By Aiswariya Chidambaram, Healthcare

Atypical antipsychotics are the most expensive drugs prescribed for bipolar disorder, contributing nearly three-fourth of the revenues of the European bipolar disorder therapeutics market, which was valued at $1.20 billion in 2011. It is interesting to note that nearly 18 per cent of the total atypical antipsychotic drugs in Europe are prescribed for bipolar disorders. The average annual expenditure for bipolar disorder in Europe was estimated to be $48,954.69 million in 2011, making it one of the greatest economic burdens to the European Government. However, the direct healthcare costs (drugs) of bipolar disorder are likely to reduce significantly in the next few years until 2013 due to the patent expiry of several key blockbuster atypical antipsychotics and availability of cheaper generic versions in Europe. While this would translate into huge cost savings for the patients, insurance payers and the Government, the innovator pharmaceutical companies are likely to experience a whopping 30 to 50 per cent slash in their revenues, thereby causing a decline in growth of the European bipolar disorder therapeutics market.

Generics Lead the Way Ahead

Historically, the European bipolar disorder therapeutics market witnessed moderate-to-high growth rates from 2000 to 2007 dueto the approval of several potential atypical antipsychotics during this period.

The first key blockbuster atypical antipsychotic that lost patent protection was Risperdal®(risperidone) from Johnson & Johnson in 2008, following which was Zyprexa (olanzapine) from Eli Lilly, which recently had its patent expire in April 2011. Moving ahead, four blockbuster atypical antipsychotics are due to lose their patent protection, which include Seroquel® IR (quetiapine fumarate) from AstraZeneca and Geodon (ziprasidone) from Pfizer Inc. in 2012, Abilify® (aripiprazole) from Bristol-Myers Squibb in 2014 and Saphris® (asenapine) from Merck in 2015. This is expected to cause an overall decrease of 10.1 per cent in the European bipolar disorder therapeutics market until 2013. As generic equivalents of these blockbuster drugs reach the market, prices are expected to fall between 30 to 60 per cent over the next five years (2011 - 2015).

Improving New Drug Formulations

With more than 80 per cent of the key atypical antipsychotics facing competition from cheaper generic versions, the innovator companies have been pro-active to sustain their market positions by developing improved new drug formulations, particularly the depot (injectable) formulations of atypical antipsychotics, which improves not only the efficacy and safety but also the overall performance of the drug. The best example of this is the injectable, long-acting form of risperidone, namely Risperdal® Consta®, which generated worldwide sales revenue of $1.5 billion in 2010. Depot formulation of Abilify, Abilify Paliperidoneis expected to be launched by 2013.  Certain companies such as Alexza pharmaceuticals have also developed novel, non-invasive technologies like the Staccato® system which ensures rapid onset of action, patient compliance and reduced side effects for the treatment of agitation in bipolar disorder patients. Eli Lilly's LY2140023, expected to be launched in 2014 in Europe, is likely to be one of its kind, with a novel mechanism of action as opposed to the traditional atypical antipsychotics. These emerging new drug formulations are expected to command premium pricing strategies and restore moderate growth rates in the European bipolar disorder therapeutics market between 2014 and 2018.

Increasing Investments in R&D: What's in the Pipeline?

Currently,more than3 million people are diagnosed with bipolar disorder (any one of the bipolar disorders) in Europe, and this number is estimated to double by 2018. The bipolar nature of the disease makes accurate diagnosis a key challenge, which leaves a large part of the population undiagnosed and untreated. Moreover, nearly 15.1 per cent of the diagnosed bipolar disorder patients do not resort to any form of treatment in Europe. Although atypical antipsychotics and mood stabilising drugs are the most predominantly used medication for bipolar disorder in Europe, they present promising results only for the treatment of acute mania or hypomania. Treatment of bipolar depression still remains a major challenge, with only one approved atypical antipsychotic, Seroquel® (AstraZeneca) in the European market till date. Given the large amount of unmet clinical needs, huge patient potential and immense market opportunities, the big pharma and specialty pharmaceutical companies are increasingly focusing on mental disorders, particularly schizophrenia, depression and bipolar disorder. Companies such as Gedeon Richter and Lundbeck have invested more than13 per cent and 20 per cent,respectively,of their annual turnover in R&D of CNS disorders and have several ongoing projects in the pipeline.

Despite the fact that bipolar disorder is one among the least researched diseases, currently, there are four potential phase III drug candidates in the pipeline, of which two are atypical antipsychotics. RGH188 (cariprazine) from Gedeon Richter showed statistically significant results in the phase III trials for acute mania; currently, phase II clinical trials are on-going for efficacy of cariprazine in bipolar depression. Another potential phase III drug candidate in the pipeline includes Latuda® (lurasidone hydrochloride) from Dainippon Sumitomo Pharma indicated for bipolar depression, bipolar maintenance and schizophrenia, which is expected to gain approval by 2013. It is important to note that drugs thattarget bipolar depression are the need of the hour and can make a significant impact on the bipolar disorder therapeutics market.

Conclusion

The European bipolar disorder therapeutics market is anticipated to witness a decline till 2013 dueto the patent expiry of key blockbuster atypical antipsychotics. However, approval of new drugs and improved depot formulations are expected to drive moderate growth from 2014 to 2018.