Amorphous solid dispersions and pharmaceutical compositions of the protein kinase inhibitor dasatinib. The pharmaceutical compositions may be used in methods of treating a proliferative disorder such as cancer, or in methods of delivering dasatinib to patients without regard to whether the patient is concurrently administered a gastric acid-reducing agent, or without regard to whether the patient has an elevated gastric pH. The compositions may be particularly suitable for patients afflicted by achlorhydria or hypochlorhydria, or Helicobacter pylori infection.