Swiss drugmaker Novartis on Monday said it is jettisoning what it had hoped would be a billion-dollar-selling asthma drug, fevipiprant, from its development program after the medicine failed another set of key trials.

The drug’s star fell in October when the Basel-based company announced it had failed a pair of trials in moderate asthmatic patients.

Now, fevipiprant has flopped in two additional studies in moderate-to-severe patients, spelling the end to its development for asthma.

Novartis chief drug developer John Tsai had continued to hold out hope that the trial failures in moderate patients were a fluke and that the drug would be more effective in patients hit harder by the respiratory disorder.