The news comes after New York’s Attorney General Eric Schneiderman brought a lawsuit against the company on 15 September 2014 accusing them of carrying out the illegal practice of ‘forced switching’ in order to avoid competition from generics.

Under such a manoeuvre, a pharmaceutical company that sells a medicine facing imminent generics competition withdraws its drug from the market, forcing patients to switch to a different form and impeding the entry of low cost generics, according to the complaint.

In this case, Actavis planned to discontinue the immediate-release version of its Alzheimer’s drug Namenda IR (memantine) and switch patients to an extended-release version Namenda ER. The patent on Namenda IR, which generated US$1.5 billion in sales in 2013, is due to expire in January 2015. The patent on the newer version expires in 2025.

Actavis subsidiary Forest Laboratories announced in February 2014 that it would discontinue the sale of Namenda IR from 15 August 2014, according to the lawsuit. In mid-September 2014, it said it planned to stop sale of the tablets in the autumn of 2014. This vagueness about the timing of discontinuation has also been accused of encouraging physicians to move more quickly to consider switching patients to a new version, rather than waiting for a generic version. 

According to the complaint, to date, more than 40% of existing patients have switched from Namenda IR to Namenda XR in anticipation of the discontinuance. This means that these patients will be less likely to switch to a generic version of the immediate-release version once patents expire in January 2015.

Forest Laboratories has also filed a lawsuit against generics makers Sun Pharma Global, Teva Pharmaceuticals USA and Wockhardt Bio, all of whom have filed abbreviated new drug applications (ANDAs) with the US Food and Drug Administration (FDA) seeking approval to market generics of Namenda XR [1].

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Reference
1.   GaBI Online - Generics and Biosimilars Initiative. Forest Labs files lawsuit to stop generic memantine [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2014 Oct 10]. Available from: www.gabionline.net/Generics/News/Forest-Labs-files-lawsuit-to-stop-generic-memantine

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