Comparative efficacy of immune checkpoint inhibitors versus chemotherapy alone in diffuse pleural mesothelioma

Our plain-English summary of Comparative efficacy of immune checkpoint inhibitors versus chemotherapy alone in diffuse pleural mesothelioma, by X. Zhang, L. Chang, Q. Ma, et al (Thoracic Cancer, 2024).

The study

• Authors: X. Zhang, L. Chang, Q. Ma, Q. Zhang, W. Xu, Q. Li
• Journal: Thoracic Cancer
• Published: 2024;15(20):1590-1597
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: This study aimed to investigate the effects of immune checkpoint inhibitors (ICIs) versus chemotherapy on the prognosis of real-world diffuse pleural mesothelioma patients in China.

Methods: Clinical data of 90 patients with diffuse pleural mesothelioma from 2019 to 2022 were collected from Harbin Medical University Cancer Hospital. Patients were divided into two groups: the ICIs-treated group (n = 46) and the chemotherapy-only group (n = 44). The efficacy and safety of immunotherapy relative to chemotherapy at different treatment stages were explored.

Results: The median progression-free survival (PFS) was 10.0 and 7.0 months, and the median overall survival (OS) was 24.7 and 15.8 months in the ICIs-treated group and the chemotherapy group, respectively. The ICIs-treated group showed an 11% increase in objective response rate (ORR) (52.2% vs. 41.0%) and an 8.0% increase in disease control rate (DCR) (78.3% vs. 70.0%) compared to the chemotherapy group. The Kaplan-Meier curves demonstrated significant PFS (HR: 0.61; 95% CI: 0.38-0.98; p = 0.038) and OS (HR: 0.47; 95% CI: 0.26-0.86; p = 0.011) benefits of receiving immunotherapy over chemotherapy alone. Subgroup analysis according to treatment timing showed the same trend.

Conclusion: In patients with nonsurgical diffuse pleural mesothelioma, immunotherapy achieved better survival benefits compared to chemotherapy in both first- and second-/third-line treatments. The early addition of immunotherapy improved survival in patients with nonsurgical diffuse pleural mesothelioma.

© 2024 The Author(s). Thoracic Cancer published by John Wiley & Sons Australia, Ltd.

