According to a recent study, omitting growth factor administration following stem cell transplantation results in fewer side effects and less and shorter hospitalization for multiple myeloma patients compared to those who do receive growth factors. In addition, the study authors found that there was little difference between the two groups in the repopulation of white blood cells following transplantation.

According to Dr. Morie Gertz, myeloma expert at the Mayo Clinic in Rochester, Minnesota and lead author of the study, the difference in the repopulation of white blood cells was not clinically significant. “None of the critically important end points were affected” he told The Myeloma Beacon.

Based on their results, Dr. Gertz and his colleagues concluded that the administration of growth factors is no longer necessary following stem cell transplantation.

“We just don’t see a role for it. It’s just another medicine that can cause a side effect, and I’m not sure what the benefit is,” he said. “They were using growth factors 25 to 30 years ago, at the start of transplants. Now things have changed, and I think it’s no longer necessary.”

Growth factor administration is the current standard of care for multiple myeloma patients who have undergone stem cell transplantation. Growth factors, such as Neupogen (filgrastim), are used to increase the production of white blood cells following transplantation.

The use of Neupogen after transplantation procedures was established by studies performed 20 years ago. Since that time, transplantation methods and technologies have changed considerably.

In early transplant procedures, stem cells were collected directly from the bone marrow. Currently, they are collected from the circulating blood by less invasive and more efficient procedures. In addition, the introduction of better antibiotic, antifungal and antiviral treatments has effectively prevented the emergence of infections following transplantation.

In addition to procedural changes that may eliminate the need for Neupogen, there are also several rare but serious side effects associated with its administration. These side effects include acute respiratory distress syndrome, allergic reactions, hemorrhage in the lung, and rupture of the spleen.

Despite transplantation procedural improvements and the serious risks associated with growth factor administration, recommendations made as recently as 2006 still support the use of growth factors in the transplantation setting.

In a previous study, researchers at the Mayo Clinic found that the elimination of growth factor administration after stem cell transplantation in amyloidosis patients resulted in very little difference in white blood cell recovery rate.

Based on these results, the researchers at the Mayo Clinic stopped administrating Neupogen to multiple myeloma patients after stem cell transplantation.

Their current study reports the comparison between myeloma patients with or without Neupogen as part of their supportive care following stem cell transplantation.

The researchers compared data of 498 patients who received Neupogen following transplantation to 166 patients who did not.

They found that white blood cells were repopulated in an average of 12.5 days following transplantation for patients who received Neupogen compared to 13.5 for those who did not. Optimal platelet levels were achieved in an average of 14.5 days for both groups.

Furthermore, 52 percent of patients who did not receive Neupogen were never hospitalized compared to 38 percent of patients who received Neupogen. Patients who did not receive Neupogen had an average hospital stay of zero days compared to 3.5 days for patients who received Neupogen.

According to Dr. Gertz, the most common causes of hospitalization were nutritional failure, weakness that inhibited the patients to come to the outpatient facility every day, and fever that could not be controlled with outpatient antibiotics.

Bacterial infection was also more common in the Neupogen-treated group, with 39 percent testing positive for bacteria compared to 27 percent in the untreated group.

The researchers noted that in addition to improving the safety of the transplantation procedure, the elimination of Neupogen would also result in substantial cost savings.

For more information, please see the research article in Bone Marrow Transplantation (abstract).