Efficacy and safety of novel multiple-chain DAP-CAR-T cells targeting mesothelin in ovarian cancer and mesothelioma: a single-arm, open-label and first-in-human study

Our plain-English summary of Efficacy and safety of novel multiple-chain DAP-CAR-T cells targeting mesothelin in ovarian cancer and mesothelioma: a single-arm, open-label and first-in-human study, by T. Xu, T. Tian, C. Wang, et al (Genome Medicine, 2024).

The study

• Authors: T. Xu, T. Tian, C. Wang, X. Chen, X. Zuo, H. Zhou, J. Bai, C. Zhao, S. Fu, C. Sun, T. Wang, L. Zhu, J. Zhang, E. Wang, M. Sun, Y. Shu
• Journal: Genome Medicine
• Published: 2024;16(1):133
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Despite remarkable achievements in applying chimeric antigen receptor (CAR)-T cells to treat hematological malignancies, they remain much less effective against solid tumors, facing several challenges affecting their clinical use. We previously showed that multichain DNAX-activating protein (DAP) CAR structures could enhance the safety and efficacy of CAR-T cells when used against solid tumors. In particular, mesothelin (MSLN)-targeted CAR-T cell therapy has therapeutic potential in MSLN-positive solid tumors, including ovarian cancer and mesothelioma.

Methods: In vitro cell killing assays and xenograft model were utilized to determine the anti-tumor efficacy of MSLN targeting DAP-CAR-T cells and other CAR-T cells. ELISA and flow cytometry analysis were used to assess the cytokine secretion capacity and proliferation ability. Eight patients with MSLN expression were enrolled to evaluate the safety and efficacy of MSLN-DAP CAR-T cell therapy. Single-cell sequencing was performed to explore the dynamics of immune cells in patients during treatment and to identify the transcriptomic signatures associated with efficacy and toxicity.

Results: We found that multichain DAP-CAR formed by combining a natural killer cell immunoglobulin-like receptor truncator and DAP12 exhibited better cytotoxicity and tumor-killing capacity than other natural killer cell-activated receptors associated with DAP12, DAP10, or CD3Z. The safety and efficacy of MSLN-DAP CAR-T cell therapy in patients with ovarian cancer and mesothelioma were evaluated in a single-arm, open-label clinical trial (ChiCTR2100046544); two patients achieved partial response, while four patients had a stable disease status. Furthermore, single-cell sequencing analysis indicated that KT032 CAR-T cell infusion could recruit more immune cells and temporarily remodel the TME.

Conclusions: Our study highlights the safety and therapeutic efficacy of multiple-chain DAP-CAR-T cell therapy targeting MSLN to treat patients with ovarian cancer and mesothelioma.

Trial Registration: ChiCTR.org.cn, ChiCTR2100046544 . May 21, 2021.

© 2024. The Author(s).

In plain English

This report combined laboratory work with a first-in-human, single-arm, open-label phase I trial of KT032, autologous T cells carrying a multiple-chain DAP (KIR-DAP12) chimeric antigen receptor targeting mesothelin. In cell-killing assays and a mouse xenograft model, the authors reported that KIR CAR-T cells killed mesothelin-low SKOV3 cells better than CARs built on NKP44, NKP46, NKP30 or NKG2D, and that only KIR CAR-T cells substantially inhibited or eradicated tumours. In the trial at the First Affiliated Hospital of Nanjing Medical University (August 2021 to February 2024), nine mesothelin-positive patients with recurrent refractory ovarian cancer (eight) or mesothelioma (one) were enrolled. Leukapheresis failed in one, eight were infused at 0.5, 1.0 or 1.5 million cells/kg after lymphodepletion, and two stopped early for rapid progression. Of six evaluable patients, two had a partial response and four stable disease. Median progression-free survival was 5.5 months and median overall survival 10.5 months. Five of six developed cytokine release syndrome (one grade 3, four grade 1). No immune effector cell-associated neurotoxicity syndrome was observed, although the adverse-event table listed one grade 3 episode of confusion. Single-cell sequencing was done on products and tumour samples.

