The present invention concerns methods comprising co-administration of pegfilgrastim and romiplostim for treatment of diseases and conditions characterized by low neutrophil levels (neutropenia) and/or low platelet levels (thrombocytopenia). The present invention concerns an enhanced effect on neutrophil levels and on platelet levels resulting from co-administration of pegfilgrastim and romiplostim. The present invention further concerns a method of treating a patient who has been exposed to radiation, which comprises administering romiplostim at a dose of about 1 to about 10 g/kg. The invention further concerns such methods wherein a single dose of romiplostim is administered to the patient and wherein romiplostim is administered about 24 hours or less after the radiation exposure. The invention further concerns treatment with romiplostim and pegfilgrastim for radiation exposure. Such methods relate to treatment of acute radiation syndrome and treatment to counteract the effects of radiation therapy and other sources of radiation exposure.

The present invention concerns methods comprising co-administration of pegfilgrastim and romiplostim for treatment of diseases and conditions characterized by low neutrophil levels (neutropenia) and/or low platelet levels (thrombocytopenia). The present invention concerns an enhanced effect on neutrophil levels and on platelet levels resulting from co-administration of pegfilgrastim and romiplostim. The present invention further concerns a method of treating a patient who has been exposed to radiation, which comprises administering romiplostim at a dose of about 1 to about 10 g/kg. The invention further concerns such methods wherein a single dose of romiplostim is administered to the patient and wherein romiplostim is administered about 24 hours or less after the radiation exposure. The invention further concerns treatment with romiplostim and pegfilgrastim for radiation exposure. Such methods relate to treatment of acute radiation syndrome and treatment to counteract the effects of radiation therapy and other sources of radiation exposure.

The present invention concerns a method of treating idiopathic thrombocytopenia purpura (ITP) in a patient having ITP, which comprises: (a) administering romiplostim weekly to the patient; (b) increasing the weekly dose until a platelet count of at least about 50 to 20010.sup.9/L is reached; (c) decreasing the weekly dose of romiplostim if the platelet count remains 20010.sup.9/L for two consecutive weeks; (d) discontinuing romiplostim if the platelet count has remained 20010.sup.9/L for two consecutive weeks when the weekly dose is 1 g/kg or the platelet count is 40010.sup.9/L; and (e) if a platelet count 20010.sup.9/L is reached within the first 4 to 12 weeks of treatment, maintaining a treatment-free period of at least about 24 weeks during which the patient receives no romiplostim.

Methods and kits for mitigating a toxic effect of at least one of vesicants and caustic gases in a subject in need thereof are described. In particular, an effective amount of a thrombopoietin (TPO) mimetic, such as RWJ-800088 or romiplostim, is used to mitigate the toxic effect of the vesicant or caustic gas.

Methods and kits for mitigating liver injury and promoting liver regeneration and engraftment in a subject treated with a targeted radiation therapy are described. In particular, an effective amount of a thrombopoietin mimetic, such as RWJ-800088 or romiplostim, is used to mitigate the radiation-induced liver diseases and promote beneficial effects for liver regeneration and engraftment in conjunction with radiation or radiomimetics.

Methods and kits for mitigating liver injury and promoting liver regeneration and engraftment in a subject treated with a targeted radiation therapy are described. In particular, an effective amount of a thrombopoietin mimetic, such as RWJ-800088 or romiplostim, is used to mitigate the radiation-induced liver diseases and promote beneficial effects for liver regeneration and engraftment in conjunction with radiation or radiomimetics.

Methods of mitigating vascular injury, promoting organ and hematopoietic recovery, accelerating vascular recovery, and enhancing survival in a subject treated with radiation therapy or chemotherapy are described. In particular, an effective amount of a thrombopoietin (TPO) mimetic, such as RWJ-800088, is used at the appropriate times relative to the Total Body Irradiation or Chemotherapy exposure to achieve these prophylactic and/or therapeutic benefits.

A method for treating a defect site in a living bone of an animal by applying an exogenous compound having thrombopoietic activity to the defect site in an amount effective to induce thrombopoiesis. The exogenous compound activates a thrombopoietin receptor, leading to accelerated bone formation at the defect site. Also provided is a method for repairing a segmental bone defect in an animal bone by inserting into the segmental bone defect a biodegradable bone repair scaffold that contains a compound having thrombopoietic activity. The compound activates a thrombopoietin receptor and accelerates bone formation such that bridging occurs at the segmental bone defect.

Methods of protecting vascular integrity in a subject exposed to a targeted radiation therapy are described. In particular, an effective amount of a thrombopoietin (TPO) mimetic, such as TPOm, is used to protect vascular integrity following the radiation therapy.

Modified natural killer (NK) or T cells expressing hematopoietic growth factor receptors are provided. In some aspects, the modified NK cells or T cells express a thrombopoietin receptor, an erythropoietin receptor, or a chimeric polypeptide including an extracellular domain of a thrombopoietin receptor, a transmembrane domain, and an intracellular domain including an interleukin-2 receptor beta intracellular signaling domain. Methods of treating a subject with cancer are also provided, including administering the modified NK cells or T cells to the subject in combination with a thrombopoietin receptor agonist or erythropoietin receptor agonist, and in some example, interleukin-2, particularly reduced or low-dose amounts of IL-2.