Namenda

Analyst Outlook

Namenda’s (memantine; Allergan/Lundbeck/Daiichi Sankyo) global sales have peaked at approximately

$2.3bn in 2014, making it the current leader in the Alzheimer’s disease market. Namenda has grown

as a successful brand as a result of its novel mode of action and positioning as an add-on therapy for

patients with moderate to severe Alzheimer’s disease. However, with the onset of generic erosion and

successful reformulations of competitor products targeting the severe Alzheimer’s disease market,

Namenda will be unable to continue its sales growth. Allergan’s lifecycle management strategy – the

launches of Namenda XR and Namzaric – will likely lessen sales erosion in the US, but will be unable

to prevent the inevitable decline in sales that accompanies patent expiries.

Drug Overview

Namenda is a first in-class, N-methyl-D-aspartate (NMDA) receptor antagonist indicated for the

treatment of moderate to severe Alzheimer’s disease. It is a voltage-dependent uncompetitive

antagonist, with low to moderate affinity to the NMDA receptor. By blocking the activity of the

NMDA receptor, it decreases glutamate-induced prolonged calcium influx, thereby limiting the

occurrence of neurotoxicity and cell death, which are underlying pathologies in Alzheimer’s disease

(Actavis, 2003; FDA, 2014a; Parsons et al., 2013). This alternative mode of action has enabled the drug

to find use as an adjunctive to cholinesterase inhibitors.

Memantine was first launched by Merz in Germany in 1982, although it was not until December 2002

that it was more widely commercialized in the EU by Lundbeck, under the brand name Ebixa (EMA,

2015). Forest Laboratories, now part of Allergan, subsequently launched the drug in the US in January

2004 under the brand name Namenda (Pharmaprojects, 2015; Allergan, 2014). In both regions,

Namenda is approved for moderate to severe Alzheimer’s disease. Furthermore, Merz’s commercial

partner for memantine in Japan, Daiichi Sankyo, launched the product for moderate to severe

Alzheimer’s disease under the brand name Memary in June 2011 (Daiichi Sankyo, 2011). Lundbeck and

Allergan also filed for an extension of Namenda’s label to include patients with mild to moderate

Alzheimer’s disease, although the company’s applications to the European Medicines Agency and the

US Food and Drug Administration (FDA) were ultimately unsuccessful (Biomedtracker, 2015).

Namenda is available in 5mg and 10mg tablets, to be taken twice daily. Given that the US product

patent expired in October 2015, Allergan pre-emptively launched Namenda XR in June 2013, a 28mg

once-daily extended-release tablet. Allergan has also developed a fixed-dose combination (FDC) of

Namenda XR with donepezil, marketed as Namzaric, in collaboration with Adamas Pharmaceuticals.

This co-formulation was approved in the US in December 2014 (Biomedtracker, 2015; Medtrack,

2015).