Shares of Horizon Pharma Inc. hit a 52-week high Wednesday on news that the specialty pharma firm is acquiring Dublin-based Vidara Therapeutics International Ltd. in a deal valued at about $660 million, adding a fourth marketed product to its pipeline and, more importantly, shifting its headquarters to Ireland to take advantage of that country’s low corporate tax rate.

The move was applauded on Wall Street. Horizon’s shares (NASDAQ:HZNP) closed Wednesday at $16.02, up $1.34, or 9 percent, after reaching $18.30 in early trading, by far the highest the stock has traded since the company went public in 2011. (See BioWorld Today, July 29, 2011.)

Under the terms, Horizon will buy Vidara through a reverse merger transaction involving stock and cash, paying Vidara shareholders about $200 million in cash. Horizon, which ended 2013 with about $80.4 million on its balance sheet, secured a $250 million bridge loan commitment from Deerfield Management Co. LP.

Upon close of the merger, expected around midyear, Horizon shareholders would hold about 74 percent of the new company, Horizon Pharma plc, leaving Vidara shareholders with the remaining 26 percent. The combined firm would be headed by current Horizon chairman, president and CEO, Tim Walbert, with Vidara’s president and chief medical officer, Virinder Nohria, joining the firm’s board.

Vidara has a staff of 24, including a “high single digit” number of sales reps for Actimmune, a bioengineered form of interferon gamma-1b, approved for chronic granulomatous disease (CGD) and severe, malignant osteopetrosis (SMO). Acquired in 2012 from Intermune Inc., which opted to jettison Actimmune after it failed in idiopathic pulmonary fibrosis, Vidara had initiated efforts to improve diagnosis and compliance, explained Walbert, during a conference call Wednesday morning. (See BioWorld Today, May 23, 2012.)

Full-year 2013 sales of Actimmune reached $58.9 million.

Walbert said Horizon plans to maintain the concentrated sales force for Actimmune, while using its own primary care sales force, which markets nonsteroidal anti-inflammatory drugs (NSAIDs) Duexis (ibuprofen/famotidine) and recent acquisition Vimovo (naproxen/esomoeprazole magnesium) – Horizon licensed U.S. commercial rights from Pozen Inc. late last year – to enhance education efforts for Actimmune, particularly in CGD, a phagocyte failure-induced primary immune deficiency disease that remains “significantly underdiagnosed,” Walbert said. (See BioWorld Today, Nov. 20, 2013.)

With the addition of Actimmune to the portfolio, Horizon estimates full-year 2014 revenue of $250 million to $265 million.

The deal “will accelerate our transformation into a profitable specialty pharma company,” Walbert said.

LUCK OF THE IRISH

Also expected to help that transformation is Horizon’s move to Ireland, a strategy that has worked well for other U.S. firms, helping them to expand their international footprint while taking advantage of Ireland’s attractive 12.5 percent corporate tax rate.

Like Horizon, most have made the transatlantic relocation via acquisition. In 2011, Alkermes plc started its new life as an Irish company, following completion of its cash and stock buyout of Elan Drug Technologies, the drug delivery organization of Elan Corp. plc. Since launching its new operations in Dublin in late 2011, Alkermes’ shares have gained more than 180 percent. (See BioWorld Today, May 10, 2011.)

Two years later, Dublin-based Elan, itself, went to Perrigo Co. for $8.6 billion, with the tax rate cited as one of the driving forces of the deal. (BioWorld Today, July 30, 2013.)

Jazz Pharmaceuticals plc shifted its headquarters to Ireland in 2011 through the purchase of Azur Pharma Ltd. Since then, the firm has engaged in a spree of business development activities, most recently acquiring Eusa Pharma Ltd. and Gentium SpA and licensing rights to a narcolepsy drug from Aerial Biopharma LLC. (See BioWorld Today, April 30, 2013, Dec. 23, 2013, and Jan. 14, 2014.)

In October, Parsippany, N.J.-based Actavis Inc. bought Dublin-based Warner Chilcott plc in a stock-for-stock deal worth about $8.5 billion, with analysts pointing to the lower tax rate as one of the primary advantages to Actavis. (See BioWorld Today, May 23, 2013.)

Benefits to Horizon are expected, too. Walbert explained that, prior to the Vidara deal, Horizon’s future tax rate percentage was expected to fall in the high 30s. As an Irish corporation, the company’s future expected tax rate will be in the low 20 percent range, possibly even lower.

But he assured investors that the lower tax rate was not the sole reason for the acquisition. “We have always been focused on targeted assets,” he said. In addition to its primary care offerings, Horizon also markets Rayos, a delayed-release form of low-dose prednisone, known as Lodotra in Europe, that is directed to the rheumatology market.

“We think Actimmune will fit nicely” in the portfolio, he added, and it “leverages our past experience in the biologics and orphan disease [space].”

‘AGGRESSIVE’ BD STRATEGY TO CONTINUE

Horizon’s marketing power also could unlock the full sales potential for Actimmune, which has had only modest promotion with Vidara’s small sales team.

Designed to act as a biologic response modifier, Actimmune is indicated for reducing the frequency and severity of serious infections – usually bacterial or fungal in nature – associated with CGD, a disease with an estimated prevalence of one in 200,000 births.

It’s also approved for delaying time to disease progression in patients with SMO, a congenital disorder of bone resorption by osteoclasts that causes impaired bone remodeling. SMO comprises an even smaller patient population, about one in 200,000 to 500,000 births.

Cowen and Co. analyst Edward Nash said in a research note that there are about 1,900 patients in the U.S. with CGD or SMO who are eligible for Actimmune therapy and that IMS Health reported total prescriptions of 3,110 in 2013. Though that marks a 67.3 percent increase over 2012, “the market penetration remains quite low,” Nash wrote.

Horizon, meanwhile, has a “well-established sales force of 290 reps and has successfully implemented the business model of targeted promotion to both specialists and [primary care physicians]. Therefore, we believe Horizon will be able to leverage Actimmune into achieving its full potential.”

Nash noted in a research report last week that the company already had success with recently acquired Vimovo, reversing the downward prescribing trend attributed to the lack of active promotion by previous licensee Astrazeneca plc. Following Horizon’s acquisition of the gastro-friendly NSAID, prescription numbers have been rising, and Cowen expects “the upward trend to continue or even accelerate.”

Further merger and licensing deals could bring more products into the Horizon pipeline. “We see many opportunities with drugs either neglected by large pharma or that have failed to thrive in the wrong hands,” Nash said.

During the investor call, Horizon’s Walbert acknowledged that the company plans to seek out additional opportunities. Though he offered no specific details, the firm will be “aggressive” in its business development activities, he added.