Some lung cancers, caused by smoking, have been found to contain a receptor family called FGFR which drive growth of the tumour and can cause resistance to chemotherapy. New drugs designed to block FGFR display severe side effects, such as tissue calcification and anorexia. These toxicities result from blocking the important functions of FGFR in healthy tissues and may prevent giving a large enough dose to patients to treat their lung cancer. We have invented a 'stealth' drug technology that can substantially increase the delivery of active drug to the tumour, whilst sparing the normal tissues. The first example, PR610, designed to drug a related receptor family, entered human clinical trials in New Zealand and the USA in 2012. We will now use this technology and standard medicinal chemistry methodologies to make new FGFR drugs that promise to be less toxic and more effective for treating smoking-related lung cancer.