What are the long-term outcomes for HL patients receiving plerixafor before a stem cell transplant?

This study compared the long-term outcomes of Hodgkin’s lymphoma (HL) patients who received plerixafor (Mozobil) to those who did not prior to autologous stem cell transplantation (autoSCT). This study concluded that plerixafor-treated patients had similar outcomes as patients who received conventional regimens.

High-dose chemotherapy followed by autologous stem cell transplantation (autoSCT) is the current standard for relapsed or hard-to-treat HL. Auto-SCT 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 (mobilization).

Conventional regimens include a G-CSF (granulocyte colony-stimulating factor) with or without chemotherapy. G-CSF increases stem cell production. Because many HL patients recommended for autoSCT have received many treatments already, the failure rates for stem cell collection are as high as 20 to 30%.

Plerixafor also mobilizes blood-forming stem cells from the bone marrow into the bloodstream, where they can be collected for autoSCT. For patients who are “poor mobilizers,” plerixafor is another option. However, the long-term effects of plerixafor after autoSCT compared to conventional regimens remain unclear.

This study involved 105 HL patients. Of these, 58% were in complete remission and 30.5% were in partial remission. All patients received either G-CSF only (4.76%) or G-CSF with chemotherapy (95.2%). 20% of patients also received plerixafor (plerixafor group). The remaining 80% did not receive plerixafor (control group). Patients were followed for an average of 24 months (plerixafor group) or 31 months (control group).

The plerixafor group had fewer cells collected over more collection days compared to the control group. On average, the plerixafor group required 5 days for stem cell collection compared to 2 days (control). This was statistically significant.

The amount of time needed for engraftment (blood cell levels restoring to normal) was comparable between both groups except for neutrophil (white blood cell) levels. The plerixafor group showed neutrophil engraftment over 11 days versus 10 days (control). This was statistically significant.

At 2 years, post-transplant, survival outcomes and relapse rates were not significantly different between the two groups. The overall survival (OS; time from treatment until death from any cause) rates were 85% (plerixafor) and 89% (control). The progression-free survival (PFS; time from treatment before disease progression) rates were 38% (plerixafor) and 55% (control). The relapse rates were 62% (plerixafor) and 44% (control).

This study concluded that plerixafor helped poorly mobilizing HL patients collect enough stem cells for autoSCT. These patients had similar outcomes after autoSCT compared to patients who mobilized well with conventional regimens.

This study looked back in time to analyze data. As a result, the collected data may be incomplete. The sample size of this study is also small, which may limit the conclusions that may be drawn. The average follow-up periods were also too small to detect late relapses or disease progression. More studies with larger patient populations and longer follow-ups are needed to confirm these results.

If you are an HL patient having difficulties with stem cell collection for autoSCT, talk to your care team about plerixafor.