By Rupert Hargreaves Pharmaceutical group GSK has been granted breakthrough therapy designation by the US Food and Drug Administration (FDA) for a key lung cancer treatment. The breakthrough therapy designation is designed to expedite the development and review of drugs with the potential to treat a serious condition. Only treatments that are shown to offer a substantial improvement over currently available therapy are awarded this designation. GSK’s treatment, its investigational B7-H3-targeted antibody drug conjugate, or GSK’227, is being evaluated for the treatment of patients with extensiv…