UPDATE 2-ViroPharma to buy Lev Pharma for $442.9 mln

(Adds details from conference call, analysts and company's comment, updates share movement)

By Jennifer Robin Raj

BANGALORE, July 15 (Reuters) - ViroPharma Inc (VPHM.O: Quote, Profile, Research) said it agreed to acquire Lev Pharmaceuticals Inc LEVP.OB for $442.9 million in cash and stock, to add Lev's Cinryze, which targets hereditary angioedema disease (HAE), to its pipeline.

However, ViroPharma shares took a hit as investors questioned the market potential of Cinryze, which faces competition for approval from several other drug candidates.

ViroPharma shares fell as much as 23 percent on news of the deal, which pays Lev shareholders $2.75 a share, or a 49 percent premium to Lev's Monday close.

"It's very hard to understand why ViroPharma would pay such a significant premium to gain access to what could end up being a very small drug," Susquehanna Financical Group analyst Jason Kolbert said and called the deal "very disappointing".

In a conference call, ViroPharma's Chief Executive Vincent Milano said, "We believe Cinryze to be atleast $250 million to $350 million product a year at peak, with margins of between 65 percent and 70 percent."

However, Kolbert said investors were not wholly convinced of the estimate.

ViroPharma's spokeswoman Kristina Broadbelt said the company's projections were based on sales of other orphan drugs that treat very rare diseases.