Sargramostim

Sargramostim is a recombinant form of GM-CSF, a cytokine that acts on hematopoietic progenitor cells to stimulate the proliferation, differentiation, and functional activation of granulocytes (neutrophils, eosinophils) and macrophages. Unlike filgrastim (G-CSF), which is more lineage-specific for neutrophils, GM-CSF has a broader effect on multiple myeloid lineages, including monocytes/macrophages and dendritic cells, giving it additional immunomodulatory properties. Clinically, it is used to: (1) accelerate myeloid recovery following autologous or allogeneic bone marrow transplantation, (2) treat chemotherapy-induced neutropenia to reduce infection risk and shorten the duration of neutropenia, (3) mobilize peripheral blood hematopoietic stem cells before collection for transplantation, and (4) manage neutropenia following induction chemotherapy for acute myeloid leukemia in older adults. It has also been studied as an adjuvant in cancer immunotherapy (e.g., with sipuleucel-T for prostate cancer) due to its ability to enhance antigen presentation via dendritic cells. Adverse effects include bone pain, fever, malaise, fluid retention (capillary leak syndrome), and rarely supraventricular arrhythmias. It is contraindicated in patients with excessive leukemic myeloid blasts (>10%) due to risk of stimulating blast proliferation. Mechanistically, it binds to GM-CSF receptors on myeloid progenitor cells, activating the JAK2-STAT5 signaling pathway to promote cell survival, proliferation, and differentiation. Boards often test the distinction between G-CSF (filgrastim, pegfilgrastim) and GM-CSF (sargramostim) in terms of mechanism, indications, and side effect profiles.