Today, H. Lundbeck A/S and Merck & Co., Inc. announced results of two phase-II clinical trials with gaboxadol at the 159th Annual Meeting of the American Psychiatric Association (APA). Gaboxadol is an investigational agent in phase III for the treatment of insomnia and the first Selective Extrasynaptic GABAA Agonist (SEGA) constituting a new class of sleep agents.

In the primary insomnia polysomongraph (PSG) study short-term treatment with gaboxadol improved sleep maintenance, enhanced slow wave sleep and was generally well tolerated with no next-day residual effects.

In the transient insomnia study gaboxadol 10 and 15 mg effectively improved traditional PSG and self-reported sleep maintenance and induction measures. Slow wave or deep sleep is associated with delta and theta activity. Gaboxadol 10 and 15 mg increased slow-wave (delta) and theta activity in non-REM sleep in a dose dependent manner. Gaboxadol was well tolerated with a few dose-related, generally mild adverse events. Treatment with gaboxadol did not result in next-day residual effects.

"The phase-II data presented demonstrates a clear differentiation of gaboxadol by enhancing the slow wave activity. We believe that enhanced slow wave sleep will open another field of research to add benefit for patients' condition and performance", says Anders Gersel Pedersen, Head of Development at Lundbeck and continues; "Gaboxadol is in clinical phase-III, which comprises approximately 5,000 patients and together with our partner Merck we expect to file gaboxadol for approval in the US in the beginning of 2007."

Primary insomnia study Design Randomised, double-blind, 4-way crossover, PSG study comparing gaboxadol 10 and 20 mg to placebo in 40 adult patients with primary insomnia. Zolpidem 10 mg was used as an active reference. Treatment was administered on two consecutive nights in each treatment session. Next-day residual effects were evaluated 2 hours after lights on.

Results Gaboxadol 20 mg and zolpidem 10 mg significantly increased total sleep time (TST) with 53 minutes compared to baseline (p<0.05 compared to placebo) and gaboxadol 20 mg significantly reduced wakefulness after sleep onset (WASO) with 27 minutes compared to baseline (p<0.05 compared to placebo). Both gaboxadol 10 and 20 mg but not zolpidem significantly reduced number of awakenings by 9 compared to baseline (p>0.001 compared to placebo). Neither drug significantly reduced sleep onset latency. However, gaboxadol 20 mg improved self-reported "quality of sleep" (p<0.05).

Both gaboxadol doses enhanced slow wave sleep in a dose dependent manner.

Tolerability and next-day residual effects Neither drug treatment was associated with next day residual effects the morning after treatment. The majority of adverse events (AE) were mild or moderate with no serious AEs. Compared to placebo, the incidence and severity of AEs were higher with gaboxadol 20 mg.

Transient insomnia study Design 109 healthy subjects (18-59 years old) completed a randomized, double-blind, 5-way crossover study in a 4 hour phase advance model of transient insomnia. Sleep was assessed using PSG and self-reported measures following gaboxadol 5, 10 and 15 mg versus placebo. Zolpidem 10 mg was used as an active reference.

Results WASO and TST were significantly improved in all active treatments compared to placebo, (WASO p<0.05; TST p<0.001).

Latency to persistent sleep (LPS) was significant shorter than placebo for gaboxadol 10 and 15 mg, (LPS p< 0.05).

Gaboxadol 10 and 15 mg significantly increased slow wave activity (SWA p<0.05) in a dose dependent manner. In contrast zolpidem did not enhance SWA.

Self-reported measures of sleep maintenance showed improvements in both sWASO (p<0.05) and sTST (p<0.05) for all active treatments compared with placebo.

Tolerability and next-day residual effects Gaboxadol was well tolerated with a favourable safety profile. There were no serious adverse events, and no adverse events that led to withdrawal from the study. Majority of adverse events were mild or moderate.

At 30 minutes and 3 hours after lights on, relative to placebo, gaboxadol showed no consistent impairment of measures on various next-day testing parameters.

About gaboxadol Gaboxadol is a novel compound currently in phase III development for the treatment of insomnia. Gaboxadol appears to interact directly with the extrasynaptic GABA receptor recognition site and mediates its effects via a GABAA receptor population that is different from that modulated by benzodiazepine receptor agonists.

About insomnia Insomnia is defined by complaints of inadequate or poor-quality sleep, generally including difficulty falling asleep, waking up frequently during the night with difficulty returning to sleep, and/or experiencing unrestorative sleep. It is estimated that sleep disorders affect approximately one out of four Americans at some time in their lives. (National Institute of Neurological Disorders and Stroke)

The content of this release will have no influence on the Lundbeck Group's financial result for 2006.

Lundbeck contacts

Steen Juul Jensen Vice President +45 36 43 30 06

Media Caroline Broge Investor Jacob Tolstrup contact Media Relations Manager contact Investor Relations Manager +45 36 43 26 38 +45 36 43 30 79