Nplate May Increase Platelet Count During Vidaza Treatment For Myelodysplastic Syndromes
Published: Sep 14, 2010 1:55 pm
Results from a recent Phase 2 study suggest that Nplate may improve platelet counts in myelodysplastic syndromes patients during Vidaza treatment.
Nplate (romiplostim) mimics thrombopoietin, a protein that stimulates the production of platelets. Researchers hope that Nplate can be developed into an alternative for platelet transfusions, which can have side effects including allergic reaction and infection.
About 60 percent of patients treated with Vidaza (azacitadine) experience severely low platelet counts. Therefore, researchers wanted to study whether Nplate would raise platelet counts during Vidaza treatment.
The researchers divided 40 low- or intermediate-risk mydelodysplastic syndromes (MDS) patients into treatment groups receiving 500 µg Nplate, 750 µg Nplate, or placebo weekly during four 28-day cycles of Vidaza. The patients’ blood counts were monitored weekly. Given the small number of trial participants, all results are only descriptive.
Low-dose Nplate treatment increased platelet counts during the second treatment cycle, but the increase did not persist during the next two treatment cycles.
High-dose Nplate treatment increased platelet counts as soon as the first cycle of Vidaza treatment, with a significant increase during the third cycle.
After four cycles of treatment, 50 percent of patients on low-dose Nplate, 89 percent on high-dose Nplate, and 56 percent on placebo had a platelet response.
The risk of having a low platelet count (less than 50 x 109 platelets per liter of blood) from day 15 of the study onward was 62 percent for the group on low-dose Nplate, 71 percent for the group on high-dose Nplate, and 85 percent for the placebo group.
The proportion of low- and intermediate-1 risk patients who experienced low platelet counts (69 percent) was similar to that of intermediate-2 risk patients (76 percent).
The chance of needing a platelet transfusion during the study was 46 percent for the low-dose Nplate group, 36 percent for the high-dose Nplate group, and 69 percent for the group receiving the placebo. Low- and intermediate-1 risk patients had a lower platelet transfusion rate (38 percent) than intermediate-2 risk patients (86 percent). The proportion of patients requiring platelet transfusions decreased during the study.
Patients received anywhere from 0 to 72 units of platelets. However, for both the low-dose and high-dose Nplate groups, patients required a median of 0 units of platelets, compared to a median of 6 units of platelets for the placebo group.
Low platelet counts are typically correlated with faster progression of MDS to acute myeloid leukemia. Due to the low number of participants in the current study, it could not be determined whether Nplate delayed disease progression.
Nplate did not appear to affect Vidaza treatment, since each group had a similar response rate to Vidaza. Likewise, response to Vidaza did not appear to affect response to Nplate treatment, since rates of low platelet counts and transfusions were similar between those who did and those who did not response to Vidaza.
Side effects were mild and most commonly included diarrhea, extremity pain, dizziness, low blood pressure, and loss of appetite. Of the patients treated with Nplate, one experienced a severe rash. Severe bleeding events occurred in 2 placebo patients, 1 low-dose Nplate patient, and no high-dose Nplate patients.
Of the total participants, 68 percent completed the entire study. Adverse events not related to Nplate or placebo treatment caused 15 percent of patients to discontinue the study. Nplate treatment was stopped if platelet levels were too high (more than 450 x 109 platelets per liter of blood) and continued once they decreased (less than 200 x 109 platelets per liter of blood).
- Nplate May Be Safe For Lower-Risk MDS Patients (ASH 2012)
- Nplate Effective For Increasing Platelet Counts In Myelodysplastic Syndromes Patients (ASCO 2009)
- Clinical Trial Results Reveal Safety Issues With Nplate In Lower-Risk MDS Patients (ASH 2011)
- Researchers Determine Nplate Starting Dose For The Treatment Of Low Platelet Levels In MDS
- Nplate May Be Effective In Treating Thrombocytopenia In Myelodysplastic Syndromes Patients