The FDA doesn't have to follow the advice of its expert review panels, but it usually does. That's a standard line in stories about advisory committee votes. Unfortunately for Lundbeck and Takeda, their new Brintellix app is one of the unlucky ones.

The agency issued a complete response letter on new labeling that might have given Brintellix a new edge in the crowded antidepressant field. The claim: Brintellix can give a brainpower boost to depressed patients, whose thinking abilities often suffer.

Lundbeck and Takeda had scored study data showing that the novel med can help patients think, pay attention, and make decisions--something no other antidepressant had managed to pull off. And the trial didn't test Brintellix against a placebo, but head-to-head with Eli Lilly's ($LLY) rival drug Cymbalta.

When an FDA advisory panel met last month to review those data, they voted 8-2 for an approval. European regulators had already approved a new use for Brintellix, to improve cognitive function in depressed adults.

The FDA didn't agree, and that puts Lundbeck and Takeda's long-term sales projection--$2 billion--in jeopardy. Lundbeck developed the med, and Takeda has U.S. marketing rights under a marketing deal with the Danish drugmaker.

Naturally, Takeda and Lundbeck said they are disappointed with the FDA's decision, given that the committee decided the companies "presented substantial evidence to support a claim of effectiveness for Brintellix in treating certain aspects of cognitive dysfunction in adults with MDD."

The companies were pleased, however, that the FDA did acknowledge that cognitive dysfunction in major depressive disorder is "a legitimate target for drug development," the companies said in a statement. They said they're looking forward to reviewing the CRL with the FDA "to determine the appropriate path forward."

In any case, the hoped-for cognitive claim will be delayed at best, and with just $94 million in 2015 sales, Brintellix hasn't lived up to early launch expectations. It faces considerable competition in depression, particularly now that a raft of commonly used meds--including Pfizer's ($PFE) Zoloft, Eli Lilly's Prozac and GlaxoSmithKline's ($GSK) Paxil--are now available in cheap generic versions. And with payers requiring patients to try older, less expensive meds before moving to brands, the marketing task for Brintellix has been heavy.

After the panel vote last month, one investment firm pointed out that Brintellix would be "the only product on the market with a leaflet on cognitive effects," Alm. Brand wrote in a note to clients. Focusing label language on improvements in thinking, attention and decision-making "means doctors also will," the firm said.

Meanwhile, Lundbeck has been laying off workers and cutting other costs as part of a plan to save 3 billion kronor, or about $445 million, in annual costs by 2017. Most of the cuts were focused on the company's HQ in Denmark and commercial operations, mainly in Europe.

- see Takeda and Lundbeck's release

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