Total: $160.7 million

Pfizer's ($PFE) rheumatoid arthritis drug Xeljanz has been gaining steam since its launch in 2012, both in ad spending and in sales. Pfizer spent more than $160 million last year to advertise Xeljanz, up 69% from $94.9 million in 2013. Sales leaps were even higher, with Pfizer recording a revenue increase of 170% year over year to $308 million for the drug. Still, Xeljanz has been another slow-to-grow drug for Pfizer, which had once pegged peak sales expectations at $3 billion annually.

Xeljanz was accepted earlier this year for FDA review for the treatment of adult psoriasis, an indication that could boost sales, although it's entering an already crowded field where blockbuster Humira is well entrenched.

For more:
Psoriasis data wars heat up at AAD with Novartis, Boehringer studies
Psoriasis study does little to help Pfizer with Xeljanz
Pfizer's potential stars Eliquis, Xeljanz see sluggish sales