Successful Response to First-Line Carboplatin, Pemetrexed, and Bevacizumab for Peritoneal Mesothelioma: Two Case Reports

Our plain-English summary of Successful Response to First-Line Carboplatin, Pemetrexed, and Bevacizumab for Peritoneal Mesothelioma: Two Case Reports, by T. Koizumi, S. Kanda, N. Sekiguchi, et al (Case Reports in Oncology, 2025).

The study

• Authors: T. Koizumi, S. Kanda, N. Sekiguchi, T. Noguchi, S.I. Eda, H. Kitahara
• Journal: Case Reports in Oncology
• Published: 2025;18(1):278-285
• Type of article: Case report
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Introduction: Peritoneal mesothelioma is an extremely rare malignancy of the peritoneum. It has a poor prognosis, and the optimal systemic chemotherapy remains controversial. Here, we report two cases of peritoneal mesothelioma with long-term survival and complete response to carboplatin, pemetrexed, and bevacizumab chemotherapy.

Case Presentation: Both patients were treated with six cycles of carboplatin (AUC 5), pemetrexed (750 mg/m2), and bevacizumab (15 mg/kg) followed by pemetrexed and bevacizumab as maintenance therapy. Partial response continued for over 6 years in case 1, and complete response was obtained in case 2. The patient in case 1 died after 7 years due to accidental pneumonia, and the patient in case 2 remained disease-free for over 2 years after initiation of chemotherapy.

Conclusion: Little information is available regarding angiogenesis in malignant peritoneal mesothelioma, and carboplatin/pemetrexed/bevacizumab are off-labeled chemotherapy by Japanese healthcare system as yet. However, our experience suggested that combined chemotherapy with bevacizumab is a feasible option for systemic chemotherapy in cases of peritoneal mesothelioma.

© 2025 The Author(s). Published by S. Karger AG, Basel.

In plain English

This article reported two cases of epithelioid peritoneal mesothelioma (a cancer of the abdominal lining) treated in Japan. Case 1 was a 68-year-old woman referred in 2017 with massive abdominal fluid. Case 2 was a 76-year-old man in whom fluid was found on a routine screening ultrasound in 2022. Detailed interviews found no asbestos exposure in either patient. Both received six cycles of carboplatin, pemetrexed and bevacizumab, then maintenance pemetrexed and bevacizumab. In case 1, maintenance ran 30 cycles until protein appeared in the urine. The disease remained controlled at 3 and 6 years, and the patient died of a respiratory infection 7 years after diagnosis without relapse. In case 2, chemotherapy stopped at 18 months because of swelling and urine protein. Abnormal scan activity disappeared 2 years after chemotherapy began, which the authors considered a complete response, and the patient was alive 2 years after diagnosis. Neither patient had blood-clot events. The authors concluded that chemotherapy combined with bevacizumab may be a feasible option for this disease.

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: case report (two cases)
• Who was studied: Two Japanese patients with epithelioid peritoneal mesothelioma. Case 1 was a 68-year-old woman (a housewife) referred in August 2017 with massive ascites. Case 2 was a 76-year-old man (an employee) referred in October 2022 after ascites was seen on ultrasound at a routine annual health screening.
• Exposure: Neither patient had a history of asbestos exposure on detailed medical interview. The treatment reported was six cycles of carboplatin (AUC 5), pemetrexed (750 mg/m2) and bevacizumab (15 mg/kg), followed by pemetrexed and bevacizumab maintenance.
• Main results:
  • Both patients received six cycles of carboplatin (AUC 5), pemetrexed (750 mg/m2) and bevacizumab (15 mg/kg), followed by pemetrexed and bevacizumab maintenance. Carboplatin was used instead of cisplatin because of a congenital single kidney in case 1, and because of advanced age and low kidney filtration (51 mL/min/1.73 m2) in case 2.
  • Case 1: maintenance therapy continued for 30 cycles until proteinuria (3+) developed, and was followed by pemetrexed alone.
  • Case 1: the disease was well controlled at 3 years and at 6 years, despite chemotherapy having been stopped.
  • Case 1: with no relapse of peritoneal mesothelioma, the patient died of a respiratory infection 7 years after the initial diagnosis.
  • Case 2: lesions with FDG uptake on PET/CT disappeared 2 years after chemotherapy was started, and the response was considered a complete response.
  • Case 2: after 18 cycles of maintenance, the patient developed edema and proteinuria (2+), and chemotherapy was stopped 18 months after diagnosis. Both problems improved within 3 months of stopping.
  • Case 2: the patient refused surgery and was alive 2 years after the initial diagnosis.
  • Neither patient had any thrombotic (blood-clot) events during the clinical course.
• The authors' conclusion: The authors concluded that little is known about angiogenesis in peritoneal mesothelioma, but that their experience suggested chemotherapy combined with bevacizumab may be a feasible option for systemic chemotherapy in these patients. They noted that the carboplatin/pemetrexed/bevacizumab regimen is not yet approved (off-label) in the Japanese healthcare system.

Topics

Medical terms in this study, explained in our Lexicon: Carboplatin, Pemetrexed (Alimta), Bevacizumab, Peritoneal Mesothelioma, Peritoneum, Prognosis, Chemotherapy, Angiogenesis.

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• Pemetrexed Maintenance Therapy Following Bevacizumab-Containing First-Line Chemotherapy in Advanced Malignant Pleural Mesothelioma: A Case Report and Literatures Review — X.Q. Jing, L. Zhou, et al. (2016)
• MiR-193b-3p and miR-132-3p as prognostic biomarkers of survival in pleural mesothelioma patients treated with first-line bevacizumab plus pemetrexed-platinum chemotherapy in the IFCT-0701 MAPS phase 3 trial — G. Levallet, C. Creveuil, et al. (2025)
• Tumour Treating Fields in combination with pemetrexed and cisplatin or carboplatin as first-line treatment for unresectable malignant pleural mesothelioma (STELLAR): a multicentre, single-arm phase 2 trial — G.L. Ceresoli, J.G. Aerts, et al. (2019)
• Carboplatin plus pemetrexed as first-line treatment of patients with malignant pleural mesothelioma: a phase II study — N. Katirtzoglou, I. Gkiozos, et al. (2010)
• PD-L1 pfeRNAs as blood-based predictors of treatment response of unresectable malignant pleural mesothelioma patients administered Durvalumab with cisplatin and pemetrexed as first-line therapy — A. Gurau, S. Yamauchi, et al. (2025)

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