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: Preclinical in vitro and mouse xenograft experiments plus a single-arm, open-label, single-centre, first-in-human phase I clinical trial with single-cell RNA sequencing
• Who was studied: Nine mesothelin-positive patients with advanced recurrent refractory ovarian cancer (eight) or mesothelioma (one) were enrolled from August 2021 to September 2022 at the First Affiliated Hospital of Nanjing Medical University (Jiangsu Province Hospital), China. Eight were infused and six were evaluable. NSG/nude mice bearing SKOV3 xenografts were also used.
• Exposure: A single intravenous infusion of autologous mesothelin-targeted multiple-chain DAP (KIR/DAP12) CAR-T cells (KT032) at 0.5, 1.0 or 1.5 million cells/kg, given after fludarabine and cyclophosphamide lymphodepletion
• Main results:
  • Preclinical: among the NK-receptor-based CAR designs tested in mice, only KIR CAR-T cells substantially inhibited or eradicated SKOV3 tumours
  • Clinical response in the six evaluable patients: two partial responses and four stable disease. All six progressed within 9 months.
  • Survival in the treated patients: median progression-free survival 5.5 months, median overall survival 10.5 months
  • Tumour measurements: Patient 1 had a 31% reduction in liver metastases and loss of peritoneal effusion. Patient 2 had a 42% reduction in the total maximum diameter of the measurable lesion. Other patients changed between -18.7% and +4.56%.
  • The authors stated an objective response rate of 33.3% (2/6) and a disease control rate of 100% over 3 months
  • Cytokine release syndrome occurred in five of the six evaluable patients (one grade 3, four grade 1)
  • Nausea occurred in 83% (5/6) of the evaluable patients. No immune effector cell-associated neurotoxicity syndrome was observed.
  • The table of treatment-related adverse events (n = 6) listed confusion in one patient (grade 3) and dizziness in two (grade 1)
  • Pharmacokinetics: CAR-T cells in peripheral blood peaked at about 7 days (6 to 10 days) after infusion, and were undetectable in most patients 40 days after infusion
  • The single mesothelioma patient (Patient 4, 0.5 million cells/kg) had stable disease with grade 1 CRS. Tumour samples taken 15 and 45 days after infusion were sequenced.
  • Single-cell sequencing of CAR-T products from four patients showed no significant differences in CD4+ and CD8+ subsets between responders and non-responders. GSTM1 and NOTCH2NLB were upregulated in the products from responders.
• The authors' conclusion: The authors concluded that the study showed the safety, efficacy and feasibility of mesothelin-targeting multiple-chain DAP CAR-T cells in patients with ovarian cancer and mesothelioma, and that the results point to directions for optimising next-generation KT032 cells
• Limitations the authors state:
  • Only eight patients were enrolled, and more patients are needed to verify safety and efficacy
  • Single-cell sequencing was done on samples from only three patients and needs verification in a larger cohort
  • Findings on the relation between efficacy and adverse immune events should be interpreted cautiously because of the small sample size
  • Persistence and tumour infiltration of the CAR-T cells were limited, and strategies to prolong persistence and trafficking are needed

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Ovarian cancer.

Medical terms in this study, explained in our Lexicon: CAR-T Cell, Mesothelin, Ovarian Cancer, Mesothelioma, Cytokine, Clinical Trial.

Related studies

• Affinity-tuned mesothelin CAR T cells demonstrate enhanced targeting specificity and reduced off-tumor toxicity — Y. Yang, Y. Vedvyas, et al. (2024)
• Membrane-bound TRAIL-armoring augments CAR-T cells in mesothelin-positive solid malignancies — A. Volpe, J. Zurita, et al. (2026)
• A novel mycobacterial Hsp70-containing fusion protein targeting mesothelin augments antitumor immunity and prolongs survival in murine models of ovarian cancer and mesothelioma — J. Yuan, S. Kashiwagi, et al. (2014)
• JNJ-79032421, a Novel Membrane-Restricted Mesothelin-Targeting T Cell-Engaging Bispecific Antibody for the Treatment of Mesothelin-Positive Cancers — K. Smans, T. Nesspor, et al. (2026)
• A human single-domain antibody elicits potent antitumor activity by targeting an epitope in mesothelin close to the cancer cell surface — Z. Tang, M. Feng, et al. (2013)
• Development of Highly Effective Anti-Mesothelin hYP218 Chimeric Antigen Receptor T Cells With Increased Tumor Infiltration and Persistence for Treating Solid Tumors — S. Tomar, J. Zhang, et al. (2022)

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