Brief Report: Real-World Toxicity and Survival of Combination Immunotherapy in Pleural Mesothelioma-RIOMeso

Durvalumab Combined With Pemetrexed-Based Chemotherapy in Trial-Ineligible Patients With Mesothelioma: A Brief Report

Introduction

Chemoimmunotherapy is associated with promising activity in mesothelioma in phase II to III trials. Studies exploring this approach in patients ineligible for clinical trials are lacking. We assembled a cohort of patients receiving pemetrexed-based chemotherapy with durvalumab outside of clinical trials.

Methods

Patients with pleural mesothelioma received pemetrexed plus durvalumab or carboplatin plus pemetrexed plus durvalumab via off-label authorization at Massachusetts General Hospital. Response to chemoimmunotherapy was assessed per modified Response Evaluation Criteria in Solid Tumors version 1.1. A retrospective chart review was conducted to assess safety per Common Terminology Criteria for Adverse Events version 5.0.

Results

Twelve patients were included in the series. Nine patients were treated with triplet chemoimmunotherapy. Three patients received doublet chemoimmunotherapy because of platinum ineligibility. Concurrent active malignancies and symptomatic cardiac disease were present in three patients (25%) and two patients (17%), respectively. Ten patients had measurable disease at baseline. With the triplet regimen, partial responses were observed in four of the seven (57%) patients with measurable disease. All three patients receiving pemetrexed plus durvalumab had measurable disease and experienced a partial response. Primary progression was not observed with either regimen. Overall, eight patients (75%) remained on treatment for more than 6 months without progression. Five patients developed immune-related adverse events (n = 1 each pyrexia, arthritis, neutropenia, Raynaud's disease, stomatitis). Three patients discontinued treatment because of toxicity or symptomatic comorbid conditions (n = 1 grade 3 heart failure, n = 1 grade 2 fever + progressive kidney cancer, n = 1 grade 2 fatigue).

Conclusions

Antitumor activity of chemoimmunotherapy reported in phase II to III clinical trials is generalizable to the broader patient population with mesothelioma. However, the tolerability of chemoimmunotherapy is impacted by comorbid conditions in real-world patients.

Breaking Through: Immunotherapy Innovations in Pleural Mesothelioma

The prognosis of pleural mesothelioma (PM) is poor and conventional chemotherapy regimens have shown limited antitumor activity. Recent use of immune checkpoint inhibitors (ICIs) has shown promise, with CheckMate-743 trial establishing nivolumab plus ipilimumab as first line treatment in unresectable PM. Nevertheless, real-world applicability as well as differential benefit of immunotherapy according to histologic are areas of active debate. In addition, increased incidence of immune-related adverse events (IRAEs) and high discontinuation rates highlight the need for careful patient selection. While ICIs represent a significant advancement in PM treatment, ongoing research is necessary to refine their use, potentially through biomarker-informed approaches, and manage associated toxicities. This review highlights the evolving landscape of immunotherapy and associated controversies in PM.

Immune checkpoint inhibitors in the treatment of pleural mesothelioma: insights from real-world data

BACKGROUND

Immune checkpoint inhibitors (ICIs) have recently emerged as a promising strategy for the treatment of pleural mesothelioma (PM).

METHODS

This retrospective study evaluated treatment efficacy and safety in Japanese patients with PM treated with nivolumab and ipilimumab (N + I group: 41 patients) as first-line therapy and nivolumab monotherapy (N group: 33 patients) as second- or later-line treatment.

RESULTS

The median overall survival (OS) and progression-free survival (PFS) were not reached and 10.4 months in the N + I group, and 8.6 months and 3.5 months in the N group, respectively. Treatment-related adverse events (TRAEs) of any grade occurred in 68.3% of the N + I group and 72.7% of the N group, with grade 3-4 TRAEs in 19.5% and 12.1% of patients, respectively. Patients with an ECOG PS 0-1 had significantly better OS and PFS in both treatment groups (p < 0.001). In the N + I group, OS was significantly better in patients with TRAEs (p = 0.020) and in those with the epithelioid subtype (p = 0.047), although PFS was not significantly different (p = 0.138 and p = 0.154, respectively). In the N group, both OS (p = 0.007) and PFS (p = 0.048) were significantly longer in patients with TRAEs.

CONCLUSION

This study provides valuable real-world clinical evidence of the efficacy and safety of nivolumab plus ipilimumab and nivolumab monotherapy in Japanese patients with PM. These results support the use of ICIs as a viable treatment option for advanced or relapsed disease.

