Hematopoietic Recovery using Multi-Cytokine Therapy in 8 Patients Presenting Radiation-Induced Myelosuppression after Radiological Accidents

International audienceTreatment of accidental radiation-induced myelosuppressionis primarily based on supportive care and requiresspecific treatment based on hematopoietic growth factorsinjection or hematopoietic cell transplantation for the mostsevere cases. The cytokines used consisted of pegylatederythropoietin (darbepoetin alfa) 500 IU once per week,pegylated G-CSF (pegfilgrastim) 6 mg 3 2 once, stem cellfactor 20 lg.kg–1 for five days, and romiplostim (TPO analog)10 lg.kg1 once per week, with different combinationsdepending on the accidents. As the stem cell factor did nothave regulatory approval for clinical use in France, theFrench regulatory authorities (ANSM, formerly, AFSSAPS)approved their compassionate use as an investigational drug‘‘on a case-by-case basis’’. According to the evolution andclinical characteristics, each patient’s treatment was adoptedon an individual basis. Daily blood count allows initiating GCSFand SCF delivery when granulocyte ,1,000/mm3, TPOdelivery when platelets ,50,000/mm3, and EPO when Hb,80g/L. The length of each treatment was based on blood cellrecovery criteria. The concept of ‘‘stimulation strategy’’ islinked to each patient’s residual hematopoiesis, which variesamong them, depending on the radiation exposure’s characteristicsand heterogeneity. This paper reports the medicalmanagement of 8 overexposed patients to ionizing radiation.The recovery of bone marrow function after myelosuppressionwas accelerated using growth factors, optimized bymultiple-line combinations. Particularly in the event ofprolonged exposure to ionizing radiation in dose ranges inducing severe myelosuppression (in the order of 5 to 8 Gy),with no indication of hematopoietic stem cell transplantation