Independent recursive partitioning analysis highlights the importance of these factors for patient prognostication. Conclusion Both clinical and molecular factors identify IDH1/2mt anaplastic astrocytoma patients with worse outcome. These results will further refine the current WHO criteria for glioma classification.

TPS8582 Background: Argininosuccinate synthetase 1 (ASS1)-deficient malignant pleural mesothelioma (MPM) is sensitive to arginine deprivation therapy with pegylated arginine deiminase (ADI-PEG20), which also enhances the cytotoxicity of pemetrexed. The TRAP Phase 1 trial (NCT02029690) of ADI-PEG 20 combined with 1st-line pemetrexed (PEM) and cisplatin (CDDP) chemotherapy revealed a 94% disease control rate in non-epithelioid (biphasic and sarcomatoid) MPM subtypes characterized by a 75% rate of ASS1 loss. Thus, we plan to assess the efficacy of ADI-PEG20 or placebo combined with PEM and CDDP in patients (pts) with poor prognosis MPM in a randomized, placebo-controlled, double-blind phase 2/3 global trial. Methods: Up to 386 good performance (ECOG 0-1) pts with non-epithelioid malignant pleural mesothelioma will be enrolled in a phase 2/3 adaptive, biomarker-driven study design. Biopsies will be required prior to randomization: ASS1-agnostic pts will be enrolled initially (phase 2 stage) with an option to restrict enrolment to ASS1-deficient MPM (phase 3 stage). Pts will be randomized to receive weekly ADI-PEG20 (36 mg/m2 IM) or placebo with standard doses of PEM and CDDP for a maximum of 18 weeks (6 cycles) of treatment. Pts who develop CDDP toxicity may be switched to carboplatin. Pts will be assessed every 6 weeks using modified RECIST (RECIST 1.1 allowed for pts with significant extrathoracic disease). The primary endpoint for the phase 2 stage will be overall response rate (ORR) with secondary endpoints of overall survival (OS), safety and toxicity. The phase 2 will test ORR proportions with the placebo triplet set at 15% vs. 35% for the ADI-PEG 20 triplet, with a 1:1 randomization, 80% power. After recruitment of 176 pts, the phase 2 will convert to a phase 3 study with the primary endpoint of OS. In summary, ATOMIC-Meso is the first triplet chemotherapy study to assess the role of targeted arginine deprivation in aggressive subtypes of mesothelioma. Pt accrual has commenced across the US and Asia, with enrolment due in Europe and Australia by 2nd quarter of 2017. [Trial sponsored by Polaris Group]. Clinical trial information: NCT02709512.