* Plans to submit U.S. marketing app by late 2017/early 2018
* Potential peak sales of more than $2 bln - analysts
* Data protects and grows Shire’s HAE franchise - analysts
* U.S. shares rise 3.4 pct, UK stock up 1.7 pct (Adds conference call details, analyst comment; updates shares)
By Natalie Grover
May 18 (Reuters) - Successful late-stage data on Shire Plc’s , long-acting preventative treatment for hereditary angioedema (HAE) brings the Dublin-based drugmaker one step closer to U.S. approval, it said on Thursday.
U.S.-listed shares of the rare disease drugmaker, which already sells several HAE treatments, were up about 3.4 percent at $188.23 in late-morning trading.
The drug, lanadelumab, which is expected to generate more than $2 billion in peak sales will help Shire protect and grow its existing HAE franchise, which accounts for about 10 percent of its profit, analysts said.
Patients with HAE suffer from recurrent episodes of severe swelling, typically in the extremities, gastrointestinal tract and upper airways. It affects about one in 50,000 people, according to the U.S. National Institutes of Health.
Existing treatments in the United States are either injections for acute attacks or short-acting intravenous infusions administered twice a week.
In Shire’s late-stage study, three dosing arms of lanadelumab (150 or 300 mg every four weeks or 300 mg every two weeks) were tested against a placebo in 125 patients.
Treatment with the drug induced a statistically significant reduction in attacks across all regimens, regardless of baseline attack rate, Shire said.
In particular, the 300 mg dose reduced the monthly attack rate by 87 percent versus a placebo when given every two weeks.
Data also showed that a significantly higher proportion of patients on lanadelumab were attack free for the 26-week study.
Given lanadelumab’s compelling efficacy and advantage over existing treatments, Deutsche Bank analysts said they expected it to dominate and significantly expand the current $1.8 billion HAE prophylaxis market.
The U.S. Food and Drug Administration has already granted the drug - which Shire acquired through its $5.9 billion buyout of Dyax in 2016 - “orphan drug” and “breakthrough therapy” designations.
Shire said it planned to submit a U.S. marketing application for lanadelumab by late 2017/early 2018. The company also expects to submit an EU application in the first half of next year, pending regulatory discussions.
On a conference call with analysts, Shire said it was still analyzing the dataset and did not provide any clarity on pricing.
Shire’s existing HAE drugs include Kalbitor, Cinryze and Firazyr. Other FDA-approved treatments include CSL Behring’s Berinert and Valeant Pharmaceuticals International Inc’s , Ruconest.
Shire’s UK-listed shares were up 1.7 percent at 4814.5 pence.
Shares of U.S. drugmaker BioCryst Pharmaceuticals Inc , which is developing an oral HAE drug, were up about 6 percent.
Reporting by Natalie Grover in Bengaluru; Editing by Saumyadeb Chakrabarty and Martina D'Couto