1518P - Stereotactic radiotherapy and IMM-101 in patients with oligometastatic pancreatic cancer following FOLFIRINOX: The MEPANC trial

Background

Pancreatic ductal adenocarcinoma (PDAC) patients with oligometastatic disease may benefit from additional multimodality treatment. By combining stereotactic beam radiotherapy (SBRT) on metastatic lesions with heat-killed mycobacterium (IMM-101) vaccinations, we hypothesized to induce the release of tumor antigens and boost the immune system for both a synergistic and abscopal effect.

Methods

This is an open-label, non-randomized, single centre safety run in to phase II study. We included oligometastatic PDAC patients, defined as ≤5 hepatic and/or pulmonary metastatic lesions with Ca-19 <1000 U/ml, with radiologically confirmed response or stable disease after FOLFIRINOX chemotherapy. Study treatment included 6 intradermal IMM-101 vaccinations combined with SBRT on the primary tumor and/or metastatic lesions. Monthly maintenance vaccinations were continued until progression or a maximum of 12 vaccinations. The primary endpoints included grade ≥3 adverse events (AE) and 1- year progression free-survival (PFS) rate from start FOLFIRINOX.

Results

Twenty-three patients are currently included in the study. Safety analysis was performed for twenty patients. The median follow up was 16.5 months (IQR 13.2 – 20.5) at the time of cut-off date. Eighteen patients successfully received all 6 vaccinations and two patients are currently being treated. Eight grade ≥ 3 AEs were observed. Six were unrelated. Two were possibly related to the study treatment; one grade 3 fever related to IMM-101 and one grade 4 post radiation pneumonitis related to SBRT. One year PFS rate was 75%, with a median PFS of 12 months (IQR 10.5 – 15.8). One year OS rate was 90%, with a median OS of 16.5 months (IQR 13.2 – 20.5).

Conclusions

Stereotactic beam radiotherapy combined with IMM-101 deemed to be safe and feasible in patients with oligometastatic PDAC and shows favourable preliminary progressive free survival outcomes. Additionally, immunomodulatory effects of the treatment on the peripheral blood will be analysed.

Clinical trial identification

NL74985.078.20.

Editorial acknowledgement

Legal entity responsible for the study

C. van Eijck.

Funding

Immodulon.

Disclosure

All authors have declared no conflicts of interest.