Pharma BD Deal Intelligence
Pfizer paid ~$195M for Encysive to gain Thelin, a pulmonary arterial hypertension drug the FDA had already rejected three times on approvable letters. Pfizer never won U.S. approval either, and voluntarily withdrew Thelin worldwide in December 2010 after fatal liver injury cases—a near-total loss.
Pfizer paid ~$195M for a PAH drug the FDA had already rejected twice, then watched it get pulled worldwide in 2010 over fatal liver toxicity — a near-total loss.
Full analysis, sources & comparables →The $2.35-per-share buyout — a 117% premium — saves the struggling biotech from NASDAQ delisting after Thelin received three approvable letters from FDA, the…
Pfizer announced cash tender offer at $2.35/share (~$195M equity value) to acquire Encysive, citing near-term EU revenue from Thelin and complementarity with…
Pfizer voluntarily withdrew sitaxentan worldwide on December 10, 2010 citing fatal liver damage; the drug had failed three FDA approvable cycles and never…
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Pfizer acquired Encysive Pharmaceuticals via a cash tender offer at $2.35 per share (approximately $195 million equity value, a roughly 117-118% premium), gaining Thelin (sitaxentan), an oral pulmonary arterial hypertension drug already approved in the EU, Australia and Canada but still pending U.S. FDA approval after three approvable letters. Pfizer planned a required Phase III trial to pursue U.S. approval alongside its existing Revatio PAH franchise; Pfizer voluntarily withdrew sitaxentan worldwide in December 2010 after reports of fatal liver damage.
Pfizer paid ~$195M for a PAH drug the FDA had already rejected twice, then watched it get pulled worldwide in 2010 over fatal liver toxicity — a near-total loss.
Assessment window: 15yr post-close.
Pulmonary arterial hypertension (PAH) is a progressive, life-threatening condition characterized by elevated pressure in the pulmonary arteries, causing right-heart strain, exercise intolerance, and ultimately right-heart failure. It disproportionately affects women aged 20-40 and historically had a poor prognosis without targeted vasodilator therapy.
In 2008 the PAH market was anchored by three drug classes: endothelin receptor antagonists (Actelion's Tracleer/bosentan, the dominant ERA franchise), PDE5 inhibitors (Pfizer's Revatio/sildenafil and Eli Lilly's Adcirca/tadalafil), and prostacyclin analogs (United Therapeutics' Remodulin/treprostinil and GSK's Flolan/epoprostenol). Encysive's Thelin (sitaxsentan sodium) was a selective endothelin-A receptor antagonist marketed in the EU, Canada, and Australia (approvals 2006-2007) but had received three FDA approvable letters with unresolved STRIDE-2 efficacy concerns and never gained US approval. For Pfizer, the $195M cash tender ($2.35/share — a 118% premium accepted unanimously by Encysive's board) added near-term EU revenue and complemented its existing Revatio PAH franchise. The strategic case unraveled rapidly: Pfizer voluntarily withdrew Thelin worldwide in December 2010 after fatal hepatotoxicity reports, ending the asset's commercial life roughly two years post-acquisition.
| Deal | Year | Value | Outcome |
|---|---|---|---|
| Pfizer Inc. / Encysive Pharmaceuticals Inc. (this deal) | 2008 | $195M | 9 |
| Pfizer Inc. / BioNTech SE | 2020 | $748M | 100 |
| Pfizer Inc. / FoldRx Pharmaceuticals | 2010 | — | 99 |
| Pfizer Inc. / Medivation Inc. | 2016 | $14.0B | 86 |
| Pfizer Inc. / Wyeth | 2009 | $68.0B | 86 |
| Pfizer Inc. / Warner-Lambert Company | 2000 | $90.0B | 83 |
| Pfizer Inc. / Arvinas, Inc. | 2021 | $2.4B | 77 |
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