In an international trial spanning 11 countries, the injection was offered to patients whose cancer had spread or come back and whose disease had failed to respond to other treatments.

The jab, called amivantamab, shrank the tumours of more than a third of patients, with dramatic changes seen within weeks. In 15 of them, doctors found the drug had melted away their tumours altogether.

Kevin Harrington, professor in biological cancer therapies at the Institute of Cancer Research, London (ICR), said: These are unprecedentedly strong responses in patients whose disease has become resistant to both chemotherapy and immunotherapy.