In plain English

This was a retrospective study of 90 patients with diffuse pleural mesothelioma who had not had radical surgery and were treated at Harbin Medical University Cancer Hospital in China from 2019 to 2022. It compared 46 patients who received immune checkpoint inhibitors (ICIs), such as nivolumab with or without ipilimumab, camrelizumab, sintilimab or tislelizumab, with 44 patients who received chemotherapy only. The study did not look at asbestos exposure. Median progression-free survival was 10.0 months in the ICI group and 7.0 months in the chemotherapy group. Median overall survival was 24.7 and 15.8 months. Hazard ratios favored the ICI group for progression-free survival (0.61; 95% CI 0.38 to 0.98) and overall survival (0.47; 95% CI 0.26 to 0.86). Patients who started ICIs as first-line treatment did significantly better than the chemotherapy group on both measures. For second-line treatment, the difference in overall survival was not statistically significant. Side effects of any grade occurred in 54.3% of the ICI group and 65.9% of the chemotherapy group. The authors concluded that immunotherapy should be added as early as possible, and they noted that their single-center sample was small.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective single-center study comparing treatment groups from hospital records
• Who was studied: 90 patients with diffuse pleural mesothelioma who had not undergone radical surgery, treated at Harbin Medical University Cancer Hospital, China, 2019 to 2022. 46 were in the ICIs-treated group and 44 in the chemotherapy-only group.
• Exposure: Not an asbestos exposure study. The exposures compared were treatments. The ICI group had at least two cycles of immune checkpoint inhibitors (nivolumab with or without ipilimumab, camrelizumab, sintilimab, tislelizumab, others). The chemotherapy group had pemetrexed plus platinum, pemetrexed plus platinum plus bevacizumab, or platinum plus gemcitabine, and never received ICIs.
• Main results:
  • Median progression-free survival was 10.0 months in the ICIs-treated group versus 7.0 months in the chemotherapy-only group. Median overall survival was 24.7 versus 15.8 months.
  • For all patients, ICI treatment versus chemotherapy alone: progression-free survival HR 0.61 (95% CI 0.38 to 0.98; p = 0.038); overall survival HR 0.47 (95% CI 0.26 to 0.86; p = 0.011).
  • Objective response rate was 24 of 46 (52.2%) in the ICIs-treated group versus 18 of 44 (41.0%) in the chemotherapy-only group. No patient had a complete response. Table 1 gives p = 0.547 for the comparison of response categories.
  • Disease control rate in Table 2 was 36 of 46 (78.3%) in the ICIs-treated group versus 31 of 44 (70.5%) in the chemotherapy-only group.
  • First-line subgroup (23 ICI patients versus 44 chemotherapy patients): progression-free survival HR 0.44 (95% CI 0.23 to 0.83; p = 0.009). Overall survival HR 0.26 (95% CI 0.11 to 0.64; p = 0.002).
  • Second-line subgroup (21 ICI patients versus 17 chemotherapy patients): progression-free survival HR 0.47 (95% CI 0.24 to 0.94; p = 0.026). The overall survival difference was not statistically significant (HR 0.70; 95% CI 0.30 to 1.64; p = 0.412).
  • Among ICI-treated patients, those who started ICIs at first line had better progression-free survival (HR 0.47; 95% CI 0.23 to 0.96; p = 0.033) and overall survival (HR 0.26; 95% CI 0.09 to 0.73; p = 0.007) than those who started at second or third line.
  • Treatment-related adverse events of any grade occurred in 25 of 46 (54.3%) ICI patients and 29 of 44 (65.9%) chemotherapy patients. Grade 3 or 4 events occurred in 2 (4.3%) and 4 (9.1%), respectively.
• The authors' conclusion: The authors concluded that, in nonsurgical diffuse pleural mesothelioma, immunotherapy gave a better survival benefit than chemotherapy in both first-line and second- or third-line treatment. They also concluded that immunotherapy should be added to treatment as early as possible.
• Limitations the authors state:
  • Small single-center sample, which may have caused statistical bias in some results.
  • Imaging makes it hard to measure changes in these tumors accurately, which may bias progression-free survival.
  • Many patients' specific tumor type was not recorded, so a large share had unknown histology (NOS).
  • No propensity score matching was done to remove differences between the treatment groups.
  • Survival data came mainly from telephone follow-up, which may have made some data differ from the actual situation.
  • The non-significant overall survival result in the second-line subgroup was attributed to the small number of patients.

Topics

Medical terms in this study, explained in our Lexicon: checkpoint inhibitors, Chemotherapy, Pleural Mesothelioma, Prognosis, Immunotherapy, Progression-Free Survival, Median Overall Survival, Kaplan-Meier Curve.

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• Efficacy and safety of PD-1/PD-L1 and CTLA-4 immune checkpoint inhibitors in the treatment of diffuse pleural mesothelioma: a systematic review and meta-analysis — P. Sun, D. Song, et al. (2025)
• Efficacy of Immune Checkpoint Inhibitors in Rare Tumours: A Systematic Review — F. Petrelli, F. Consoli, et al. (2021)
• Safety and efficacy of PD-1/PD-L1 immune checkpoint inhibitors in patients with pre-treated advanced stage malignant mesothelioma: a systematic review and meta-analysis — A. Zafar, A.A. Rashid, et al. (2024)
• Matter of TIME: the tumor-immune microenvironment of mesothelioma and implications for checkpoint blockade efficacy — J. Harber, T. Kamata, et al. (2021)
• Immune checkpoint inhibitors a new player in the therapeutic game of mesothelioma: New reality with new challenges — K. Parikh, L.E.L. Hendriks, et al. (2021)

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