Abstract 762P
Background
Preclinical data shows that sustained, local delivery of low doses of GM-CSF by irradiated, genetically engineered tumor cells at the immunization site leads to specific, long-lasting anti-tumor immunity in several tumor types. Providing sustained levels of GM-CSF SC in a clinical setting remains challenging. Encapsulated Cell Technology enables the sustained and controlled delivery of GM-CSF by allogeneic cells. MVX-ONCO is an active, personalized cancer immunotherapy combining irradiated autologous tumor cells and encapsulated, genetically engineered allogeneic cells producing GM-CSF. Here we report the final results of the phase I clinical trial of MVX-ONCO in solid tumors.
Methods
34 pts were enrolled in a single-arm clinical trial (NCT02193503) evaluating the feasibility, safety and efficacy of MVX-ONCO. The treatment regimen consists of 6 doses over 8 weeks (W1,2,3,4,6,8). Each dose consists of 2 capsules containing allogeneic cells producing GM-CSF, co-implanted SC with irradiated autologous tumor cells in healthy skin; capsules are removed after 1 week. All pts received at least 1 dose of MVX-ONCO.
Results
All pts are evaluable for feasibility, safety, and efficacy. Compliant preparation of both irradiated autologous tumor cells and encapsulated MVX cells was achieved in 30/34 pts (88%). No pts experienced any treatment-related systemic toxicities. Local hematoma at the implantation site was reported in a minority of pts. Some degree of disease control was observed in 20/34 pts, including prolonged survival in 2/2 R/M HNSCC pts; one pt achieved a PR correlated with immunostimulatory signals (+ve IFN-y ELISpot) and the second pt is currently in CR with no antitumor therapy for >3 years. Monitoring of circulating T cell reactivity and DTH positivity correlates with >6 months survival.
Conclusions
MVX-ONCO is feasible, safe, and well-tolerated. Preliminary efficacy data shows immune stimulation, intriguing prolonged survival, and tumor control including PR and CR as BOR in 2/2 R/M HNSCC pts. Single-agent efficacy phase 2 study is ongoing in this population. Concurrent use of anti-PD1 and MVX-ONCO should be tested in a subsequent clinical trial.
Clinical trial identification
NCT02193503.
Editorial acknowledgement
Legal entity responsible for the study
Oncology Division at Geneva University Hospital (Geneva, Switzerland) and MaxiVAX SA (Geneva, Switzerland).
Funding
MaxiVAX SA.
Disclosure
J.N. Grogg: Financial Interests, Institutional, Full or part-time Employment: MaxiVAX. N. Mach: Financial Interests, Personal and Institutional, Stocks/Shares: MaxiVAX. All other authors have declared no conflicts of interest.