Anti-tumor activity of the MDM2-TP53 inhibitor BI-907828 in dedifferentiated liposarcoma patient-derived xenograft models harboring MDM2 amplification

• J. Cornillie ^[1] ; A. Wozniak ^[1] ; H. Li ^[1] ; Y. K. Gebreyohannes ^[1] ; J. Wellens ^[1] ; D. Hompes ^[2] ; M. Debiec-Rychter ^[3] ; R. Sciot ^[4] ; P. Schöffski ^[1]
  1. [1] Department of Oncology and Department of General Medical Oncology, Leuven Cancer Institute, KU Leuven and University Hospitals Leuven, Belgium
  2. [2] Department of Surgical Oncology, KU Leuven and University Hospitals Leuven, Belgium
  3. [3] Department of Human Genetics, KU Leuven and University Hospitals Leuven, Belgium
  4. [4] Department of Pathology, KU Leuven and University Hospitals Leuven, Belgium

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• Localización: Clinical & translational oncology, ISSN 1699-048X, Vol. 22, Nº. 4, 2020, págs. 546-554
• Idioma: inglés
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• Resumen

  • Purpose Dedifferentiated liposarcoma (DDLPS) is a soft tissue malignancy characterized by amplification of the mouse double minute 2 homolog (MDM2) gene. MDM2 is a negative regulator of tumor protein 53 (TP53). We tested the in vivo efficacy of BI-907828, a small molecule inhibitor of the MDM2-TP53 interaction, in two DDLPS patient-derived xenografts (PDX).

    Methods Partially immunodeficient mice were bilaterally engrafted with UZLX-STS3 (n = 24) and UZLX-STS5 (n = 24) human DDLPS tissue harboring MDM2 amplifications. Mice were grouped as follows: (a) vehicle (0.5% hydroxyethylcellullose) 10 ml/kg daily per os (p.o.); (b) doxorubicin 5 mg/kg weekly intraperitoneally (i.p.); (c) BI-907828 2.5 mg/kg daily p.o. and (d) BI-907828 10 mg/kg daily p.o. The treatment lasted for 15 days, all mice treated with BI-907828 were followed for 37 days post-treatment. Efficacy was assessed by tumor volume and histopathological evaluation.

    Results The 15-day treatment with 2.5 mg/kg and 10 mg/kg BI-907828 significantly inhibited tumor growth in UZLX-STS5 and -STS3 (p < 0.0001 compared to control for both models). All UZLX-STS5 and -STS3 tumors treated with BI-907828 decreased in size during treatment, and BI-907828-treated UZLX-STS5 tumors even disappeared completely. During the follow-up period, no tumor regrowth was observed in the UZLX-STS5 model and both doses of BI-907828 led to a pathological complete response, whereas a dose-dependent regrowth was seen in the UZLX-STS3 model.

    Conclusion BI-907828 showed significant anti-tumor activity in DDLPS PDX harboring MDM2 amplifications, providing a strong rationale for early clinical testing of BI-907828 in a DDLPS patient population.