Shire strengthens position in rare diseases with $4.2 billion buy of ViroPharma

Ireland-based drugmaker Shire (LSE: SHP) saw its share rise 2.2% to £33.16 shortly after markets opened this morning, after it said it has agreed terms to acquire US orphan drug company ViroPharma (Nasdaq: VPHM) for $50 a share in cash.

Under the accord, which has been approved by both companies’ boards of directors, Shire will acquire all the outstanding shares of the rare disease company ViroPharma for $$4.2 billion. The $50 per share price in the transaction represents a 27% premium to ViroPharma's closing share price on Friday, November 8, the last trading day prior to announcement, and a 64% premium to ViroPharma's unaffected share price of $30.47 on September 12, 2013. The transaction could close before year-end or first quarter 2014.

ViroPharma is a high growth, rare disease biopharmaceutical company, whose commercial product Cinryze (C1 esterase inhibitor [human]), is a leading brand for the prophylactic treatment of hereditary angioedema (HAE). Back in September, not only Shire but also French drug major Sanofi (Euronext: SAN) were said to be interested in buying ViroPharma.