That’s the implication from the latest news to dribble out of Wall Street. An analyst indicated that Merck’s experimental taranabant obesity pill didn’t yield the hoped-for weight loss of 5 percent at the 2 mg dose the drugmaker hopes to sell, according to Reuters. And this occurred in Phase III testing, according to Aileen Salares of Leerink Swann, which isn’t a good sign.

The 4 mg dose achieved the desired weight loss but came with a significant catch - the dosage more than doubled instances of psychiatric side effects than a placebo. And even the 2 mg dose proved problematic: nearly twice as many patients taking it removed themselves from the trial, compared with the placebo, citing suicidal thoughts and neurological effects, according to Salares. “Safety was not nearly as clean as expected, though,” she tells Reuters.

Salares based her analysis on an abstract of the two-year study. Full data will be formally presented late this month at the annual meeting of the American College of Cardiology in Chicago at month’s end.

Mid-stage trials reported recently displayed the same findings. Could this be a problem for Merck? You may recall that the Merck pill is similar to Acomplia, the Sanofi-Aventis fat fighter that failed to win FDA approval over psychiatric side effects, specifically depression and suicide. Both drugs work by blocking cannabinoid receptors in the brain, which give people the munchies when they smoke marijuana.