Drug In Focus April 2011

INN Constraint Comment

At the time of publication, patents within the original API family are still valid in certain countries and hence are potentially preventing the launch of generics. In several European states, the European patent in this family has had Supplementary Protection Certificates (SPCs) granted with expiries of March 2012, however it should be noted that in certain European countries, the patents claim processes for the preparation of Quetiapine and as such may be circumvented.

In Australia and the US, patent extensions have been granted for the Seroquel IR formulations extending the patent protection until March 2012 (the US patent includes a 6 month paediatric extension); however generics for the IR formulations have been identified in Australia. Whilst no generics have currently been identified in the US, the US patent mentioned above is the subject of litigation regarding several Paragraph IV filings (See Figure 4). The Canadian equivalent of the API family has expired and there has been considerable generic activity for the IR formulations in Canada. The second patent family relates to processes for the production of Quetiapine and as such is not considered to be constraining.

AstraZeneca reported a growth of 66% in global sales for the Seroquel XR formulations in the period 2009-2010, whereas sales of the IR formulations decreased by 1% over the same period. This data is significant and highlights the importance of the extended-release formulations within the marketplace, both for the innovator and any potential generic manufacturers. In terms of these Seroquel XR formulations, the third and fourth patent families are worthy of detailed consideration as they appear to protect the extended-release formulations of Quetiapine.

In the majority of territories these patents are due to expire in May 2017. In the US, equivalent patent protection is extended to November 2017 via a 6 month paediatric extension. This FDA Orange Book listed patent (US 5,948,437) is also the subject of litigation, with Paragraph IV filings and subsequent infringement proceedings having been identified concerning the Seroquel XR formulations between AstraZeneca and several generic companies (See Figure 4).

Figure 2:  Key Patent Indicator; the most significant patents protecting products containing Quetiapine

 

 

Figure 5: Marketing Authorisations for products containing Quetiapine in Key Countries

In the UK, data exclusivity expired in July 2007 and since late 2008 a great number of generic marketing authorisations have been approved, suggesting that generic competition will be fierce upon expiry of the API patent in the UK. The Canadian data highlights the presence of a large number of generics currently available. There is currently no evidence of any marketing authorisations obtained by generic companies relating to the extended-release formulations..

Figure 6: Top Patent Applicants

A representation of patentees who have filed the most patent families for this INN.

Represents the timing of the earliest priority filing date for each patent family identified for this molecule as well as the type of claims found in the applications. Note the consistent patenting by generic companies post-approval (1997 for Seroquel IR in the US) in the area of process, use and formulation, and the relative increase in formulation patent filings following approval of Seroquel XR (2007-2008).