Safety and efficacy of PEG-rhG-CSF as primary prophylaxis against neutropenia induced by combination chemotherapy regimens involving oral chemotherapy agents in gastrointestinal cancer patients: A prospective, exploratory, non-randomized controlled study.

e24107 Background: The safety and efficacy of PEGylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) for prevention of chemotherapy-induced neutropenia (CIN) in patients undergoing oral chemotherapy remain unclear. This study investigated the safety and efficacy of PEG-rhG-CSF as primary prophylaxis against CIN in gastrointestinal (GI) cancer patients receiving combination chemotherapy regimens involving oral chemotherapy agents. Methods: This is a prospective, single-center, open-label, exploratory, non-randomized controlled study. GI cancer patients receiving two consecutive cycles of IV oxaliplatin (150mg/m 2 on day 1) combined with oral capecitabine 1000mg/m 2 or tegafur gimeracil oteracil potassium capsule 40-60mg twice daily on days 1-14 every 3 weeks. PEG-rhG-CSF (6mg) was administered subcutaneously 24 hours post-oxaliplatin treatment in the PEG-rhG-CSF group, while the control group did not receive it. The primary endpoint was safety, and secondary endpoints included CIN incidence and neutropenic complications. The study was registered with the Chinese Clinical Trial Registry (registration number ChiCTR2100054854). Results: Between March 2022 and January 2023, a total of 49 patients was screened, and 43 patients completed the treatment (26 in PEG-rhG-CSF group and 17 in control group). The average age was 61.4 years, with 90.7% males and 83.7% having gastric cancer. Baseline characteristics were similar between the two groups. The overall adverse events (AE) did not differ statistically (88.5% vs. 88.2%, p = 1.000), with grade £2 fatigue and nausea being the most common AEs. Grade 3 platelet reduction showed no significant difference between the two groups (7.69% vs. 17.65%, p = 0.432). Four cases of bone pain (15.4%) and five cases of injection site reactions below grade 3 (19.2%) were observed in the PEG-rhG-CSF group. Grade ≥2 CIN was significantly lower in the PEG-rhG-CSF group (3.84% vs. 58.82%, p < 0.001). One case in the PEG-rhG-CSF group required antibiotic treatment due to febrile neutropenia. Regarding neutropenic complications, the PEG-rhG-CSF group exhibited lower proportion of chemotherapy delay (3.85% vs. 35.29%, p < 0.001) and dose reduction (1.92% vs. 23.53%, p = 0.002). Rescue treatment with rhG-CSF for grade 3/4 CIN was significantly less frequent in the PEG-rhG-CSF group (1.92% vs. 23.53%, p = 0.002). Conclusions: Primary prophylaxis with PEG-rhG-CSF in GI cancer patients undergoing oral capecitabine/tegafur gimeracil oteracil potassium may be safe, without an increased chemotherapy-related AEs, and is associated with a reduced grade ≥2 CIN. Clinical trial information: ChiCTR2100054854.