As schizophrenia rivals rush in, Otsuka and Lundbeck gain FDA OK for Rexulti

Otsuka and its partner Lundbeck snagged an FDA approval for Rexulti (brexpiprazole) to treat schizophrenia and as an add-on therapy for major depression, leaving the two companies prepping for an August launch into an increasingly crowded field.

The approval marks a major turning point for the two companies' 4-year-old partnership, in which Lundbeck promised up to $1.6 billion and chipped in collaborations on three early-stage programs in exchange for commercial rights to Rexulti and an extended-release version of Abilify (aripiprazole).

Both companies saw the development pact as a way to contend with the loss of patent protection on key franchise drugs. Abilify Maintena was approved in 2013 and Otsuka and Bristol-Myers Squibb ($BMY) lost a rearguard action against generics of the original Abilify earlier this year, exposing both companies to the loss of blockbuster revenue. Teva ($TEVA) was one of the first challengers to move in on that market, with more on the near horizon.

Now Otsuka and Lundbeck will try to position Rexulti as a better, branded alternative to generic Abilify. The development program included studies with more than 4,000 patients, and the partners can point to a somewhat improved side effect profile compared to Abilify, while there was also evidence of additional weight gain that won't help.

Alkermes ($ALKS) has been developing its own version of a long-acting aripiprazole. The FDA accepted that application for review last fall. Another antipsychotic, ALKS 3831, is in development to treat schizophrenia without the weight gain associated with rival therapies.

Investigators are also clear that they're not exactly sure how this drug works, noting that it triggers partial agonist activity at serotonin 5-HT1A and dopamine D2 receptors, and antagonist activity at serotonin 5-HT2A receptors.

"All treatment options require healthcare providers, patients and caregivers to balance efficacy and tolerability in managing their diseases," said Lundbeck CEO Kåre Schultz. "We are proud to introduce Rexulti to help adult patients living with MDD and schizophrenia."

- here's the release