SBRT: 15 Gy x 1 on a single site of disease on day 1 cycle 1~Immunotherapy:~Nivolumab 3 mg/kg (up to 240 mg maximum) as i.v. infusion on day 1 (± 3 days) of each 14-day treatment cycle Ipilimumab 1 mg/kg as i.v. infusion on day 1 cycle 1 and subsequently every 6 weeks (± 3 days).~Vaccine (500 μl aqueous solution of 200 μg TGFβ-B-15 peptide mixed to an emulsion with 500μl Montanide ISA-51) as s.c. injection on day 1 of the first 6 cycles and subsequently every 4 weeks (± 3 days)
Non-immunogenicity of PC with high prevalence of immunosuppressive cells and typically a scarcity of tumor-infiltrating effector lymphocytes is considered as one of the reasons for lacking responsiveness to single-agent immunotherapies. Considering the emerging role of the tumor microenvironment, the combination of checkpoint blocking antibodies with immunomodulation of the tumor microenvironment could lead to better responses in tumor historically resistant to radiation and checkpoint blocking antibody approaches as single modalities. For example, the data from the phase 2 study CheckPAC (NCT02866383) showed durable clinical benefit in a small subgroup of patients after adding SBRT of 15 Gy to a combination of nivolumab and ipilimumab (presented at ASCO GI 2022, San Fransisco) in patients with resistant metastatic PC. Furthermore, we have found that the TGFβ-15 immune response is corelated to clinical benefit, supporting the rationale for combining of TGFβ-15 peptide vaccine with CheckPAC strategy (SBRT of 15 in combination with nivolumab and ipilimumab).