Phase I/II Trial of Neoadjuvant Oregovomab-based Chemoimmunotherapy Followed by Stereotactic Body Radiotherapy and...

Cancer antigen (CA)-125 influences progression, metastasis, and outcomes in pancreatic cancer. This phase I/II trial (NCT01959672) evaluated the safety, efficacy, and immunologic correlates of chemoimmunotherapy (CIT) with oregovomab (anti-CA-125), followed by stereotactic body radiotherapy (SBRT) with the radiosensitizer nelfinavir.

Following imaging, pathologic confirmation, and staging laparoscopy, subjects received three 3-week cycles of CIT (gemcitabine/leucovorin/fluorouracil/oregovomab). Thereafter, nelfinavir was delivered (1250 mg bid) for 5 weeks, with SBRT (40 Gy/5 fractions) occurring during the third week of nelfinavir. Following another cycle of CIT, pancreaticoduodenectomy was performed if resectable. Three more cycles of CIT were then delivered (total 7 cycles). In subjects with high (≥10 U/mL) CA-125, oregovomab (2 mg) was administered for 7 total doses (3 pre-SBRT, 1 between SBRT and resection, and 3 postoperatively). The enzyme-linked immunospot assay evaluated the development of CA-125-specific CD8 T-lymphocytes.

The trial was prematurely closed because gemcitabine/leucovorin/fluorouracil was replaced by FOLFIRINOX and gemcitabine/nab-paclitaxel as the standard of care. Median follow-up was 13 months. Of 11 enrolled patients, 10 had high CA-125; 1 patient suffered an unexpected cardiac-related death, so 9 subjects received oregovomab. Ten received SBRT and 4 underwent resection. Overall, 6/11 patients experienced any grade ≥3 event. The median survival and time to progression were 13 and 8.6 months, respectively. Five patients had samples available for immunospot testing, of whom 2 (40%) developed CA-125-specific CD8 T-lymphocytes.

A combined pancreatic cancer multimodality approach using CIT and radiosensitized radiotherapy is feasible and safe; delivery of immunotherapy can lead to T-cell immunity. Re-evaluation with modern systemic paradigms is recommended.