Study Compares Filgrastim vs Tbo-Filgrastim in Patients With Myeloma

A new hospital-wide formulary change resulted in the replacement of filgrastim with tbo-filgrastim for all on- and off-label indications. A new study comparing the duration of neutropenia in patients after autologous hematopoietic stem cell transplantation (HSCT) finds that there are no significant differences in the results between filgrastim and tbo-filgrastim in a clinical setting. However, tbo-filgrastim offers significant cost savings over filgrastim.

Study Methods

Filgrastim, a bone marrow stimulant, helps the body make white blood cells after receiving cancer medications. It can also improve survival in people who have been exposed to radiation. While neutropenia is an abnormally low count of a type of white blood cell, myeloma is a type of cancer that originates in the bone marrow.

Steven Trifilio, along with his fellow researchers, used data from the Northwestern Memorial Hospital electronic database and published the findings in Clinical Transplantation: The Journal of Clinical and Translational Research. They studied 182 patients with myeloma. Out of these, 91 patients had received filgrastim immediately prior to the change and 91 had received tbo-filgrastim afterward. Most patients from both groups received chemotherapy three weeks prior to transplantation.

Results

Several demographic characteristics such as age, weight, gender, body surface, number of doses per patient, stem cell doses, etc, were studied among patients who received either tbo-filgrastim or filgrastim following stem cell infusion. There was no significant difference in platelet count at the time of engraftment (Engraftment is when the new blood-forming cells start to grow and make healthy blood stem cells that show up in your blood; it is an important milestone in transplant recovery)

Although overall time to stem cell engraftment was similar for both groups, early engraftment occurred more often in filgrastim-treated patients. Conversely, documented infections were observed more frequently in tbo-treated patients vs filgrastim-treated patients.

Conclusion

Early studies using filgrastim in patients with myeloma treated with autologous HSCT showed lesser duration of neutropenia by as much as 2 weeks. However, filgrastim is expensive. And since transplant recipients typically receive more therapy, some cost saving alternatives could be realized with less-expensive agents. This enables healthcare officials to provide efficacy and safety all at a reduced cost.

The study shows that tbo-filgrastim is about the same as filgrastim with respect to safety and efficacy. However, the cost-saving potential is manifold in using tbo-filgrastim over filgrastim. For every 480 lm vial, the current cost of tbo-filgrastim is $286.80 as compared to filgrastim that costs $356.39.

With almost 25% difference between the 2, patients who require 9 tbo-doses versus 8 filgrastim doses would still promote significant cost savings (approximately $400 per patient). Simultaneously, the median length of stay at the hospital was also similar for both study groups.

“Tbo-filgrastim and filgrastim differ in time to engraftment and rates of infection following autologous stem cell transplantation. Whether these results are clinically relevant or significantly impact cost savings remains to be determined in future randomized studies,” the study stated.