A Perspective on the MARS2 Trial

INTRODUCTION

The phase 3 randomized controlled trial of extended pleurectomy decortication and chemotherapy versus chemotherapy alone for pleural mesothelioma (PM) (MARS2) reported "extended pleurectomy decortication was associated with worse survival to 2 years, and more serious adverse events for individuals with resectable PM, compared with chemotherapy alone." These results have led to considerable discourse regarding the future role of surgery for PM, and there has not been unanimity in the mesothelioma surgical community regarding the trial interpretation. This "perspective" evaluates MARS2 using internationally renowned PM experts who either agreed with the trial interpretation or who found issues with its conduct which may have influenced the results.

METHODS

A facilitator (HP) worked with team leaders (GW, IO) to assemble individuals offering opinions regarding the trial and its conclusions. Arguments agreeing or not agreeing with the trial interpretation were written only after publication of the full trial. Once both arguments were received by the facilitator, the individual team manuscripts were combined and sent to each team allowing editing for changes in perceived factual errors.

FINDINGS

Insightful arguments include (but were not limited to) the difficulties yet advantages of randomization, quality assurance, selection of histologic subtypes, the timing of randomization, use of preoperative staging, statistical methods, and reasons for surgical mortality.

CONCLUSIONS

The decision to operate for PM in the future will continue to be defined by consensus guidelines and health payer willingness, and the interpretation of MARS2 may play an important role in modulating the role of surgery in the future.

Why the MARS2 Trial Does Not Mean the End of All Mesothelioma Surgery

BACKGROUND/OBJECTIVES

The published report of the MARS2 trial suggested that the addition of extended pleurectomy/decortication to chemotherapy for pleural mesothelioma was harmful. Thus, the report goes on, all disease should be considered as unresectable and no further mesothelioma surgery for survival benefit should be considered. This statement has changed clinical practice in the UK; however, the design of the MARS2 trial has several limitations which should prevent its conclusions being over interpreted. These limitations include the following: the inclusion of too many patients who would fall outside contemporary selection criteria including age, co-morbidity and histology; the unnecessary resection of too much tissue, particularly the diaphragm, and operating on patients too late in the disease process due to less than rigorous staging.

METHODS

We retrospectively analysed the selection and outcome of data of 79 of the 158 (50%) patients who underwent surgery in the surgical arm of the MARS2 study who were operated by the authors in four of the five trial surgical centres. We revised the clinical staging of these patients by applying the criteria in the forthcoming 9th TNM edition including the measurement of pleural thickness.

RESULTS

Based on reported guidelines, the selection for surgery was reset as stage I or II epithelioid PM. We found that 52 (66%) of these patients (group A) would not have been considered for surgery using contemporary selection criteria for the following reasons: non-epithelioid PM in 5; cT/4 in 35; cT2N1 in 10 and 2 cT2N0 (pN1), which would have been detected on preoperative mediastinal biopsy. Of the 27 (34%) trial patients fulfilling current criteria (group B), 12 were cT1N0, 1 was cT1N1, 6 were cT1N0pN1 and 8 were cT2N0, all with epithelioid PM. The median survival of group B was 32 (1-72) months, which was significantly higher than in group A: 8.5 (1-55) months, p < 0.0005 (Mann-Whitney).

CONCLUSIONS

As contemporary selection criteria were not applied in MARS2, its conclusions cannot be universally applied to all those with PM. Together with the favourable postoperative survival in this selected group, we suggest that there is still scope for a further trial of surgery in early-stage epithelioid mesothelioma.

Follow-up after first-Line nivOlumab plus ipilimumab in patients with diffuse pleuRal mesotheliomA: a real-world Dutch cohort study-FLORA

BACKGROUND

Diffuse pleural mesothelioma (dPM) is an aggressive malignancy, primarily treated with palliative systemic therapy. Since 2022, nivolumab-ipilimumab (nivo/ipi) has replaced chemotherapy as the standard first-line treatment for dPM in the Netherlands. Chemotherapy remains a rational second-line treatment. The real-world effectiveness of second-line treatment after doublet immunotherapy remains unknown. The FLORA study aimed to provide an overview of treatment patterns in patients with dPM after first-line nivo/ipi and evaluate the effectiveness of second-line chemotherapy based on real-world data.

