The first phase III data on Otsuka and Lundbeck’s new antidepressant brexpiprazole is positive and will be presented at a conference in March, said the companies last week.
Brexpiprazole (OPC-34712) is a dopamine D2 and serotonin 5-HT1A partial agonist in development as a successor to the two companies’ atypical antipsychotic Abilify (aripiprazole) – the top-selling drug in the US in the third quarter of 2013.
Abilify has already lost patent protection in a number of markets, however, and loses exclusivity in the US in April 2015 when the market will open up to generic competition.
While aripiprazole’s primary use is in schizophrenia and bipolar disorder, it has increasingly been used as an add-on treatment for adults with major depressive disorder (MDD) who continue to have unresolved symptoms after at least six weeks on antidepressant therapy.
Like its parent, brexpiprazole is also positioned initially as an add-on therapy in depression but with an improved tolerability profile, and Otsuka and Lundbeck have said they saw a number of benefits over antidepressant therapy alone in the phase III study.
Adding brexpiprazole to existing antidepressant therapy achieved a significant improvement in the Montgomery-Åsberg Depression Rating Scale (MADRS) compared to placebo – the primary endpoint in the trial – as well as a series of secondary efficacy endpoints.
Lundbeck noted that three additional studies of brexpiprazole in depression and schizophrenia are due to report results in the first half of 2014 and – if positive – could support a brexpiprazole filing in the US before the end of the year.
Approval would reinforce Lundbeck and Otsuka’s central nervous system franchise, which was also boosted last year by the approval of a once-monthly formulation of aripiprazole – Abilify Maintena – which is expected to be a big growth driver for both companies in the coming years.
Lundbeck and Otsuka renewed their CNS alliance on the back of US approval of Abilify Maintena last March, extending it to include a candidate for Alzheimer’s disease called Lu AE58054 a couple of weeks later.
Analysts have suggested Abilify Maintena could achieves sales of $800m-plus in 2018 with some suggesting brexpiprazole could reach more than $2bn at peak, provided its profile shows an advantage over aripiprazole. Others suggest its profile would have to be very much improved indeed to offset the much lower cost of generic aripiprazole.
Lundbeck will share 50 per cent of net sales in Europe and Canada, and 45 per cent of net sales in the US.