What are the long-term outcomes after plerixafor and G-CSF before stem cell transplantation?

This study investigated the long-term outcomes of patients with non-Hodgkin’s lymphoma (NHL) or multiple myeloma (MM) who received plerixafor (Mozobil) or placebo combined with G-CSF (granulocyte colony stimulating factor) before a stem cell transplant (SCT). This study concluded that adding plerixafor to G-CSF did not negatively impact the long-term survival of these patients.

High-dose chemotherapy followed with autologous hematopoietic stem cell transplantation (auto-HSCT) is the current treatment standard for relapsed or hard-to-treat NHL or MM. Auto-HSCT is needed after chemotherapy to restore the hematopoietic (blood-forming) cells in the bone marrow. To do the transplant, these cells need to be collected from the patient’s bloodstream. G-CSF is used to stimulate the production of stem cells. 

Plerixafor mobilizes blood-forming stem cells from the bone marrow into the bloodstream, where they can be collected for auto-HSCT. For patients who are “poor mobilizers,” plerixafor is another option. Whether combining plerixafor with a G-CSF leads to improved outcomes for NHL and MM patients is unclear.

This study involved 330 patients with NHL (167) or MM (163) at various stages of disease. 57% (NHL) and 82% (MM) of patients were in complete or partial remission.

74% (NHL) and 56% (MM) of patients received plerixafor with G-CSF. 26% (NHL) and 44% (MM) received placebo instead of plerixafor with G-CSF. 98% of NHL patients and all of the MM patients had SCT after completing the study treatment. The follow-up period was a total of 5 years.

The probability of achieving 5 year overall survival (OS; time from treatment until death from any cause) was 64% for NHL and MM patients who received plerixafor. The probability of OS was 56% (NHL) and 64% (MM) for patients who received placebo. These rates were not statistically significant.

The probaility of being progression-free at 5 years was 50% (NHL) and 17% (MM) for patients who received plerixafor. In patients who received placebo the probability of being progression free was 43% (NHL) and 30% (MM) for patients who received placebo. These were not statistically significant.

This study concluded that adding plerixafor to G-CSF did not have a negative impact on the long-term survival of patients with NHL or MM.

Because this study was observational, it only reported outcomes for enrolled patients. The study treatment (plerixafor or placebo given with G-CSF) was given to patients in two separate clinical trials. Only 58% of NHL patients and 55% of MM patients from the original clinical trials enrolled in the current study. The small sample size of this study also limits the chances of finding small differences between the two treatment groups.

Lastly, two of the authors were employed by Sanofi at the time of the study. Plerixafor is manufactured by Genzyme, a Sanofi company.