PATIENTS AND METHODS

FLORA was a Dutch multicenter retrospective cohort study. Clinical data were collected from the medical records. The primary endpoints were treatment patterns after nivo/ipi and median overall survival (mOS) of patients receiving second-line chemotherapy. The secondary endpoints were objective response rate (ORR), median progression-free survival (mPFS) of second-line chemotherapy, and subgroup analyses (Eastern Cooperative Oncology Group performance status and histological subtype). The study also updated the mOS for first-line nivo/ipi patients.

RESULTS

Between May 2021 and July 2023, 277 patients with dPM receiving first-line nivo/ipi therapy were included. Sixty-eight percent of the patients were male, with a median age of 72 years (interquartile range 67-77 years). The histological subtypes were epithelioid (62%), sarcomatoid (22%), biphasic (13%), and unknown (3%). One hundred and two (47%) of the 218 patients with disease progression received second-line treatment, of whom 83 received second-line platinum-pemetrexed chemotherapy. The mOS and mPFS for second-line chemotherapy were 8.2 months ([95% confidence interval (CI) 7.4-9.1 months] and 5.6 months (95% CI 4.9-6.3 months), respectively, with an ORR of 37%. Poor performance score was the main reason for not receiving second-line treatment.

CONCLUSION

This study provides the first real-world data on subsequent treatment of patients with dPM with disease progression on nivo/ipi, resulting in an mOS of 8.2 months after second-line chemotherapy.

Cytoreductive surgery in diffuse pleural mesothelioma. What have we learnt from MARS2, EORTC-L1205 and other recent studies?

Cytoreductive surgery remains controversial in pleural mesothelioma. The MARS2 trial suggested that extended pleurectomy decortication following neoadjuvant chemotherapy was associated with no survival benefit, more serious adverse events and poorer quality of life than systemic chemotherapy alone in patients with resectable pleural mesothelioma. However, patient selection, chemotherapy scheme, high surgical mortality (9 %) and poor outcomes in the surgical cohort have been raised by mesothelioma experts as potential issues in MARS2. The EORTC-L1205trial reported high morbidity, but low surgical mortality (1.7 %) and more favourable outcomes, suggesting that well-selected patients could benefit from extended pleurectomy decortication and systemic chemotherapy. Other recently-published studies show that cytoreductive surgery remains a valuable option in well-selected patients offering median survivals of 34-38 months, when the best systemic options combining chemotherapy agents, anti-angiogenics or immune checkpoint inhibitors offer median survivals of 18-24 months. Careful patient selection is essential to avoid futile or detrimental surgery and there is evidence that preservation of the diaphragm is associated with lower morbidity and mortality, better long-term outcomes.

Real-World efficacy and safety of combination nivolumab plus ipilimumab for Untreated, Unresectable, pleural Mesothelioma: The Meso-Immune (GFPC 04-2021) trial

BACKGROUND

First-line standard-of-care for unresectable, pleural mesothelioma (PM) changed with the phase 3 CheckMate 743 study results, showing that nivolumab plus ipilimumab (Nivo + Ipi) significantly extended overall survival (OS) versus platinum + pemetrexed chemotherapy for PM (median OS 18.1 versus 14.1 months; hazard ratio: 0.74; p = 0.002). Efficacy and safety data in real-world (rw) settings are needed to confirm these results.

METHODS

This French multicenter, retrospective cohort study was undertaken to assess the outcomes of treatment-naïve PM patients given Nivo + Ipi via an early-access program (EAP). The primary objective was investigator-assessed real world -progression-free survival (PFS). The secondary objectives were the combination's -overall survival (OS) and safety.

RESULTS

From 1 April 2021 to 15 Feb 2022, the analysis included 201 of the 305 EAP-enrolled patients treated in 63 centers (79.6 % men; median age: 75 years; 91.8 % Eastern Cooperative Oncology Group performance status (ECOG-PS) 0/1; 74.5 % epithelioid histology). With median (95 % CI) follow-up for all patients of 18.4 (17.7-19.2) months, -PFS and OS were 6.3 (5.3-7.5) and 18.9 (17.6-not reached (NR)) months, with 1-year OS at 66.4 % (60.1-73.3 %). Median OS and 1-year survival rates were 21.0 (18.7-NR) and 70.8 % (63.9 %-780.6 %), and 14.1 (10.9-21.0) months and 54.9 % (42.8 %-70.4 %) for epithelioid and non-epithelioid PM subgroups, respectively. PFS was equal between the two subgroups. Grade 3-4 adverse events occurred in 23.3 % of patients and three deaths were treatment-related.

CONCLUSIONS

For this unselected PM population, efficacy and safety outcomes compared favorably with CheckMate 743 trial results.