1718PA prospective correlative trial of personalized patient-derived xenograft (PDX) as avatars for drug therapy in patients with metastatic or recurrent soft tissue sarcomas (STS)

Abstract Background The overall benefit from systemic treatments in advanced STS remains modest despite advances in cancer therapies. PDX models may help as avatars in guiding individualized drug use decisions. Methods In this prospective single center trial, fresh tumors from patients (pts) with suspected or recently diagnosed STS were engrafted into immunodeficient mice avatars (TumorGraft; Champions Oncology) and tested against a number of standard or non-licensed agents. PDX drug sensitivity profiles were then compared with real-life treatment outcomes. Results Of 18 patients enrolled, 3 patients were excluded (consent withdrawal/non-sarcomas). Patient baseline characteristics are summarized in the table. Rate of engraftment was 40% (6/15 pts), while the median time from biopsy to availability of drug sensitivity profile was 379 days (186 – 421). In patients with available drug sensitivity profile (9 different drugs involving 6 pts), the mouse avatar correctly predicted the drug efficacy or lack thereof of drugs in 7 of 9 drug selection time-points (78%) and in 5 of 6 patients (83%). Table . 1718P Patient baseline characteristics Item Eligible patients (n = 15) Engrafted patients (n = 6) Median age (range) 57 (23-76) 57 (45-69) Gender (M:F) 8:7 3:3 Subtype - Liposarcoma - Leiomyosarcoma -UPS -Others 5 3 1 6 2 2 1 1 Conclusions PDX avatars can accurately predict drug response in STS pts. The rate of engraftment and time taken to produce drug sensitivity profiles are limitations for using this platform in guiding treatment for individual patients in real time. Nonetheless, the high degree of clinical predictability of this PDX platform may offer therapeutic value for personalized oncology approaches. Legal entity responsible for the study Albiruni Razak. Funding Mount Sinai Sarcoma Foundation. Disclosure G. Paris: Full / Part-time employment: champions oncology. M. Mancini: Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options, Full / Part-time employment: Champions Oncology. A.R.R. Albiruni: Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Boehringer Ingelheim; Advisory / Consultancy, Research grant / Funding (self): Lilly; Advisory / Consultancy, Research grant / Funding (self): Merck; Research grant / Funding (self): CASI Pharmaceuticals; Research grant / Funding (self): Novartis; Research grant / Funding (self): Deciphera; Research grant / Funding (self): Kayopharm Therapeutics; Research grant / Funding (self): Pfizer; Research grant / Funding (self): Roche/ Genentech; Research grant / Funding (self): Boston Biomedical; Research grant / Funding (self): Bristol-Myers Squibb; Research grant / Funding (self): MedImmune; Research grant / Funding (self): Amgen; Research grant / Funding (self): GlaxoSmithKline; Research grant / Funding (self): Blueprint Medicines; Research grant / Funding (self): AbbVie; Research grant / Funding (self): Adaptimmune. All other authors have declared no conflicts of interest.