Evaluating busulfan plus melphalan conditioning for patients with multiple myeloma before stem cell transplantation

This study evaluated the safety and effectiveness of busulfan (Myleran) plus melphalan (Alkeran) compared to melphalan alone for patients with multiple myeloma (MM) before autologous stem cell transplantation (ASCT). This study concluded that the combination treatment was more effective for these patients.

Multiple myeloma is a type of cancer that can lead to abnormal immune cells. High-dose chemotherapy followed by ASCT is a key part of initial treatment. This type of chemotherapy is called a conditioning regimen. It is given before the transplant to get rid of any remaining cancer cells.

Melphalan is the most commonly used conditioning chemotherapy before ASCT. However, many patients have the cancer come back after the transplant (relapse). Alternative conditioning regimens may help prevent relapse for these patients. Whether busulfan plus melphalan is better than melphalan alone remains under investigation.

This study involved 202 patients with newly diagnosed MM. 104 patients were treated with busulfan and melphalan (combination group). 98 patients were treated with melphalan only. All patients then underwent ASCT. Patients were followed-up for an average of 20.2 to 22.6 months.

At 90 days after ASCT, 98% (combination group) and 97% (melphalan) of patients had tumor shrinkage or better.

Patients in the combination group had a significantly longer time without tumor growth or spread after treatment compared to patients treated with melphalan only (64.7 months vs. 43.5 months). Combined treatment with busulfan and melphalan was significantly associated with a 47% lower risk of tumor growth or spread.

Overall, similar numbers of patients between the combination group and the melphalan group were still alive 3 years later (91% vs. 89%). However, more patients in the combination group were alive 3 years later without tumor growth or spread (72% vs. 50%).

Overall, more patients in the combination group reported severe side effects compared to patients treated with melphalan only (84% vs. 33%). More patients in the combination group also reported mild to moderate mouth sores and pain (74% vs. 14%).

This study concluded that busulfan plus melphalan was safe and effective for patients with newly diagnosed MM before a stem cell transplant. The authors suggest that this combination may safely replace melphalan alone.

This study had a short follow-up period. More studies with longer follow-ups are needed to confirm these results. Studies investigating the combination of busulfan and melphalan for MM are ongoing.