Shares of British cancer specialist Antisoma plunged after a lung cancer drug it developed with Swiss pharmaceutical giant Novartis failed in a trial.
Antisoma shares dived 66% to 10.9p, valuing the company at about £70m, down from £200m on Friday.
ASA404 had been Antisoma's most valuable experimental product, which is now unlikely to get further funding. The trial, in its final phase III, failed to demonstrate the drug had any sign of improving patients' condition. Broker Peel Hunt cut the company's target price to 33p, from 70p. "The project was a significant fraction of our valuation of Antisoma, so now we believe the drug has 0% chances of success, even though more trials are continuing," said Paul Cuddon, a pharmaceutical analyst at Peel Hunt.
London-based Antisoma focuses on the research and development of drugs. The company also has AS1413, to treat leukaemia, in the final phase of trials. "That's why our valuation isn't totally cut down," Cuddon said.
Novartis, a multi-million pound business that also produces and markets medicines around the world, lost 0.8% to 57 Swiss francs (£35.86) in Zurich.
