The London-based soccer club that shares its name may not have had much of a season, but Chelsea Therapeutics International Ltd. got a result Thursday when H. Lundbeck A/S lined up an agreed bid worth $530 million initially. Milestones attached to the commercial performance of Northera (droxidopa), its recently approved drug for neurogenic orthostatic hypotension (NOH), could push the total value of the deal up to $658 million.

Lundbeck, of Valby, Denmark, is paying $6.44 per share in cash, plus contingent value rights (CVRs) worth up to $1.50 based on sales of Northera from 2015 through 2017. The drug, which the FDA approved Feb. 18, is due to launch in the second half of this year.

So far, at least, the market failed to price in a whole lot of optimism about its prospects, though news of the deal sent shares of Charlotte, N.C.-based Chelsea (NASDAQ:CHTP) surging 31.6 percent Thursday, closing at $6.58, up $1.58, a level that values the CVRs at about 12 cents. Neither company has revealed the sales targets attached to the CVRs.

Investor reaction in Denmark was muted. Shares in Lundbeck (COPENHAGEN:LUN) briefly gained 2 percent immediately after the news was disclosed early afternoon local time to reach a peak of DKK154.10 (US$28.62). The stock closed at DKK153.50, up 1.6 percent.

The up-front portion of the deal represents a 29 percent premium on Chelsea's closing share price of $5 on Wednesday. Should the CVRs pay out in full, the premium would increase to a more generous 59 percent.

NOH, an orphan indication most closely associated with neurological conditions such as Parkinson's disease and multiple system atrophy, refers to the sensation of dizziness and light-headedness a patient experiences on standing up. It can severely impact quality of life and increases the risk of falls and injury. It is caused by a failure of the autonomic nervous system to secrete enough norepinephrine, resulting in insufficient blood pressure.

Northera, which comprises an oral prodrug of norepinephrine, gained an accelerated approval on Feb. 18, at the second time of asking. Chelsea had received a complete response letter in March 2012, despite a 7-4 advisory committee vote in its favor. It is required to conduct a large-scale postmarketing study, which will gobble up most of the dowry – it reported $45.3 million in cash at the end of 2013 – it brought to the deal.

Northera faces competition from a generic vasoconstrictor, Proamatine (midodrine), marketed by Dublin-based Shire plc, and a corticosteroid called Florinef (fludrocortisone), which is used off-label to treat NOH. Even so, one analyst has forecast worldwide sales of $550 million, with $460 million of that coming from the U.S. (See BioWorld Today, Feb. 20, 2014.)

Lundbeck's ambitions are a little more modest. "If we succeed as we hope, our peak sales expectations would be about the DKK1.5 billion mark," company spokesman Mads Kronborg told BioWorld Today. That's about $280 million, although the figure refers to the U.S. only. "If we succeed in acquiring Chelsea then we will have more or less global rights," he said. "We will be focusing on the U.S. first and foremost."

The company is building a neurology portfolio in the U.S. market, as part of its efforts to combat revenue losses associated with generic erosion in that territory of mature products, notably depression drug Cipralex (escitalopram). Northera likely will be the biggest seller in that portfolio.

It's an open question for now whether Lundbeck will seek registration in Europe. In Asia, rights to Japan, China, South Korea and Taiwan are held by Osaka, Japan-based Dainippon Sumitomo Pharma Co. Ltd., which licensed the drug in other territories to Chelsea back in 2006. Dainippon also retains an economic interest in sales of the drug elsewhere. "There will be a small royalty. It will be a single-digit thing," Kronborg said.