Results of a recent small German study show that stem cell transplanta­tion as salvage therapy is most effective in patients who had a long remission duration after a previous transplant.

Specifically, results of the study show that patients who relapsed 12 months or later after their last transplant had significantly longer progression-free and overall survival times after salvage transplantation than patients who relapsed within 12 months. 

According to the study authors, patients who relapse within 12 months of a previous transplant do not benefit from this form of salvage therapy.

Based on these findings, the study authors recommended that patients who relapse early after receiving a stem cell transplant receive other forms of salvage therapy such as combination therapies including Revlimid (lenalidomide), thalidomide (Thalomid), and Velcade (bortezomib) or treatments that are being investigated in clinical trials.

Dr. Leona Holmberg of the Fred Hutchinson Cancer Research Center in Seattle, who was not involved in the study, agreed that patients who relapse early after transplantation should be given alternative forms of salvage therapy.

“[These patients] do not benefit much from salvage autologous stem cell transplant, so it’s reasonable to try non-transplant clinical trials,” Dr. Holmberg told The Myeloma Beacon. 

High-dose chemotherapy followed by autologous stem cell transplantation is a standard of care for myeloma patients who are able to tolerate the treatment.

Although stem cell transplantation may increase overall survival for myeloma patients, especially those who achieve a complete response, most patients eventually relapse and require salvage therapies to bring their disease back into remission.

A past study has shown that, when used as salvages therapies, Revlimid, thalidomide, and Velcade improve overall survival in patients who relapse early after stem cell transplantation (see related Beacon news).

According to the study authors, however, there are limited data available on the efficacy of stem cell transplantation as salvage therapy for myeloma patients.

In order to better understand the role of salvage stem cell transplantation, researchers from the Heinrich-Heine University in Duesseldorf, Germany, analyzed medical records from 55 myeloma patients treated with a salvage stem cell transplant at their institution.

Of the 55 patients included in the analysis, 76 percent received a single stem cell transplant and 24 percent of patients received two back-to-back stem cell transplants as initial therapy.

Following initial treatment, patients had a median remission time of 23 months. The median time between relapse and salvage stem cell transplantation was five months.

As a preparative regimen prior to salvage transplantation, 27 percent of patients received 200 mg/m² of melphalan (Alkeran), 33 percent received 140 mg/m² of melphalan plus 12 mg/kg of busulfan (Busulfex), and 40 percent received 200 mg/m² of melphalan plus 1.3 mg/m² of Velcade.

Following salvage stem cell transplantation, 9 percent of patients achieved a complete response, 9 percent achieved a very good partial response, and 56 percent achieved a partial response.

At a median follow-up of 19 months after salvage transplantation, the median progression-free survival time was 14 months and the median overall survival time was 52 months.

The study authors found no significant difference in response, progression-free survival, or overall survival among patients based on the conditioning regimens.

However, they found that patients who relapsed early after their initial stem cell transplant had significantly shorter progression-free and overall survival times.

Patients who relapsed within 12 months of their initial transplant had a progression-free survival time of four months and an overall survival time of seven months, compared to 15 months and 40 months, respectively, for patients who relapsed between 13 and 24 months following their initial transplant.

Patients who relapsed between 25 and 36 months following their initial transplant had the longest progression-free and overall survival times (15 months and 78 months, respectively).

Of the 55 patients included in the analysis, 11 percent experienced kidney toxicity, 9 percent experienced cardiac toxicity, and 2 percent experienced liver toxicity.

Five percent of patients died from treatment-related complications during the first 100 days following salvage stem cell transplantation.

For more information, please see the article in Leukemia & Lymphoma (abstract).