Reduced dose pegfilgrastim is associated with less bone pain without increased neutropenia: a retrospective study

Background Chemotherapy for breast cancer is associated with a high risk of neutropenia. Pegfilgrastim reduces the risk of neutropenic fever but commonly causes bone pain. Objective Evaluate whether a reduced dose of pegfilgrastim (3 mg) reduced the frequency of bone pain without compromising efficacy. Methods Records reviewed from breast cancer patients who received at least one 3 mg dose of pegfilgrastim, white blood count (WBC), and absolute granulocyte counts (AGC) were collected. Musculoskeletal pain scale was collected at each visit. Results 265 treatments from 36 women were analyzed. There was no difference in post-treatment AGC between 3 versus 6 mg. Leukocytosis (WBC > 20,000 cells/cu mm) was more likely for those treated with 6 mg (chi-square 5.265, p = 0.0215). There was higher change in bone pain in patients who received 6 mg doses compared to none or 3 mg. Limitations In this retrospective, non-randomized study, we found the majority of patients received the reduced 3 mg dose after intolerance to the 6 mg dose. It is unknown if smaller or larger doses than 3 mg would achieve similar results or whether 3 mg dose would be effective as an initial therapy or for patients receiving different chemotherapy regimens. Pain is observed despite premedication with naproxen and/or loratidine. Conclusion Reduced dose of pegfilgrastim 3 mg was less likely to cause bone pain. The reduced dose was not associated with a significant difference in post-treatment AGC or rate of serious infection.