FRANKFURT, Jan 20 (Reuters) - Germany's Merck KGaA said the most important clinical trial testing its cancer drug hopeful bintrafusp alfa, which it is co-developing with GlaxoSmithKline, would be stopped because the treatment does not appear to work.

In a statement on Wednesday, the drugmaker said the trial dubbed INTR@PID Lung 037, testing the novel drug against Merck & Co's Keytruda in newly diagnosed cases of a certain type of lung cancer, would be discontinued because independent supervisors concluded the drug was unlikely to show the desired efficacy. (Reporting by Ludwig Burger; editing by Thomas Seythal)