Abstract 56P
Background
Between August 2021 and October 2022 7 patients were enrolled. Median age at diagnosis was 45 years (range 29 – 77). All patients enrolled had received at least 2 previous lines of systemic therapy. At a median follow-up of 66 months (range 45 – 256) median Pembro-PFS was 2.5 months (range 2 – 7). Median OS for metastatic disease was 46 months (15 – 125). Best treatment response was PD for 71% (5 pts) of patients enrolled; SD was achieved as the best treatment response only in 2 patients.
Methods
In this prospective non-randomized monocentric study, we enrolled 7 patients with metastatic sarcoma or GIST who failed standard therapies had at least one measurable lesion by RECIST 1.1. The primary endpoint of the study was Pembro-PFS. Secondary endpoints included OS and clinical benefit. Among 7 patients enrolled, 4 had a diagnosis of soft tissue sarcoma (1 pleomorphic rhabdomyosarcoma, 1 leiomyosarcoma, 1 extraskeletal mesenchymal chondrosarcoma, 1 epithelioid sarcoma) 1 bone sarcoma (chordoma) and 2 cKIT exon 11 GISTs. All patients were treated with pembrolizumab at 200 mg intravenously every 3 weeks until disease progression or inacceptable toxicity. For patients with GISTs, Pembrolizumab was associated with Imatinib 400mg orally per day. Imaging was performed at week 8 and every 12 weeks thereafter.
Results
Between August 2021 and October 2022 7 patients were enrolled. Median age at diagnosis was 45 years (range 29 – 77). All patients enrolled had received at least 2 previous lines of systemic therapy. At a median follow-up of 66 months (range 45 – 256) median Pembro-PFS was 2.5 months (range 2 – 7). Median OS for metastatic disease was 46 months (15 – 125). Best treatment response was PD for 71% (5 pts) of patients enrolled; SD was achieved as the best treatment response only in 2 patients.
Conclusions
Sarcomas are rare and aggressive neoplasms. The use of immunotherapy for all-comers did not show any benefit. Further studies on predictive biomarkes are needed to identify patients with a higher chance of response to immunotherapy.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.