Sequential gemcitabine (G), oxaliplatin (O), and irinotecan (I) based weekly metronomic chemotherapy (MC) regimens for the treatment of metastatic pancreatic cancer (mPC): A community cancer clinic experience.
284 Background: mPC has a poor prognosis with a median overall survival (mOS) ranging from 8.5 to 11.1 months (mo) with standard treatment, outlining the need for new innovative treatments. MC regimens utilize lower doses of chemotherapy that are administered more frequently which can maintain dose intensity while reducing toxicity. MC with paclitaxel (P) or nab-paclitaxel (N) may have effects on the tumor microenvironment. Methods: A retrospective analysis of treatment regimens and survival of patients (pts) with biopsy proven mPC who received treatment between August 2004 and August 2018 was performed. Results: 30 pts with biopsy proven mPC were identified. 14 pts received prior chemotherapy. mOS of this cohort was 18.9 mo after diagnosis and 14.2 mo after beginning MC. 70% of pts (21/30) survived longer than 12 mo, 37% (11/30) greater than 24 mo, and 27% (8/30) greater than 30 mo. All MC regimens were given on a weekly basis and included: P 60 mg/m² and G 600 mg/m² (PaG); P 60 mg/m², O 50 mg/m², folinic acid (L) 20 mg/m², and 5-fluorouracil (F) 425 mg/m² (POLF); P 60 mg/m², I 100 mg/m², and cisplatin (C) 20 mg/m² (PIC) or P 60 mg/m², I 100 mg/m², L 20 mg/m², and F 425 mg/m² (PILF). 21 pts received N instead of P at some point during their treatment. PaG, POLF, and PIC or PILF were purposely switched before disease progression after a median length of 13, 11 and 13 weeks respectively. 16 pts received PaG as their first regimen. 12 of these 16 pts then received POLF as their second regimen, and 7 of these 12 pts subsequently received PIC or PILF as their third regimen. These 7 pts had a mOS of 21.7 mo after diagnosis and 19.1 mo after beginning MC. 10 pts were successfully able to receive PaG, POLF, or PIC/PILF more than once. Conclusions: Weekly MC regimens such as PaG, POLF, and PIC/PILF that are given sequentially are an effective treatment for mPC. Switching regimens may prevent the development of chemotherapy resistance, allowing for chemotherapy regimens to be used again in the future. There are limitations of retrospective studies so further investigation of this treatment strategy should be done with a large randomized clinical trial.