Phase II study of the safety and efficacy of discontinuing pegfilgrastim for pancreatic adenocarcinoma treated with FOLFIRINOX

• Published in: Journal of clinical oncology Vol. 42; no. 3_suppl; p. 663
• Main Authors: Yanagi, Masahiro, Terashima, Takeshi, Yamashita, Tatsuya, Yamamoto, Makoto, Kido, Hidenori, Nakagawa, Hidetoshi, Seki, Akihiro, Nio, Kouki, Yamashita, Taro
• Format: Journal Article
• Language: English
• Published: 20.01.2024
• ISSN: 0732-183X; 1527-7755
• DOI: 10.1200/JCO.2024.42.3_suppl.663

663 Background: The original FOLFIRINOX regimen (5-fluorouracil, leucovorin, irinotecan, and oxaliplatin) for pancreatic ductal adenocarcinoma (PDAC) is associated with a high risk of febrile neutropenia (FN), and pegfilgrastim has been used to reduce the risk. However, it remains unclear how long pegfilgrastim needs to continue. This study evaluated the safety and efficacy of FOLFIRINOX after discontinuing pegfilgrastim in PDAC patients. Methods: This prospective phase II trial included patients with PDAC who received the first three courses of FOLFIRINOX, with primary pegfilgrastim prophylaxis for FN, and did not experience FN. The patients continued on FOLFIRINOX without pegfilgrastim from the fourth course. The primary endpoint was development of FN. The secondary endpoints included relative dose intensity (RDI), objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). The threshold and expected development of FN were 20% and 7%, respectively, at a one-sided significance level of 0.10 and statistical power of 80%. Based on this hypothesis, we calculated the number of patients needed to be 33. Results: In total, 34 patients (20 male, median age 66 years) were enrolled from August 2017 to September 2021. Twenty-three patients were unresectable, and 11 were borderline resectable. FN developed in one patient. Grade 4 neutropenia was observed in six patients, grade 3 neutropenia in 10 (29.4%), anemia in four (11.8%), diarrhea in two (5.9%), and malaise, lung infection, peripheral sensory neuropathy, colitis, and biliary tract infection in one (2.9%) each. Twenty-two patients required dose reduction, mainly because of neutropenia. Mean RDIs at the sixth course of oxaliplatin, irinotecan, leucovorin, acute infusion of fluorouracil, and continuous infusion of fluorouracil were 77.0%, 88.2%, 81.8%, 84.4%, and 87.6%, respectively. ORR, median PFS, and median OS were 44.1%, 15.8 months, and 25.8 months, respectively. Conclusions: FOLFIRINOX can be continued safely with a low incidence of FN after discontinuing pegfilgrastim in PDAC patients who did not experience FN during the first three courses of FOLFIRINOX, if the drug dose is reduced appropriately for neutropenia from the fourth course. Clinical trial information: UMIN000028055 .