Lundbeck has hit the acquisition trail to buy Chelsea Therapeutics, getting access to the US company's neurology treatment Northera.

The Danish drugmaker is paying $530 million upfront, or $6.44 per share in cash, a 29% premium on Chelsea's closing price on May 7. The deal also includes a contingent value rights (CVR) element where Lundbeck could pay up to $1.50 per share more, valuing the whole transaction at $658 billion.

The CVR payment will depend on the performance of Northera (droxidopa) which was recently approved by the US Food and Drug Administration and is expected to be launched in the second half of the year. The therapy helps prevent a sometimes debilitating drop in blood pressure and fainting episodes in patients with neurogenic orthostatic hypotension, a chronic disorder caused by an underlying neurogenic disorder, such as Parkinson's disease, multiple system atrophy or pure autonomic failure.  

Ulf Wiinberg, Lundbeck chief executive, said that "as a company committed to people living with brain disorders, we are uniquely positioned to make Northera available to those who need it most".

Earlier this week, Lundbeck posted a 7% decline in first-quarter sales to 3.59 billion kroner (about $665 million), while core earnings before interest and taxes fell 21% to 729 million kroner. However, the company stressed that sales of its existing neurology franchise in the USA - notably Xenazine (tetrabenazine) for chorea associated with Huntington's disease, the epilepsy drug Sabril (vigabatrin) and Onfi (clobazam) for Lennox Gastaut-syndrome - increased by 40% to 744 million kroner.