Neratinib (Nerlynx™) is an oral, irreversible inhibitor of the human epidermal growth factor receptors HER1 (EGFR), HER2 and HER4. The drug originally arose from research by Wyeth (now Pfizer) and is now being developed by Puma Biotechnology primarily for the treatment of HER2-positive (HER+) breast cancer. Neratinib is approved in the USA for the extended adjuvant treatment of patients with HER2+ early-stage breast cancer who have been previously treated with a trastuzumab-based adjuvant regimen, and is in the preregistration phase for this indication in the EU. Neratinib, as monotherapy and/or combination therapy, is also in phase 3 development for metastatic breast cancer and in phase 1/2 development for advanced breast cancer and other solid tumours, including non-small cell lung cancer, colorectal cancer and glioblastoma. This article summarizes the milestones in the development of neratinib leading to this first approval for breast cancer.