Case Report: Iparomlimab and Tuvonralimab-based therapy for epithelioid malignant peritoneal mesothelioma: a three-case series

Our plain-English summary of Case Report: Iparomlimab and Tuvonralimab-based therapy for epithelioid malignant peritoneal mesothelioma: a three-case series, by Z. Xu, L. Zhu, Y. Fang, et al (Frontiers in Oncology, 2026).

The study

• Authors: Z. Xu, L. Zhu, Y. Fang, Y. Jiang
• Journal: Frontiers in Oncology
• Published: 2026;16:1914733
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Epithelioid malignant peritoneal mesothelioma (EMPM) is a rare and aggressive malignancy of serosal origin. Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy is generally reserved for carefully selected patients in whom adequate cytoreduction appears feasible, while evidence supporting systemic immunotherapy remains limited for patients with unresectable disease or those unable to tolerate intensive treatment. Iparomlimab and tuvonralimab (QL1706) is a fixed-ratio anti-PD-1/anti-CTLA-4 MabPair formulation that has shown preliminary antitumor activity in several advanced solid tumors, but clinical experience in EMPM remains scarce.

Case Presentation: We retrospectively describe three patients with EMPM diagnosed through integrated clinicopathologic assessment who received QL1706 either as monotherapy or in combination with an antiangiogenic agent. Treatment response was assessed by the treating team on serial computed tomography (CT) using Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) as the evaluation framework.

Results: Case 1 was a 53-year-old woman with a programmed death-ligand 1 (PD-L1) combined positive score (CPS) of 10. Diffuse peritoneal disease persisted after surgery and three sessions of postoperative catheter-based hyperthermic intraperitoneal chemotherapy. QL1706 plus bevacizumab subsequently produced stable disease with symptomatic improvement for approximately 7 months. Case 2 was an 89-year-old man with a PD-L1 CPS of 0 who was considered unsuitable for surgery or intensive chemotherapy. QL1706 plus dose-reduced lenvatinib achieved a partial response that remained ongoing for more than 10 months. Case 3 was a 70-year-old man with a PD-L1 CPS of 55 and pre-existing nephrotic syndrome. QL1706 monotherapy induced a rapid partial response, but treatment was discontinued because of worsening proteinuria and edema; the disease subsequently progressed, with a new intracranial lesion radiologically suspicious for metastasis.

Conclusion: QL1706-based therapy achieved disease control in all three patients with EMPM who had limited conventional treatment options, including a durable response in an elderly patient with PD-L1-negative disease and rapid tumor regression with QL1706 monotherapy. The contrasting clinical courses suggest that overall benefit depends not only on tumor sensitivity but also on the accompanying treatment strategy and baseline organ function.

Copyright © 2026 Xu, Zhu, Fang and Jiang.

In plain English

This case series described three patients with epithelioid malignant peritoneal mesothelioma at a hospital in Wenzhou, China, treated with QL1706 (iparomlimab and tuvonralimab), a drug combining two immunotherapy antibodies. The article did not report asbestos or other exposure histories. A 53-year-old woman with disease remaining after surgery and heated abdominal chemotherapy received QL1706 plus bevacizumab. Her best result was stable disease, lasting about 7 months before progression. An 89-year-old man judged unsuitable for surgery or intensive chemotherapy received QL1706 plus reduced-dose lenvatinib. He had a partial response, with no progression for more than 10 months at last follow-up. A 70-year-old man with a pre-existing kidney disorder (nephrotic syndrome) received QL1706 alone. His largest tumor shrank, but treatment was stopped when urine protein loss and swelling worsened. The disease then progressed, with a brain lesion suspected to be a metastasis. The authors concluded that QL1706-based therapy achieved disease control in all three patients and should be evaluated in larger studies. They noted the small number of patients and differing treatments.

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 case series (three cases)
• Who was studied: Three patients with epithelioid malignant peritoneal mesothelioma (EMPM) whose conventional treatment options were limited: a 53-year-old woman, an 89-year-old man and a 70-year-old man. The authors are at The First Affiliated Hospital, Wenzhou Medical University, China. Treatment began in 2025, with follow-up to February 2026.
• Exposure: No asbestos or other environmental or occupational exposure was reported. The treatment studied was QL1706 5 mg/kg every 3 weeks: with bevacizumab 7.5 mg/kg in Case 1, with lenvatinib 4 mg/day increased to 8 mg/day in Case 2, and alone in Case 3.
• Main results:
  • Case 1 (53-year-old woman, QL1706 plus bevacizumab): stable disease with symptom improvement for approximately 7 months.
  • Case 1: no grade 3 or higher treatment-related adverse events were recorded.
  • Case 2 (89-year-old man, QL1706 plus dose-reduced lenvatinib): the liver lesion decreased from 53 × 50 mm at baseline to approximately 28 × 26 mm after five cycles, a partial response.
  • Case 2: the partial response was ongoing for more than 10 months at last follow-up.
  • Case 2: a mild infusion-related reaction resolved with symptomatic management.
  • Case 3 (70-year-old man, QL1706 alone): the largest lesion decreased from approximately 97 × 65 mm to approximately 67 × 32 mm after about 8 weeks, classified as a partial response.
  • Case 3: proteinuria and edema worsened during treatment, and QL1706 was stopped. The authors stated that an immune-mediated contribution could not be excluded.
  • Case 3: the disease then progressed, with a new brain lesion radiologically suspicious for metastasis (not confirmed by pathology). Progression-free survival was approximately 4 months.
  • PD-L1 CPS values were 10, 0 and 55 in Cases 1, 2 and 3. Outcomes did not improve with higher expression, and the most durable response occurred in the patient with a CPS of 0.
• The authors' conclusion: The authors concluded that QL1706-based therapy achieved disease control in all three patients. They also concluded that benefit depended on tumor sensitivity, the accompanying treatment, and the patient's ability to remain on therapy, and that QL1706 should be evaluated in larger studies.
• Limitations the authors state:
  • Small sample size and differing treatment regimens.
  • Response was judged by the treating team, with no blinded independent imaging review.
  • Follow-up information from the outside hospital was incomplete for Case 3.
  • The cases cannot separate the effect of QL1706 from that of the antiangiogenic drugs, and do not allow monotherapy to be compared with combination therapy.

Topics

Medical terms in this study, explained in our Lexicon: Epithelioid, Peritoneal Mesothelioma, Cytoreductive Surgery, HIPEC, Immunotherapy, Unresectable, CTLA-4, PD-L1.

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