Patients with metastatic or relapsed pediatric sarcomas receive cytotoxic regimens that induce high remission rates associated with profound lymphocyte depletion, but ultimately few survive long term. We administered adjuvant immunotherapy to patients with metastatic and recurrent pediatric sarcomas in an effort to improve outcomes.
Patients newly diagnosed metastatic or recurrent pediatric sarcoma. Patients with Ewing Sarcoma, Rhabdomyosarcoma, Desmoplastic small round cell sarcoma (DSRCT), Synovial sarcoma and undifferentiated sarcoma.
• Monocytes were cryopreserved and to manufacture each DC dose, two aliquots of 100e6 of monocytes were thawed and cultured with GM-CSF, IL-4, IFN-y and clinical grade lipopolysaccharide
• One DC aliquots was pulsed with autologous tumor lysate and a second pulsed with KLH then they were combined at 1:1 ratio to comprise each DC vaccine.
6 DC vaccines were injected (3 Subcutaneously (SC) 1×107 cells/site and 3 Intradermally (ID)sites 1×106 cells/site.rhIL-7 was administered Subcutaneously (SC) on days 0, 14 ± 7d, 28 ± 7d and 42 ± 7d.
• No grade 3 or 4 adverse events were attributed to all patients.
• Grade 2 injection site reactions attributable to the DC vaccines occurred in 17% of patients.
• Transaminitis in 31% of patients, grade 4 fever and grade 4 anaphylaxis were attributed to CYT107 (rlIL-7).
• All toxicities were fully reversible.
• Intent-to-treat analysis of all patients enrolled demonstrates 5-year overall survival (OS) of 51% and PFS of 32% (median potential 59 months range 43-88 months).
• Patients with Ewing sarcoma and Rhabdomyosarcoma experiencing improved outcomes 5-year OS 63% and PFS 40%.
• Five-year intent- to-treat OS of patients with newly diagnosed metastatic Ewing/rhabdomyosarcoma was 77%.
• T-cell responses to autologous tumor lysate were identified in 62% of immunotherapy recipients, and survival was higher in those patients (73% 5-year OS with vs. 37% without immune response).
• 25 of 35 patients with ES and Rhabdomyosarcoma showed no evidence of disease.
This study present promising clinical outcomes in high-risk patients with ES and Rhabdomyosarcoma following administration of non-toxic, outpatient adjuvant immunotherapy regimen administered following standard therapy. Adjuvant immunotherapy may improve survival in patients with metastatic pediatric sarcoma.