Cyclophosphamide maintenance to extend combination chemotherapy-free interval in metastatic pancreatic ductal adenocarcinoma

Administering chemotherapy until progression to metastatic pancreatic ductal adenocarcinoma (PDAC) patients lacks of supporting evidence and causes cumulative toxicity. We explored the role of cyclophosphamide as maintenance therapy. PDAC germline BRCA1–2 wild-type patients who were progression-free after ≥6 months of any regimen and line of chemotherapy and received maintenance cyclophosphamide (mCTX) (50 mg/day), were included in the analysis. 42 patients were included in the analysis. Thirty-nine patients had progression of disease. Median PFS was 3.5 (range 1.0–31+) months. PFS rates at 6 and 12 months were 26.2% and 11.9%. At a median follow-up of 20.0 months (range 12.1–31.0 months), 20 patients died and 22 are alive. Median OS was 20.0 months (range 2.2–31.0+). OS at 6 and 12 months was 97.6% (95%CI: 93.4–100), and 73.8% (95% CI: 61.1–86.5), respectively. Only 2 patients receiving mCTX had Grade 3 toxicity. mCTX therapy yielded promising PFS and OS outcome in PDAC patients who were progression-free after induction chemotherapy, with unremarkable toxicity. Accordingly, this approach warrants further investigation.