Abstract 2469
Background
Soft-tissue sarcomas (STS) are life-threatening diseases, for which more efficient therapeutic options are necessary. Trabectedin (T) is an anti-tumor drug approved for the treatment of advanced STS. Synergistic drug combinations could improve T results in STS patients. Rapamycin (R) is an mTOR pathway inhibitor. Synergy with T has been described in ovary clear cell carcinoma. Of note, R suppresses DNA double-strand breaks repair, thus generating the perfect set-up for T activity. Altogether, we hypothesize that T+R combination (T+R) is synergistic in STS, and that mTOR inhibition enhances T activity.
Methods
Human STS cell lines (n = 9) were treated with increasing doses of T (1x10-7M to 1x10-11M) and/ or R (1x10-9 to 1x10-11) to determine IC50 and combination index (CI) values. Cells were initially exposed to R, 2 hours later T was added, under the assumption that R pre-treatment favors T cytotoxicity. Cell viability, at 72 h, was measured by MTS assay. Apoptosis was determined by Western Blot for PARP and Caspase 3 cleavage. In vivo experiments were performed in immunocompetent 3-methylcolanthrene fibrosarcoma mice: T was administrated via IV (0.15 mg/kg; q7dx1) and R via IP (0.50 mg/kg; q7dx2). Body weight and tumor volume were measured every 2 days for 15 days of treatment. Tumors were collected for analysis (snap frozen and paraffin embedding).
Results
T+R was synergistic in all STS cell lines: CP0024 primary leiomyosarcoma and 93T449 liposarcoma cell lines showed strong synergism with CI at the ED50 of 0.129 and 0.027, respectively. This synergy was followed by an increase of PARP and Caspase 3 cleavage. The synergism was confirmed in vivo: mice treated with R+T showed tumor growth delay in comparison to the drugs alone (p < 0.05). Stable disease was achieved in 7 out of 7 mice.
Conclusions
R+T is synergic in STS and deserves exploration in clinical setting. Further research will reveal the mechanisms underlying this synergy.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Javier Martín Broto.
Funding
PharmaMar.
Disclosure
D.S. Moura: Research grant / Funding (institution): PharmaMar; Research grant / Funding (institution): Eisai; Research grant / Funding (institution): Novartis; Travel / Accommodation / Expenses: PharmaMar; Travel / Accommodation / Expenses: Eisai. M. Lopez-Alvarez: Travel / Accommodation / Expenses: Eisai. N. Hindi: Travel / Accommodation / Expenses: PharmaMar; Research grant / Funding (institution): Eisai; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): PharmaMar; Honoraria (self): PharmaMar. J. Martin-Broto: Research grant / Funding (institution): PharmaMar; Research grant / Funding (institution): Eisai; Research grant / Funding (institution): Novartis; Honoraria (self): PharmaMar; Honoraria (self): Lilly; Honoraria (self): Novartis; Speaker Bureau / Expert testimony: PharmaMar. All other authors have declared no conflicts of interest.
Resources from the same session
3620 - Safety, efficacy, PK and PD biomarker results of the first-in-human study of mutant isocitrate dehydrogenase 1 (mIDH1) inhibitor BAY 1436032 in patients (pts) with mIDH1 advanced solid tumours
Presenter: Wolfgang Wick
Session: Poster Display session 1
Resources:
Abstract
5465 - Proof of concept clinical study by US-guided intratumor injection of VCN-01, an oncolytic adenovirus expressing hyaluronidase in patients with pancreatic cancer
Presenter: Manuel Hidalgo
Session: Poster Display session 1
Resources:
Abstract
2555 - A Phase 1a/b first-in-human, open-label, dose-escalation, safety, PK and PD study of TP-0903 in solid tumors
Presenter: John Sarantopoulos
Session: Poster Display session 1
Resources:
Abstract
3533 - First in human phase 1/2a study of PEN-866, a Heat Shock Protein 90 (HSP90) ligand – SN38 conjugate for patients with advanced solid tumors: Phase 1 results
Presenter: Johanna Bendell
Session: Poster Display session 1
Resources:
Abstract
4114 - A Phase I Open-Label, Non-Randomized Study of Recombinant Super-Compound Interferon (rSIFN-co) In Patients with Advanced Solid Tumors
Presenter: Amanda Seet
Session: Poster Display session 1
Resources:
Abstract
2537 - Evaluation of Pharmacodynamic (PD) Biomarkers in Advanced Cancer Patients Treated with Oxidative Phosphorylation (OXPHOS) Inhibitor, OPC-317 (OPC)
Presenter: Jie Qing Eu
Session: Poster Display session 1
Resources:
Abstract
5764 - Pharmacokinetic (PK) assessment of BT1718: A phase 1/2a study of BT1718, a first in class Bicycle Toxin Conjugate (BTC), in patients (pts) with advanced solid tumours
Presenter: Natalie Cook
Session: Poster Display session 1
Resources:
Abstract
2683 - A phase I open label dose escalation trial evaluating VT1021 in patients with advanced solid tumors.
Presenter: Wael Harb
Session: Poster Display session 1
Resources:
Abstract
3609 - Interim Results from Trial of SL-801, a Novel XPO-1 Inhibitor, in Patients with Advanced Solid Tumors
Presenter: Judy Wang
Session: Poster Display session 1
Resources:
Abstract
3485 - Phase 1 Trial of Fruquintinib in Patients with Advanced Solid Tumors: Results of the Dose Escalation Phase
Presenter: Andrea Wang-Gillam
Session: Poster Display session 1
Resources:
Abstract