The Effect of Radiation Dose and Variation in Neupogen® Initiation Schedule on the Mitigation of Myelosuppression during the Concomitant GI-ARS and H-ARS in a Nonhuman Primate Model of High-dose Exposure with Marrow Sparing. Issue 5 (November 2015)

• Record Type: Journal Article
• Authors: MacVittie, Thomas J.; Bennett, Alexander W.; Farese, Ann M.; Taylor-Howell, Cheryl; Smith, Cassandra P.; Gibbs, Allison M.; Prado, Karl; Jackson, William
• Is Part Of: Health physics. Volume 109:Issue 5(2015:Nov.)
• Publication Date: 2015-11
• Subjects: laboratory animals -- modeling, biological factors -- mortality -- radiation damage; Biophysics -- Periodicals; Health Physics -- periodicals; Radiation Protection -- periodicals; Radiotherapy -- periodicals; Medische fysica; Electronic journals; 612.01448
• DOI: 10.1097/HP.0000000000000350
• Languages: English
• ISSNs: 0017-9078

Abstract

Abstract : Abstract: A nonhuman primate (NHP) model of acute high-dose, partial-body irradiation with 5% bone marrow (PBI/BM5) sparing was used to assess the effect of Neupogen® [granulocyte colony stimulating factor (G-CSF)] to mitigate the associated myelosuppression when administered at an increasing interval between exposure and initiation of treatment. A secondary objective was to assess the effect of Neupogen® on the mortality or morbidity of the hematopoietic (H)- acute radiation syndrome (ARS) and concurrent acute gastrointestinal radiation syndrome (GI-ARS). NHP were exposed to 10.0 or 11.0 Gy with 6 MV LINAC-derived photons at approximately 0.80 Gy min −1 . All NHP received medical management. NHP were dosed daily with control article (5% dextrose in water) initiated on day 1 post-exposure or Neupogen® (10 μg kg −1 ) initiated on day 1, day 3, or day 5 until recovery [absolute neutrophil count (ANC) ≥ 1, 000 cells μL −1 for three consecutive days]. Mortality in both the 10.0 Gy and 11.0 Gy cohorts suggested that early administration of Neupogen® at day 1 post exposure may affect acute GI-ARS mortality, while Neupogen® appeared to mitigate mortality due to the H-ARS. However, the study was not powered to detect statistically significant differences in survival. The ability of Neupogen® to stimulate granulopoiesis was assessed by evaluating key parameters for ANC recovery: the depth of nadir, duration of neutropenia (ANC < 500 cells μL −1 ) and recovery time to ANC ≥ 1, 000 cells μL −1 . Following 10.0 Gy PBI/BM5, the mean duration of neutropenia was 11.6 d in the control cohort vs. 3.5 d and 4.6 d in the day 1 and day 3 Neupogen® cohorts, respectively. The respective ANC nadirs were 94 cells μL −1, 220 cells μL −1, and 243 cells μL −1 for the control and day 1 and day 3 Neupogen® cohorts. Following 11.0 Gy PBI/BM5, the duration of neutropenia was 10.9 d in the control cohort vs. 2.8 d, 3.8 d, and 4.5 d in the day 1, day 3, and day 5 Neupogen® cohorts, respectively. The respective ANC nadirs for the control and day 1, day 3, and day 5 Neupogen® cohorts were 131 cells μL −1, 292 cells μL −1, 236 cells μL −1, and 217 cells μL −1, respectively. Therefore, the acceleration of granulopoiesis by Neupogen® in this model is independent of the time interval between radiation exposure and treatment initiation up to 5 d post-exposure. The PBI/BM5 model can be used to assess medical countermeasure efficacy in the context of the concurrent GI- and H-ARS.