1363 - Trabectedin with concurrent low-dose of radiation therapy for metastatic soft tissue sarcomas: A phase II trial of Spanish, French and Italian sarcoma groups

Background

The capacity of inducing tumor shrinkage in advanced soft tissue sarcomas (STS) is an unmet need beyond the first-line of systemic therapy. Pivotal studies of approved drugs reported RECIST response rates below 10%. Thus, it is challenging to relieve symptoms related to tumor volume in patients progressing to anthracycline-based schemes. Besides that, the overall response rate (ORR) is an appropriate surrogate for overall survival. This phase II trial explores the combination of trabectedin (T) and concurrent radiotherapy (RT) in the metastatic setting and is supported by preclinical experiments and previous phase I trial.

Methods

Patients received T 1.5 mg/m² in 24-h infusion and started RT (30 Gy, 3 Gy/day) from the end of the first T perfusion. Most relevant inclusion criteria were metastatic progressing STS, a maximum of two previous systemic lines for advanced disease with at least one previous anthracycline-based line. Neither all the lesions nor all the sites were required to be irradiated. The main endpoint was ORR by RECIST 1.1. A Simon 2-stage was used to estimate 35% ORR of interest for further investigation (α = 0.1, power 90%; P0 = 0.10). Central pathology and radiological review were mandatory.

Results

From 10/2017 to 11/2018, 27 patients were enrolled. Histologies were: leiomyosarcoma 7 (26%), synovial sarcoma 6 (22%), liposarcoma 4 (15%) and other 10 (37%). The median of previous lines was 2, and ECOG distribution was 0: 19 (70%) and 1: 8 (30%). With a median follow-up of 6 months (1-12), there were 9 events of progression and 3 events of death. The 6-month PFSR was 75% and the 6-month OSR was 86%. From 26 evaluable patients by RECIST, there were 15 PR (57.7%), 7 SD (26.9%) and 4 PD (15.4%). One G3 and 3 G1 pneumonitis were observed. One toxic death occurred (sepsis) being G3-4 neutropenia observed of 7 (26%) while febrile neutropenia was reported in 2 (7.4%) cases.

Conclusions

T concurrent with RT showed a relevant activity in progressing metastatic setting in a wide range of STS types, giving options for tumor shrinkage beyond the first-line of advanced STS. The RECIST ORR of 57.7% and 6-m PFSR of 75% confirm the synergy of T+RT.

Clinical trial identification

NCT02275286.

Editorial acknowledgement

Legal entity responsible for the study

GEIS (Spanish Group for Research on Sarcoma).

Funding

GEIS, ISG (Italian Sarcoma Group), FSG (French Sarcoma Group); PharmaMar.

Disclosure

J. Martin Broto: Research grant / Funding (institution): EISAI; Research grant / Funding (institution): Novartis; Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: PharmaMar; Advisory / Consultancy: Lilly. A. Italiano: Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Roche; Honoraria (self), Advisory / Consultancy: Daiichi Sankyo; Advisory / Consultancy: Inmune Design; Honoraria (self), Advisory / Consultancy: Epizyme; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Bayer; Honoraria (self), Advisory / Consultancy: Lilly; Honoraria (self): Novartis; Research grant / Funding (self): Merck Serono; Research grant / Funding (self): AstraZeneca/MedImmune; Research grant / Funding (self): MSD Oncology. R.M. Alvarez Alvarez: Honoraria (self), Advisory / Consultancy, Research grant / Funding (self), Travel / Accommodation / Expenses: PharmaMar; Advisory / Consultancy: Lilly; Honoraria (self), Advisory / Consultancy: Boehringer Ingelheim; Research grant / Funding (self), Travel / Accommodation / Expenses: Roche; Honoraria (self): Pierre Fabre; Honoraria (self): Pfizer; Honoraria (self), Research grant / Funding (institution): Novartis; Honoraria (self): Bayer; Honoraria (self): Bristol-Myers Squibb; Research grant / Funding (self): Roche; Research grant / Funding (self): AstraZeneca; Research grant / Funding (self): Peregrine Pharmaceuticals; Research grant / Funding (self): AbbVie; Research grant / Funding (self): Merrimack; Research grant / Funding (institution): Janssen. A. Lopez Pousa: Travel / Accommodation / Expenses: PharmaMar. A. Redondo: Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: Roche; Advisory / Consultancy, Travel / Accommodation / Expenses: AstraZeneca; Advisory / Consultancy: Tesaro; Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: PharmaMar; Advisory / Consultancy: Clovis Oncology; Research grant / Funding (institution): Eisai. J. Blay: Honoraria (self), Research grant / Funding (self): PharmaMar. A. Gronchi: Honoraria (self), Advisory / Consultancy: Novartis; Advisory / Consultancy: Bayer; Honoraria (self), Advisory / Consultancy: Lilly; Advisory / Consultancy, Travel / Accommodation / Expenses: Nanobiotix; Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: PharmaMar; Honoraria (self): Pfizer. N. Hindi: Honoraria (self), Research grant / Funding (institution), Travel / Accommodation / Expenses: PharmaMar; Research grant / Funding (institution): Eisai; Research grant / Funding (institution): Novartis. All other authors have declared no conflicts of interest.