Pegfilgrastim Versus Filgrastim To Accelerate Hematopoietic Recovery after High Dose Melphalan and Autologous Hematopoietic Stem Cell Transplant (ASCT) for Multiple Myeloma.

High-dose melphalan followed by ASCT is a common component of the early treatment for patients with multiple myeloma. Daily subcutaneous injections of filgrastim (Neupogen) at 5 ug/kg/day until ANC > 500/ul are routinely administered at our center from day +4 following ASCT, in order to accelerate hematopoietic recovery and lessen neutropenic complications. Pegfilgrastim (Neulasta) as a single 6 mg fixed dose subcutaneous injection has been shown to have similar efficacy and ease of use when compared to filgrastim in the non-transplant setting, but little data is available in the transplant setting. We began using pegfilgrastim day +1 following ASCT for patients with multiple myeloma and performed a retrospective cohort study comparing those who received filgrastim (n=6) with those who received pegfilgrastim (n=11). Transplants occurred between July 2002 and January 2004 and included all patients transplanted for myeloma in that time period for whom sufficient data was available. All patients had at least 2 x 10⁶ CD34+ cells/kg peripheral stem cells harvested after cytoxan and filgrastim mobilization. Main outcome measures were: days from stem cell infusion to WBC nadir, days to ANC>500/ul, and days to ANC>1000/ul. Subjects were excluded if CBCs were drawn less frequently than every four days. There were no significant differences between the filgrastim and pegfilgrastim groups with respect to the following demographic variables: age, gender, hemoglobin, creatinine, calcium, albumin and beta-2 microglobulin at diagnosis. The groups were also balanced with respect to SPEP, UPEP, presence of lytic lesions and number of prior lines of therapy. The median number of CD34+ cells infused was similar: 5.7 x 10⁶ in the filgrastim group vs 4.8 x 10⁶ in the pegfilgrastim group (p=0.28). After transplant, median number of days to WBC nadir in the filgrastim group (FG) was 7 (range 5–9) vs 6 (range 5–8) in the pegfilgrastim group (PG) (p=0.31). However, median number of days to ANC>500/ul in the FG was 11.5 (range 11–17) vs 10 (range 9–12) for PG (p=0.02). Similarly, median number of days to ANC>1000/ul was 12 (range 11–17) for FG vs 11 (range 10–13) for PG (p=0.03). Five of six patients in the FG had neutropenic fever after transplant, compared to five of eleven patients in the PG (p=0.30). Currently, no significant differences in infection or relapse rates between groups have been noted and there were no deaths in either group. In this retrospective cohort study, pegfilgrastim was safe and at least equivalent to filgrastim for accelerating hematopoiesis after ASCT for multiple myeloma. Furthermore, there was no significant difference in the incidence of neutropenic fever, infection and survival, suggesting a similar clinical utility.