Disclosed herein are certain crystalline forms of Compound 5, N-(5-((2-(4-(2-oxa-7-azaspiro[3.5]nonan-7-yl)butanamido)imidazo[1,2-0]pyridazin-6-yl)oxy)-2-methylphenyl)-1,3-dimethyl-1/-/-pyrazole-5-carboxamide, as well as pharmaceutical compositions comprising the crystalline forms. The present disclosure further relates to methods for treating or preventing diseases or disorders using the crystalline forms or pharmaceutical compositions thereof in a subject in need thereof, including diseases or disorders associated with abnormal or pathological angiogenesis and/or aberrant signaling of a growth factor signaling pathway (e.g., vascular endothelial growth factor (VEGF)), such as proliferative diseases and ocular diseases.