Abstract 838
Background
The aim of this study is to compare the efficacy and safety of primary prophylaxis with once-per-cycle pegfilgrastim and intermittent every other day filgrastim in Korean patients with breast cancer treated with adjuvant docetaxel, doxorubicin, and cyclophosphamide (TAC) chemotherapy.
Methods
As a pilot study, patients who had undergone complete resection for breast cancer and scheduled to receive adjuvant TAC chemotherapy were enrolled in this study. Patients were randomized to receive a single injection of pegfilgrastim 6mg at Day 2 (D2) or intermittent 5 shots of filgrastim 5 mg/kg/day at D3, D5, D7, D9, and D11 as primary prophylaxis. Both prophylactic regimens were compared during the first 3 cycles of adjuvant chemotherapy. During the study period of adjuvant TAC chemotherapy, complete blood counts were collected on D1, D7, D9, and D14 of each cycle and routine physical examination was performed.
Results
Twenty-two patients were randomized. Eleven of 22 patients received pegfilgrastim, and the other 11 patients received intermittent filgrastim. Grade 4 neutropenia occurred in 11 of 11 patients (28 of 33 cycles) on intermittent filgrastim and 9 of 11 patients (18 of 33 cycles) on pegfilgrastim. Only one episode of febrile neutropenia was observed in 1 patient of pegfilfgrastim group.Table: 15P
Mean ANC during study period
| Mean ANC (SD) | |||
|---|---|---|---|
| Pegfilgrastim | Filgrastim | ||
| Cycle 1 | Day 1 | 3456 (428) | 3625 (314) |
| Day 7 | 271 (92) | 2143 (916) | |
| Day 9 | 1249 (316) | 1307 (451) | |
| Day 14 | 4747 (442) | 5555 (1023) | |
| Cycle 2 | Day 1 | 6178 (1024) | 6880 (1243) |
| Day 7 | 1495 (415) | 1590 (833) | |
| Day 9 | 1634 (368) | 1464 (845) | |
| Day 14 | 5785 (365) | 5876 (962) | |
| Cycle 3 | Day 1 | 6650 (767) | 6272 (1056) |
| Day 7 | 1598 (1003) | 2036 (731) | |
| Day 9* | 2694 (646) | 892 (411) | |
| Day 14 | 5773 (575) | 7343 (1371) |
Abbreviations: ANC, absolute neutrophil count; SD, standard deviation *P = 0.030
Conclusions
In this pilot study, there was no significant difference between two regimens of primary prophylaxis for febrile neutropenia in patients treated with adjuvant TAC chemotherapy. In case that the use of pegfilgrastim is limited, intermittent every other day 5-shots of filgrastim might be an alternative primary prophylaxis.
Editorial acknowledgement
Clinical trial identification
NCT02685111.
Legal entity responsible for the study
Sung-Bae Kim.
Funding
Kyowa Kirin Inc.
Disclosure
All authors have declared no conflicts of interest.